Re: [HACKERS] WAL logging problem in 9.4.3? - Mailing list pgsql-hackers
| From | Kyotaro Horiguchi |
|---|---|
| Subject | Re: [HACKERS] WAL logging problem in 9.4.3? |
| Date | |
| Msg-id | 20191128.205620.2015649987051831334.horikyota.ntt@gmail.com Whole thread Raw |
| In response to | Re: [HACKERS] WAL logging problem in 9.4.3? (Kyotaro Horiguchi <horikyota.ntt@gmail.com>) |
| Responses |
Re: [HACKERS] WAL logging problem in 9.4.3?
(Kyotaro Horiguchi <horikyota.ntt@gmail.com>)
|
| List | pgsql-hackers |
At Tue, 26 Nov 2019 21:37:52 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail> Is is not fully checked. I didn't
mergedand mesured performance yet,
> but I post the status-quo patch for now.
It was actually inconsistency caused by swap_relation_files.
1. rd_createSubid of relcache for r2 is not turned off. This prevents
the relcache entry from flushed. Commit processes pendingSyncs and
leaves the relcache entry with rd_createSubid != Invalid. It is
inconsistency.
2. relation_open(r1) returns a relcache entry with its relfilenode has
the old value (relfilenode1) since command counter has not been
incremented. On the other hand if it is incremented just before,
AssertPendingSyncConsistency() aborts because of the inconsistency
between relfilenode and rd_firstRel*.
As the result, I returned to think that we need to modify both
relcache entries with right relfilenode.
I once thought that taking AEL in the function has no side effect but
the code path is executed also when wal_level = replica or higher. And
as I mentioned upthread, we can even get there without taking any lock
on r1 or sometimes ShareLock. So upgrading to AEL emits Standby/LOCK
WAL and propagates to standby. After all I'd like to take the weakest
lock (AccessShareLock) there.
The attached is the new version of the patch.
- v26-0001-version-nm24.patch
Same with v24
- v26-0002-change-swap_relation_files.patch
Changes to swap_relation_files as mentioned above.
- v26-0003-Improve-the-performance-of-relation-syncs.patch
Do multiple pending syncs by one shared_buffers scanning.
- v26-0004-Revert-FlushRelationBuffersWithoutRelcache.patch
v26-0003 makes the function useless. Remove it.
- v26-0005-Fix-gistGetFakeLSN.patch
gistGetFakeLSN fix.
- v26-0006-Sync-files-shrinked-by-truncation.patch
Fix the problem of commit-time-FPI after truncation after checkpoint.
I'm not sure this is the right direction but pendingSyncHash is
removed from pendingDeletes list again.
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center
From ee96bb1e14969823eab79ab1531d68e8aadc1915 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 21 Nov 2019 15:28:06 +0900
Subject: [PATCH v26 1/6] version nm24
Noah Misch's version 24.
---
doc/src/sgml/config.sgml | 43 +++--
doc/src/sgml/perform.sgml | 47 ++----
src/backend/access/gist/gistutil.c | 7 +-
src/backend/access/heap/heapam.c | 45 +-----
src/backend/access/heap/heapam_handler.c | 22 +--
src/backend/access/heap/rewriteheap.c | 21 +--
src/backend/access/nbtree/nbtsort.c | 41 ++---
src/backend/access/transam/README | 47 +++++-
src/backend/access/transam/xact.c | 14 ++
src/backend/access/transam/xloginsert.c | 10 +-
src/backend/access/transam/xlogutils.c | 17 +-
src/backend/catalog/heap.c | 4 +
src/backend/catalog/storage.c | 198 +++++++++++++++++++++--
src/backend/commands/cluster.c | 11 ++
src/backend/commands/copy.c | 58 +------
src/backend/commands/createas.c | 11 +-
src/backend/commands/matview.c | 12 +-
src/backend/commands/tablecmds.c | 11 +-
src/backend/storage/buffer/bufmgr.c | 37 +++--
src/backend/storage/smgr/md.c | 9 +-
src/backend/utils/cache/relcache.c | 122 ++++++++++----
src/backend/utils/misc/guc.c | 13 ++
src/include/access/heapam.h | 3 -
src/include/access/rewriteheap.h | 2 +-
src/include/access/tableam.h | 18 +--
src/include/catalog/storage.h | 5 +
src/include/storage/bufmgr.h | 5 +
src/include/utils/rel.h | 57 +++++--
src/include/utils/relcache.h | 8 +-
src/test/regress/pg_regress.c | 2 +
30 files changed, 551 insertions(+), 349 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d4d1fe45cc..d0f7dbd7d7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2483,21 +2483,14 @@ include_dir 'conf.d'
levels. This parameter can only be set at server start.
</para>
<para>
- In <literal>minimal</literal> level, WAL-logging of some bulk
- operations can be safely skipped, which can make those
- operations much faster (see <xref linkend="populate-pitr"/>).
- Operations in which this optimization can be applied include:
- <simplelist>
- <member><command>CREATE TABLE AS</command></member>
- <member><command>CREATE INDEX</command></member>
- <member><command>CLUSTER</command></member>
- <member><command>COPY</command> into tables that were created or truncated in the same
- transaction</member>
- </simplelist>
- But minimal WAL does not contain enough information to reconstruct the
- data from a base backup and the WAL logs, so <literal>replica</literal> or
- higher must be used to enable WAL archiving
- (<xref linkend="guc-archive-mode"/>) and streaming replication.
+ In <literal>minimal</literal> level, no information is logged for
+ tables or indexes for the remainder of a transaction that creates or
+ truncates them. This can make bulk operations much faster (see
+ <xref linkend="populate-pitr"/>). But minimal WAL does not contain
+ enough information to reconstruct the data from a base backup and the
+ WAL logs, so <literal>replica</literal> or higher must be used to
+ enable WAL archiving (<xref linkend="guc-archive-mode"/>) and
+ streaming replication.
</para>
<para>
In <literal>logical</literal> level, the same information is logged as
@@ -2889,6 +2882,26 @@ include_dir 'conf.d'
</listitem>
</varlistentry>
+ <varlistentry id="guc-wal-skip-threshold" xreflabel="wal_skip_threshold">
+ <term><varname>wal_skip_threshold</varname> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>wal_skip_threshold</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ When <varname>wal_level</varname> is <literal>minimal</literal> and a
+ transaction commits after creating or rewriting a permanent table,
+ materialized view, or index, this setting determines how to persist
+ the new data. If the data is smaller than this setting, write it to
+ the WAL log; otherwise, use an fsync of the data file. Depending on
+ the properties of your storage, raising or lowering this value might
+ help if such commits are slowing concurrent transactions. The default
+ is 64 kilobytes (<literal>64kB</literal>).
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-commit-delay" xreflabel="commit_delay">
<term><varname>commit_delay</varname> (<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml
index 715aff63c8..fcc60173fb 100644
--- a/doc/src/sgml/perform.sgml
+++ b/doc/src/sgml/perform.sgml
@@ -1605,8 +1605,8 @@ SELECT * FROM x, y, a, b, c WHERE something AND somethingelse;
needs to be written, because in case of an error, the files
containing the newly loaded data will be removed anyway.
However, this consideration only applies when
- <xref linkend="guc-wal-level"/> is <literal>minimal</literal> for
- non-partitioned tables as all commands must write WAL otherwise.
+ <xref linkend="guc-wal-level"/> is <literal>minimal</literal>
+ as all commands must write WAL otherwise.
</para>
</sect2>
@@ -1706,42 +1706,13 @@ SELECT * FROM x, y, a, b, c WHERE something AND somethingelse;
</para>
<para>
- Aside from avoiding the time for the archiver or WAL sender to
- process the WAL data,
- doing this will actually make certain commands faster, because they
- are designed not to write WAL at all if <varname>wal_level</varname>
- is <literal>minimal</literal>. (They can guarantee crash safety more cheaply
- by doing an <function>fsync</function> at the end than by writing WAL.)
- This applies to the following commands:
- <itemizedlist>
- <listitem>
- <para>
- <command>CREATE TABLE AS SELECT</command>
- </para>
- </listitem>
- <listitem>
- <para>
- <command>CREATE INDEX</command> (and variants such as
- <command>ALTER TABLE ADD PRIMARY KEY</command>)
- </para>
- </listitem>
- <listitem>
- <para>
- <command>ALTER TABLE SET TABLESPACE</command>
- </para>
- </listitem>
- <listitem>
- <para>
- <command>CLUSTER</command>
- </para>
- </listitem>
- <listitem>
- <para>
- <command>COPY FROM</command>, when the target table has been
- created or truncated earlier in the same transaction
- </para>
- </listitem>
- </itemizedlist>
+ Aside from avoiding the time for the archiver or WAL sender to process the
+ WAL data, doing this will actually make certain commands faster, because
+ they do not to write WAL at all if <varname>wal_level</varname>
+ is <literal>minimal</literal> and the current subtransaction (or top-level
+ transaction) created or truncated the table or index they change. (They
+ can guarantee crash safety more cheaply by doing
+ an <function>fsync</function> at the end than by writing WAL.)
</para>
</sect2>
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 553a6d67b1..66c52d6dd6 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,12 @@ gistGetFakeLSN(Relation rel)
{
static XLogRecPtr counter = FirstNormalUnloggedLSN;
- if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+ /*
+ * XXX before commit fix this. This is not correct for
+ * RELPERSISTENCE_PERMANENT, but it suffices to make tests pass.
+ */
+ if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP
+ || rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT)
{
/*
* Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 0128bb34ef..be19c34cbd 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -21,7 +21,6 @@
* heap_multi_insert - insert multiple tuples into a relation
* heap_delete - delete a tuple from a relation
* heap_update - replace a tuple in a relation with another tuple
- * heap_sync - sync heap, for when no WAL has been written
*
* NOTES
* This file contains the heap_ routines which implement
@@ -1936,7 +1935,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
MarkBufferDirty(buffer);
/* XLOG stuff */
- if (!(options & HEAP_INSERT_SKIP_WAL) && RelationNeedsWAL(relation))
+ if (RelationNeedsWAL(relation))
{
xl_heap_insert xlrec;
xl_heap_header xlhdr;
@@ -2119,7 +2118,7 @@ heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
/* currently not needed (thus unsupported) for heap_multi_insert() */
AssertArg(!(options & HEAP_INSERT_NO_LOGICAL));
- needwal = !(options & HEAP_INSERT_SKIP_WAL) && RelationNeedsWAL(relation);
+ needwal = RelationNeedsWAL(relation);
saveFreeSpace = RelationGetTargetPageFreeSpace(relation,
HEAP_DEFAULT_FILLFACTOR);
@@ -8920,46 +8919,6 @@ heap2_redo(XLogReaderState *record)
}
}
-/*
- * heap_sync - sync a heap, for use when no WAL has been written
- *
- * This forces the heap contents (including TOAST heap if any) down to disk.
- * If we skipped using WAL, and WAL is otherwise needed, we must force the
- * relation down to disk before it's safe to commit the transaction. This
- * requires writing out any dirty buffers and then doing a forced fsync.
- *
- * Indexes are not touched. (Currently, index operations associated with
- * the commands that use this are WAL-logged and so do not need fsync.
- * That behavior might change someday, but in any case it's likely that
- * any fsync decisions required would be per-index and hence not appropriate
- * to be done here.)
- */
-void
-heap_sync(Relation rel)
-{
- /* non-WAL-logged tables never need fsync */
- if (!RelationNeedsWAL(rel))
- return;
-
- /* main heap */
- FlushRelationBuffers(rel);
- /* FlushRelationBuffers will have opened rd_smgr */
- smgrimmedsync(rel->rd_smgr, MAIN_FORKNUM);
-
- /* FSM is not critical, don't bother syncing it */
-
- /* toast heap, if any */
- if (OidIsValid(rel->rd_rel->reltoastrelid))
- {
- Relation toastrel;
-
- toastrel = table_open(rel->rd_rel->reltoastrelid, AccessShareLock);
- FlushRelationBuffers(toastrel);
- smgrimmedsync(toastrel->rd_smgr, MAIN_FORKNUM);
- table_close(toastrel, AccessShareLock);
- }
-}
-
/*
* Mask a heap page before performing consistency checks on it.
*/
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 92073fec54..07fe717faa 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -555,17 +555,6 @@ tuple_lock_retry:
return result;
}
-static void
-heapam_finish_bulk_insert(Relation relation, int options)
-{
- /*
- * If we skipped writing WAL, then we need to sync the heap (but not
- * indexes since those use WAL anyway / don't go through tableam)
- */
- if (options & HEAP_INSERT_SKIP_WAL)
- heap_sync(relation);
-}
-
/* ------------------------------------------------------------------------
* DDL related callbacks for heap AM.
@@ -698,7 +687,6 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
IndexScanDesc indexScan;
TableScanDesc tableScan;
HeapScanDesc heapScan;
- bool use_wal;
bool is_system_catalog;
Tuplesortstate *tuplesort;
TupleDesc oldTupDesc = RelationGetDescr(OldHeap);
@@ -713,12 +701,9 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
is_system_catalog = IsSystemRelation(OldHeap);
/*
- * We need to log the copied data in WAL iff WAL archiving/streaming is
- * enabled AND it's a WAL-logged rel.
+ * Valid smgr_targblock implies something already wrote to the relation.
+ * This may be harmless, but this function hasn't planned for it.
*/
- use_wal = XLogIsNeeded() && RelationNeedsWAL(NewHeap);
-
- /* use_wal off requires smgr_targblock be initially invalid */
Assert(RelationGetTargetBlock(NewHeap) == InvalidBlockNumber);
/* Preallocate values/isnull arrays */
@@ -728,7 +713,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap,
/* Initialize the rewrite operation */
rwstate = begin_heap_rewrite(OldHeap, NewHeap, OldestXmin, *xid_cutoff,
- *multi_cutoff, use_wal);
+ *multi_cutoff);
/* Set up sorting if wanted */
@@ -2515,7 +2500,6 @@ static const TableAmRoutine heapam_methods = {
.tuple_delete = heapam_tuple_delete,
.tuple_update = heapam_tuple_update,
.tuple_lock = heapam_tuple_lock,
- .finish_bulk_insert = heapam_finish_bulk_insert,
.tuple_fetch_row_version = heapam_fetch_row_version,
.tuple_get_latest_tid = heap_get_latest_tid,
diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
index d285b1f390..3e564838fa 100644
--- a/src/backend/access/heap/rewriteheap.c
+++ b/src/backend/access/heap/rewriteheap.c
@@ -136,7 +136,6 @@ typedef struct RewriteStateData
Page rs_buffer; /* page currently being built */
BlockNumber rs_blockno; /* block where page will go */
bool rs_buffer_valid; /* T if any tuples in buffer */
- bool rs_use_wal; /* must we WAL-log inserts? */
bool rs_logical_rewrite; /* do we need to do logical rewriting */
TransactionId rs_oldest_xmin; /* oldest xmin used by caller to determine
* tuple visibility */
@@ -230,15 +229,13 @@ static void logical_end_heap_rewrite(RewriteState state);
* oldest_xmin xid used by the caller to determine which tuples are dead
* freeze_xid xid before which tuples will be frozen
* cutoff_multi multixact before which multis will be removed
- * use_wal should the inserts to the new heap be WAL-logged?
*
* Returns an opaque RewriteState, allocated in current memory context,
* to be used in subsequent calls to the other functions.
*/
RewriteState
begin_heap_rewrite(Relation old_heap, Relation new_heap, TransactionId oldest_xmin,
- TransactionId freeze_xid, MultiXactId cutoff_multi,
- bool use_wal)
+ TransactionId freeze_xid, MultiXactId cutoff_multi)
{
RewriteState state;
MemoryContext rw_cxt;
@@ -263,7 +260,6 @@ begin_heap_rewrite(Relation old_heap, Relation new_heap, TransactionId oldest_xm
/* new_heap needn't be empty, just locked */
state->rs_blockno = RelationGetNumberOfBlocks(new_heap);
state->rs_buffer_valid = false;
- state->rs_use_wal = use_wal;
state->rs_oldest_xmin = oldest_xmin;
state->rs_freeze_xid = freeze_xid;
state->rs_cutoff_multi = cutoff_multi;
@@ -322,7 +318,7 @@ end_heap_rewrite(RewriteState state)
/* Write the last page, if any */
if (state->rs_buffer_valid)
{
- if (state->rs_use_wal)
+ if (RelationNeedsWAL(state->rs_new_rel))
log_newpage(&state->rs_new_rel->rd_node,
MAIN_FORKNUM,
state->rs_blockno,
@@ -337,18 +333,14 @@ end_heap_rewrite(RewriteState state)
}
/*
- * If the rel is WAL-logged, must fsync before commit. We use heap_sync
- * to ensure that the toast table gets fsync'd too.
- *
- * It's obvious that we must do this when not WAL-logging. It's less
- * obvious that we have to do it even if we did WAL-log the pages. The
+ * When we WAL-logged rel pages, we must nonetheless fsync them. The
* reason is the same as in storage.c's RelationCopyStorage(): we're
* writing data that's not in shared buffers, and so a CHECKPOINT
* occurring during the rewriteheap operation won't have fsync'd data we
* wrote before the checkpoint.
*/
if (RelationNeedsWAL(state->rs_new_rel))
- heap_sync(state->rs_new_rel);
+ smgrimmedsync(state->rs_new_rel->rd_smgr, MAIN_FORKNUM);
logical_end_heap_rewrite(state);
@@ -646,9 +638,6 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
{
int options = HEAP_INSERT_SKIP_FSM;
- if (!state->rs_use_wal)
- options |= HEAP_INSERT_SKIP_WAL;
-
/*
* While rewriting the heap for VACUUM FULL / CLUSTER, make sure data
* for the TOAST table are not logically decoded. The main heap is
@@ -687,7 +676,7 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
/* Doesn't fit, so write out the existing page */
/* XLOG stuff */
- if (state->rs_use_wal)
+ if (RelationNeedsWAL(state->rs_new_rel))
log_newpage(&state->rs_new_rel->rd_node,
MAIN_FORKNUM,
state->rs_blockno,
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index 1dd39a9535..b61692aefc 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -31,18 +31,6 @@
* them. They will need to be re-read into shared buffers on first use after
* the build finishes.
*
- * Since the index will never be used unless it is completely built,
- * from a crash-recovery point of view there is no need to WAL-log the
- * steps of the build. After completing the index build, we can just sync
- * the whole file to disk using smgrimmedsync() before exiting this module.
- * This can be seen to be sufficient for crash recovery by considering that
- * it's effectively equivalent to what would happen if a CHECKPOINT occurred
- * just after the index build. However, it is clearly not sufficient if the
- * DBA is using the WAL log for PITR or replication purposes, since another
- * machine would not be able to reconstruct the index from WAL. Therefore,
- * we log the completed index pages to WAL if and only if WAL archiving is
- * active.
- *
* This code isn't concerned about the FSM at all. The caller is responsible
* for initializing that.
*
@@ -563,12 +551,7 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
wstate.heap = btspool->heap;
wstate.index = btspool->index;
wstate.inskey = _bt_mkscankey(wstate.index, NULL);
-
- /*
- * We need to log index creation in WAL iff WAL archiving/streaming is
- * enabled UNLESS the index isn't WAL-logged anyway.
- */
- wstate.btws_use_wal = XLogIsNeeded() && RelationNeedsWAL(wstate.index);
+ wstate.btws_use_wal = RelationNeedsWAL(wstate.index);
/* reserve the metapage */
wstate.btws_pages_alloced = BTREE_METAPAGE + 1;
@@ -1265,21 +1248,15 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
_bt_uppershutdown(wstate, state);
/*
- * If the index is WAL-logged, we must fsync it down to disk before it's
- * safe to commit the transaction. (For a non-WAL-logged index we don't
- * care since the index will be uninteresting after a crash anyway.)
- *
- * It's obvious that we must do this when not WAL-logging the build. It's
- * less obvious that we have to do it even if we did WAL-log the index
- * pages. The reason is that since we're building outside shared buffers,
- * a CHECKPOINT occurring during the build has no way to flush the
- * previously written data to disk (indeed it won't know the index even
- * exists). A crash later on would replay WAL from the checkpoint,
- * therefore it wouldn't replay our earlier WAL entries. If we do not
- * fsync those pages here, they might still not be on disk when the crash
- * occurs.
+ * When we WAL-logged index pages, we must nonetheless fsync index files.
+ * Since we're building outside shared buffers, a CHECKPOINT occurring
+ * during the build has no way to flush the previously written data to
+ * disk (indeed it won't know the index even exists). A crash later on
+ * would replay WAL from the checkpoint, therefore it wouldn't replay our
+ * earlier WAL entries. If we do not fsync those pages here, they might
+ * still not be on disk when the crash occurs.
*/
- if (RelationNeedsWAL(wstate->index))
+ if (wstate->btws_use_wal)
{
RelationOpenSmgr(wstate->index);
smgrimmedsync(wstate->index->rd_smgr, MAIN_FORKNUM);
diff --git a/src/backend/access/transam/README b/src/backend/access/transam/README
index b5a2cb2de8..641809cfda 100644
--- a/src/backend/access/transam/README
+++ b/src/backend/access/transam/README
@@ -717,6 +717,40 @@ then restart recovery. This is part of the reason for not writing a WAL
entry until we've successfully done the original action.
+Skipping WAL for New RelFileNode
+--------------------------------
+
+Under wal_level=minimal, if a change modifies a relfilenode that
+RollbackAndReleaseCurrentSubTransaction() would unlink, in-tree access methods
+write no WAL for that change. For any access method, CommitTransaction()
+writes and fsyncs affected blocks before recording the commit. This skipping
+is mandatory; if a WAL-writing change preceded a WAL-skipping change for the
+same block, REDO could overwrite the WAL-skipping change. Code that writes
+WAL without calling RelationNeedsWAL() must check for this case.
+
+If skipping were not mandatory, a related problem would arise. Suppose, under
+full_page_writes=off, a WAL-writing change follows a WAL-skipping change.
+When a WAL record contains no full-page image, REDO expects the page to match
+its contents from just before record insertion. A WAL-skipping change may not
+reach disk at all, violating REDO's expectation.
+
+Prefer to do the same in future access methods. However, two other approaches
+can work. First, an access method can irreversibly transition a given fork
+from WAL-skipping to WAL-writing by calling FlushRelationBuffers() and
+smgrimmedsync(). Second, an access method can opt to write WAL
+unconditionally for permanent relations. When using the second method, do not
+call RelationCopyStorage(), which skips WAL.
+
+This applies only to WAL records whose replay would modify bytes stored in the
+new relfilenode. It does not apply to other records about the relfilenode,
+such as XLOG_SMGR_CREATE. Because it operates at the level of individual
+relfilenodes, RelationNeedsWAL() can differ for tightly-coupled relations.
+Consider "CREATE TABLE t (); BEGIN; ALTER TABLE t ADD c text; ..." in which
+ALTER TABLE adds a TOAST relation. The TOAST relation will skip WAL, while
+the table owning it will not. ALTER TABLE SET TABLESPACE will cause a table
+to skip WAL, but that won't affect its indexes.
+
+
Asynchronous Commit
-------------------
@@ -820,13 +854,12 @@ Changes to a temp table are not WAL-logged, hence could reach disk in
advance of T1's commit, but we don't care since temp table contents don't
survive crashes anyway.
-Database writes made via any of the paths we have introduced to avoid WAL
-overhead for bulk updates are also safe. In these cases it's entirely
-possible for the data to reach disk before T1's commit, because T1 will
-fsync it down to disk without any sort of interlock, as soon as it finishes
-the bulk update. However, all these paths are designed to write data that
-no other transaction can see until after T1 commits. The situation is thus
-not different from ordinary WAL-logged updates.
+Database writes that skip WAL for new relfilenodes are also safe. In these
+cases it's entirely possible for the data to reach disk before T1's commit,
+because T1 will fsync it down to disk without any sort of interlock. However,
+all these paths are designed to write data that no other transaction can see
+until after T1 commits. The situation is thus not different from ordinary
+WAL-logged updates.
Transaction Emulation during Recovery
-------------------------------------
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 5c0d0f2af0..750f95c482 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2109,6 +2109,13 @@ CommitTransaction(void)
*/
PreCommit_on_commit_actions();
+ /*
+ * Synchronize files that are created and not WAL-logged during this
+ * transaction. This must happen before AtEOXact_RelationMap(), so that we
+ * don't see committed-but-broken files after a crash.
+ */
+ smgrDoPendingSyncs();
+
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
@@ -2342,6 +2349,13 @@ PrepareTransaction(void)
*/
PreCommit_on_commit_actions();
+ /*
+ * Synchronize files that are created and not WAL-logged during this
+ * transaction. This must happen before EndPrepare(), so that we don't see
+ * committed-but-broken files after a crash and COMMIT PREPARED.
+ */
+ smgrDoPendingSyncs();
+
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c
index aa9dca0036..dda1dea08b 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -1043,8 +1043,13 @@ log_newpage_range(Relation rel, ForkNumber forkNum,
BlockNumber startblk, BlockNumber endblk,
bool page_std)
{
+ int flags;
BlockNumber blkno;
+ flags = REGBUF_FORCE_IMAGE;
+ if (page_std)
+ flags |= REGBUF_STANDARD;
+
/*
* Iterate over all the pages in the range. They are collected into
* batches of XLR_MAX_BLOCK_ID pages, and a single WAL-record is written
@@ -1066,7 +1071,8 @@ log_newpage_range(Relation rel, ForkNumber forkNum,
nbufs = 0;
while (nbufs < XLR_MAX_BLOCK_ID && blkno < endblk)
{
- Buffer buf = ReadBuffer(rel, blkno);
+ Buffer buf = ReadBufferExtended(rel, forkNum, blkno,
+ RBM_NORMAL, NULL);
LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
@@ -1088,7 +1094,7 @@ log_newpage_range(Relation rel, ForkNumber forkNum,
START_CRIT_SECTION();
for (i = 0; i < nbufs; i++)
{
- XLogRegisterBuffer(i, bufpack[i], REGBUF_FORCE_IMAGE | REGBUF_STANDARD);
+ XLogRegisterBuffer(i, bufpack[i], flags);
MarkBufferDirty(bufpack[i]);
}
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 446760ed6e..9561e30b08 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -544,6 +544,8 @@ typedef FakeRelCacheEntryData *FakeRelCacheEntry;
* fields related to physical storage, like rd_rel, are initialized, so the
* fake entry is only usable in low-level operations like ReadBuffer().
*
+ * This is also used for syncing WAL-skipped files.
+ *
* Caller must free the returned entry with FreeFakeRelcacheEntry().
*/
Relation
@@ -552,18 +554,19 @@ CreateFakeRelcacheEntry(RelFileNode rnode)
FakeRelCacheEntry fakeentry;
Relation rel;
- Assert(InRecovery);
-
/* Allocate the Relation struct and all related space in one block. */
fakeentry = palloc0(sizeof(FakeRelCacheEntryData));
rel = (Relation) fakeentry;
rel->rd_rel = &fakeentry->pgc;
rel->rd_node = rnode;
- /* We will never be working with temp rels during recovery */
+ /*
+ * We will never be working with temp rels during recovery or while
+ * syncing WAL-skipped files.
+ */
rel->rd_backend = InvalidBackendId;
- /* It must be a permanent table if we're in recovery. */
+ /* It must be a permanent table here */
rel->rd_rel->relpersistence = RELPERSISTENCE_PERMANENT;
/* We don't know the name of the relation; use relfilenode instead */
@@ -572,9 +575,9 @@ CreateFakeRelcacheEntry(RelFileNode rnode)
/*
* We set up the lockRelId in case anything tries to lock the dummy
* relation. Note that this is fairly bogus since relNode may be
- * different from the relation's OID. It shouldn't really matter though,
- * since we are presumably running by ourselves and can't have any lock
- * conflicts ...
+ * different from the relation's OID. It shouldn't really matter though.
+ * In recovery, we are running by ourselves and can't have any lock
+ * conflicts. While syncing, we already hold AccessExclusiveLock.
*/
rel->rd_lockInfo.lockRelId.dbId = rnode.dbNode;
rel->rd_lockInfo.lockRelId.relId = rnode.relNode;
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b7bcdd9d0f..293ea9a9dd 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -440,6 +440,10 @@ heap_create(const char *relname,
break;
}
}
+ else
+ {
+ rel->rd_createSubid = InvalidSubTransactionId;
+ }
return rel;
}
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 056ea3d5d3..51c233dac6 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -29,9 +29,13 @@
#include "miscadmin.h"
#include "storage/freespace.h"
#include "storage/smgr.h"
+#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "utils/rel.h"
+/* GUC variables */
+int wal_skip_threshold = 64; /* in kilobytes */
+
/*
* We keep a list of all relations (represented as RelFileNode values)
* that have been created or deleted in the current transaction. When
@@ -58,6 +62,7 @@ typedef struct PendingRelDelete
BackendId backend; /* InvalidBackendId if not a temp rel */
bool atCommit; /* T=delete at commit; F=delete at abort */
int nestLevel; /* xact nesting level of request */
+ bool sync; /* whether to fsync at commit */
struct PendingRelDelete *next; /* linked-list link */
} PendingRelDelete;
@@ -114,6 +119,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
pending->backend = backend;
pending->atCommit = false; /* delete if abort */
pending->nestLevel = GetCurrentTransactionNestLevel();
+ pending->sync =
+ relpersistence == RELPERSISTENCE_PERMANENT && !XLogIsNeeded();
pending->next = pendingDeletes;
pendingDeletes = pending;
@@ -155,6 +162,7 @@ RelationDropStorage(Relation rel)
pending->backend = rel->rd_backend;
pending->atCommit = true; /* delete if commit */
pending->nestLevel = GetCurrentTransactionNestLevel();
+ pending->sync = false;
pending->next = pendingDeletes;
pendingDeletes = pending;
@@ -355,7 +363,9 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
/*
* We need to log the copied data in WAL iff WAL archiving/streaming is
- * enabled AND it's a permanent relation.
+ * enabled AND it's a permanent relation. This gives the same answer as
+ * "RelationNeedsWAL(rel) || copying_initfork", because we know the
+ * current operation created a new relfilenode.
*/
use_wal = XLogIsNeeded() &&
(relpersistence == RELPERSISTENCE_PERMANENT || copying_initfork);
@@ -397,24 +407,43 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
}
/*
- * If the rel is WAL-logged, must fsync before commit. We use heap_sync
- * to ensure that the toast table gets fsync'd too. (For a temp or
- * unlogged rel we don't care since the data will be gone after a crash
- * anyway.)
- *
- * It's obvious that we must do this when not WAL-logging the copy. It's
- * less obvious that we have to do it even if we did WAL-log the copied
- * pages. The reason is that since we're copying outside shared buffers, a
- * CHECKPOINT occurring during the copy has no way to flush the previously
- * written data to disk (indeed it won't know the new rel even exists). A
- * crash later on would replay WAL from the checkpoint, therefore it
- * wouldn't replay our earlier WAL entries. If we do not fsync those pages
- * here, they might still not be on disk when the crash occurs.
+ * When we WAL-logged rel pages, we must nonetheless fsync them. The
+ * reason is that since we're copying outside shared buffers, a CHECKPOINT
+ * occurring during the copy has no way to flush the previously written
+ * data to disk (indeed it won't know the new rel even exists). A crash
+ * later on would replay WAL from the checkpoint, therefore it wouldn't
+ * replay our earlier WAL entries. If we do not fsync those pages here,
+ * they might still not be on disk when the crash occurs.
*/
- if (relpersistence == RELPERSISTENCE_PERMANENT || copying_initfork)
+ if (use_wal || copying_initfork)
smgrimmedsync(dst, forkNum);
}
+/*
+ * RelFileNodeSkippingWAL - check if a BM_PERMANENT relfilenode is using WAL
+ *
+ * Changes of certain relfilenodes must not write WAL; see "Skipping WAL for
+ * New RelFileNode" in src/backend/access/transam/README. Though it is
+ * known from Relation efficiently, this function is intended for the code
+ * paths not having access to Relation.
+ */
+bool
+RelFileNodeSkippingWAL(RelFileNode rnode)
+{
+ PendingRelDelete *pending;
+
+ if (XLogIsNeeded())
+ return false; /* no permanent relfilenode skips WAL */
+
+ for (pending = pendingDeletes; pending != NULL; pending = pending->next)
+ {
+ if (RelFileNodeEquals(pending->relnode, rnode) && pending->sync)
+ return true;
+ }
+
+ return false;
+}
+
/*
* smgrDoPendingDeletes() -- Take care of relation deletes at end of xact.
*
@@ -492,6 +521,145 @@ smgrDoPendingDeletes(bool isCommit)
}
}
+/*
+ * smgrDoPendingSyncs() -- Take care of relation syncs at commit.
+ *
+ * This should be called before smgrDoPendingDeletes() at every commit or
+ * prepare. Also this should be called before emitting WAL record so that sync
+ * failure prevents commit.
+ */
+void
+smgrDoPendingSyncs(void)
+{
+ PendingRelDelete *pending;
+ HTAB *delhash = NULL;
+
+ if (XLogIsNeeded())
+ return; /* no relation can use this */
+
+ Assert(GetCurrentTransactionNestLevel() == 1);
+ AssertPendingSyncs_RelationCache();
+
+ /*
+ * Pending syncs on the relation that are to be deleted in this
+ * transaction-end should be ignored. Collect pending deletes that will
+ * happen in the following call to smgrDoPendingDeletes().
+ */
+ for (pending = pendingDeletes; pending != NULL; pending = pending->next)
+ {
+ bool found PG_USED_FOR_ASSERTS_ONLY;
+
+ if (!pending->atCommit)
+ continue;
+
+ /* create the hash if not yet */
+ if (delhash == NULL)
+ {
+ HASHCTL hash_ctl;
+
+ memset(&hash_ctl, 0, sizeof(hash_ctl));
+ hash_ctl.keysize = sizeof(RelFileNode);
+ hash_ctl.entrysize = sizeof(RelFileNode);
+ hash_ctl.hcxt = CurrentMemoryContext;
+ delhash =
+ hash_create("pending del temporary hash", 8, &hash_ctl,
+ HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+ }
+
+ (void) hash_search(delhash, (void *) &pending->relnode,
+ HASH_ENTER, &found);
+ Assert(!found);
+ }
+
+ for (pending = pendingDeletes; pending != NULL; pending = pending->next)
+ {
+ bool to_be_removed = false; /* don't sync if aborted */
+ ForkNumber fork;
+ BlockNumber nblocks[MAX_FORKNUM + 1];
+ BlockNumber total_blocks = 0;
+ SMgrRelation srel;
+
+ if (!pending->sync)
+ continue;
+ Assert(!pending->atCommit);
+
+ /* don't sync relnodes that is being deleted */
+ if (delhash)
+ hash_search(delhash, (void *) &pending->relnode,
+ HASH_FIND, &to_be_removed);
+ if (to_be_removed)
+ continue;
+
+ /* Now the time to sync the rnode */
+ srel = smgropen(pending->relnode, pending->backend);
+
+ /*
+ * We emit newpage WAL records for smaller relations.
+ *
+ * Small WAL records have a chance to be emitted along with other
+ * backends' WAL records. We emit WAL records instead of syncing for
+ * files that are smaller than a certain threshold, expecting faster
+ * commit. The threshold is defined by the GUC wal_skip_threshold.
+ */
+ for (fork = 0 ; fork <= MAX_FORKNUM ; fork++)
+ {
+ if (smgrexists(srel, fork))
+ {
+ BlockNumber n = smgrnblocks(srel, fork);
+
+ /* we shouldn't come here for unlogged relations */
+ Assert(fork != INIT_FORKNUM);
+
+ nblocks[fork] = n;
+ total_blocks += n;
+ }
+ else
+ nblocks[fork] = InvalidBlockNumber;
+ }
+
+ /*
+ * Sync file or emit WAL record for the file according to the total
+ * size.
+ */
+ if (total_blocks * BLCKSZ >= wal_skip_threshold * 1024)
+ {
+ /* Flush all buffers then sync the file */
+ FlushRelationBuffersWithoutRelcache(srel, false);
+
+ for (fork = 0; fork <= MAX_FORKNUM; fork++)
+ {
+ if (smgrexists(srel, fork))
+ smgrimmedsync(srel, fork);
+ }
+ }
+ else
+ {
+ /* Emit WAL records for all blocks. The file is small enough. */
+ for (fork = 0 ; fork <= MAX_FORKNUM ; fork++)
+ {
+ int n = nblocks[fork];
+ Relation rel;
+
+ if (!BlockNumberIsValid(n))
+ continue;
+
+ /*
+ * Emit WAL for the whole file. Unfortunately we don't know
+ * what kind of a page this is, so we have to log the full
+ * page including any unused space. ReadBufferExtended()
+ * counts some pgstat events; unfortunately, we discard them.
+ */
+ rel = CreateFakeRelcacheEntry(srel->smgr_rnode.node);
+ log_newpage_range(rel, fork, 0, n, false);
+ FreeFakeRelcacheEntry(rel);
+ }
+ }
+ }
+
+ if (delhash)
+ hash_destroy(delhash);
+}
+
/*
* smgrGetPendingDeletes() -- Get a list of non-temp relations to be deleted.
*
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index b8c349f245..093fff8c5c 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1014,6 +1014,7 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relfilenode2;
Oid swaptemp;
char swptmpchr;
+ Relation rel1;
/* We need writable copies of both pg_class tuples. */
relRelation = table_open(RelationRelationId, RowExclusiveLock);
@@ -1039,6 +1040,7 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
*/
Assert(!target_is_pg_class);
+ /* swap relfilenodes, reltablespaces, relpersistence */
swaptemp = relform1->relfilenode;
relform1->relfilenode = relform2->relfilenode;
relform2->relfilenode = swaptemp;
@@ -1173,6 +1175,15 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
CacheInvalidateRelcacheByTuple(reltup2);
}
+ /*
+ * Recognize that rel1's relfilenode (swapped from rel2) is new in this
+ * subtransaction. Since the next step for rel2 is deletion, don't bother
+ * recording the newness of its relfilenode.
+ */
+ rel1 = relation_open(r1, AccessExclusiveLock);
+ RelationAssumeNewRelfilenode(rel1);
+ relation_close(rel1, NoLock);
+
/*
* Post alter hook for modified relations. The change to r2 is always
* internal, but r1 depends on the invocation context.
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 42a147b67d..607e2558a3 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -2711,63 +2711,15 @@ CopyFrom(CopyState cstate)
RelationGetRelationName(cstate->rel))));
}
- /*----------
- * Check to see if we can avoid writing WAL
- *
- * If archive logging/streaming is not enabled *and* either
- * - table was created in same transaction as this COPY
- * - data is being written to relfilenode created in this transaction
- * then we can skip writing WAL. It's safe because if the transaction
- * doesn't commit, we'll discard the table (or the new relfilenode file).
- * If it does commit, we'll have done the table_finish_bulk_insert() at
- * the bottom of this routine first.
- *
- * As mentioned in comments in utils/rel.h, the in-same-transaction test
- * is not always set correctly, since in rare cases rd_newRelfilenodeSubid
- * can be cleared before the end of the transaction. The exact case is
- * when a relation sets a new relfilenode twice in same transaction, yet
- * the second one fails in an aborted subtransaction, e.g.
- *
- * BEGIN;
- * TRUNCATE t;
- * SAVEPOINT save;
- * TRUNCATE t;
- * ROLLBACK TO save;
- * COPY ...
- *
- * Also, if the target file is new-in-transaction, we assume that checking
- * FSM for free space is a waste of time, even if we must use WAL because
- * of archiving. This could possibly be wrong, but it's unlikely.
- *
- * The comments for table_tuple_insert and RelationGetBufferForTuple
- * specify that skipping WAL logging is only safe if we ensure that our
- * tuples do not go into pages containing tuples from any other
- * transactions --- but this must be the case if we have a new table or
- * new relfilenode, so we need no additional work to enforce that.
- *
- * We currently don't support this optimization if the COPY target is a
- * partitioned table as we currently only lazily initialize partition
- * information when routing the first tuple to the partition. We cannot
- * know at this stage if we can perform this optimization. It should be
- * possible to improve on this, but it does mean maintaining heap insert
- * option flags per partition and setting them when we first open the
- * partition.
- *
- * This optimization is not supported for relation types which do not
- * have any physical storage, with foreign tables and views using
- * INSTEAD OF triggers entering in this category. Partitioned tables
- * are not supported as per the description above.
- *----------
+ /*
+ * If the target file is new-in-transaction, we assume that checking FSM
+ * for free space is a waste of time. This could possibly be wrong, but
+ * it's unlikely.
*/
- /* createSubid is creation check, newRelfilenodeSubid is truncation check */
if (RELKIND_HAS_STORAGE(cstate->rel->rd_rel->relkind) &&
(cstate->rel->rd_createSubid != InvalidSubTransactionId ||
- cstate->rel->rd_newRelfilenodeSubid != InvalidSubTransactionId))
- {
+ cstate->rel->rd_firstRelfilenodeSubid != InvalidSubTransactionId))
ti_options |= TABLE_INSERT_SKIP_FSM;
- if (!XLogIsNeeded())
- ti_options |= TABLE_INSERT_SKIP_WAL;
- }
/*
* Optimize if new relfilenode was created in this subxact or one of its
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 2bf7083719..20225dc62f 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -552,16 +552,13 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
myState->rel = intoRelationDesc;
myState->reladdr = intoRelationAddr;
myState->output_cid = GetCurrentCommandId(true);
+ myState->ti_options = TABLE_INSERT_SKIP_FSM;
+ myState->bistate = GetBulkInsertState();
/*
- * We can skip WAL-logging the insertions, unless PITR or streaming
- * replication is in use. We can skip the FSM in any case.
+ * Valid smgr_targblock implies something already wrote to the relation.
+ * This may be harmless, but this function hasn't planned for it.
*/
- myState->ti_options = TABLE_INSERT_SKIP_FSM |
- (XLogIsNeeded() ? 0 : TABLE_INSERT_SKIP_WAL);
- myState->bistate = GetBulkInsertState();
-
- /* Not using WAL requires smgr_targblock be initially invalid */
Assert(RelationGetTargetBlock(intoRelationDesc) == InvalidBlockNumber);
}
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 537d0e8cef..ae809c9801 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -457,17 +457,13 @@ transientrel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
*/
myState->transientrel = transientrel;
myState->output_cid = GetCurrentCommandId(true);
-
- /*
- * We can skip WAL-logging the insertions, unless PITR or streaming
- * replication is in use. We can skip the FSM in any case.
- */
myState->ti_options = TABLE_INSERT_SKIP_FSM | TABLE_INSERT_FROZEN;
- if (!XLogIsNeeded())
- myState->ti_options |= TABLE_INSERT_SKIP_WAL;
myState->bistate = GetBulkInsertState();
- /* Not using WAL requires smgr_targblock be initially invalid */
+ /*
+ * Valid smgr_targblock implies something already wrote to the relation.
+ * This may be harmless, but this function hasn't planned for it.
+ */
Assert(RelationGetTargetBlock(transientrel) == InvalidBlockNumber);
}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5440eb9015..0e2f5f4259 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -4770,19 +4770,14 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
newrel = NULL;
/*
- * Prepare a BulkInsertState and options for table_tuple_insert. Because
- * we're building a new heap, we can skip WAL-logging and fsync it to disk
- * at the end instead (unless WAL-logging is required for archiving or
- * streaming replication). The FSM is empty too, so don't bother using it.
+ * Prepare a BulkInsertState and options for table_tuple_insert. The FSM
+ * is empty, so don't bother using it.
*/
if (newrel)
{
mycid = GetCurrentCommandId(true);
bistate = GetBulkInsertState();
-
ti_options = TABLE_INSERT_SKIP_FSM;
- if (!XLogIsNeeded())
- ti_options |= TABLE_INSERT_SKIP_WAL;
}
else
{
@@ -12462,6 +12457,8 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
table_close(pg_class, RowExclusiveLock);
+ RelationAssumeNewRelfilenode(rel);
+
relation_close(rel, NoLock);
/* Make sure the reltablespace change is visible */
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7ad10736d5..746ce477fc 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3203,20 +3203,27 @@ PrintPinnedBufs(void)
void
FlushRelationBuffers(Relation rel)
{
- int i;
- BufferDesc *bufHdr;
-
- /* Open rel at the smgr level if not already done */
RelationOpenSmgr(rel);
- if (RelationUsesLocalBuffers(rel))
+ FlushRelationBuffersWithoutRelcache(rel->rd_smgr,
+ RelationUsesLocalBuffers(rel));
+}
+
+void
+FlushRelationBuffersWithoutRelcache(SMgrRelation smgr, bool islocal)
+{
+ RelFileNode rnode = smgr->smgr_rnode.node;
+ int i;
+ BufferDesc *bufHdr;
+
+ if (islocal)
{
for (i = 0; i < NLocBuffer; i++)
{
uint32 buf_state;
bufHdr = GetLocalBufferDescriptor(i);
- if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node) &&
+ if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
(BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
{
@@ -3233,7 +3240,7 @@ FlushRelationBuffers(Relation rel)
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
- smgrwrite(rel->rd_smgr,
+ smgrwrite(smgr,
bufHdr->tag.forkNum,
bufHdr->tag.blockNum,
localpage,
@@ -3263,18 +3270,18 @@ FlushRelationBuffers(Relation rel)
* As in DropRelFileNodeBuffers, an unlocked precheck should be safe
* and saves some cycles.
*/
- if (!RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
+ if (!RelFileNodeEquals(bufHdr->tag.rnode, rnode))
continue;
ReservePrivateRefCountEntry();
buf_state = LockBufHdr(bufHdr);
- if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node) &&
+ if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
(buf_state & (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
{
PinBuffer_Locked(bufHdr);
LWLockAcquire(BufferDescriptorGetContentLock(bufHdr), LW_SHARED);
- FlushBuffer(bufHdr, rel->rd_smgr);
+ FlushBuffer(bufHdr, smgr);
LWLockRelease(BufferDescriptorGetContentLock(bufHdr));
UnpinBuffer(bufHdr, true);
}
@@ -3484,13 +3491,15 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
{
/*
- * If we're in recovery we cannot dirty a page because of a hint.
- * We can set the hint, just not dirty the page as a result so the
- * hint is lost when we evict the page or shutdown.
+ * If we must not write WAL, due to a relfilenode-specific
+ * condition or being in recovery, don't dirty the page. We can
+ * set the hint, just not dirty the page as a result so the hint
+ * is lost when we evict the page or shutdown.
*
* See src/backend/storage/page/README for longer discussion.
*/
- if (RecoveryInProgress())
+ if (RecoveryInProgress() ||
+ RelFileNodeSkippingWAL(bufHdr->tag.rnode))
return;
/*
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 8a9eaf6430..1d408c339c 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -248,11 +248,10 @@ mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
* During replay, we would delete the file and then recreate it, which is fine
* if the contents of the file were repopulated by subsequent WAL entries.
* But if we didn't WAL-log insertions, but instead relied on fsyncing the
- * file after populating it (as for instance CLUSTER and CREATE INDEX do),
- * the contents of the file would be lost forever. By leaving the empty file
- * until after the next checkpoint, we prevent reassignment of the relfilenode
- * number until it's safe, because relfilenode assignment skips over any
- * existing file.
+ * file after populating it (as we do at wal_level=minimal), the contents of
+ * the file would be lost forever. By leaving the empty file until after the
+ * next checkpoint, we prevent reassignment of the relfilenode number until
+ * it's safe, because relfilenode assignment skips over any existing file.
*
* We do not need to go through this dance for temp relations, though, because
* we never make WAL entries for temp rels, and so a temp rel poses no threat
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ad1ff01b32..f3831f0077 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -262,6 +262,9 @@ static void RelationReloadIndexInfo(Relation relation);
static void RelationReloadNailed(Relation relation);
static void RelationFlushRelation(Relation relation);
static void RememberToFreeTupleDescAtEOX(TupleDesc td);
+#ifdef USE_ASSERT_CHECKING
+static void AssertPendingSyncConsistency(Relation relation);
+#endif
static void AtEOXact_cleanup(Relation relation, bool isCommit);
static void AtEOSubXact_cleanup(Relation relation, bool isCommit,
SubTransactionId mySubid, SubTransactionId parentSubid);
@@ -1095,6 +1098,7 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
relation->rd_isnailed = false;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
+ relation->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
switch (relation->rd_rel->relpersistence)
{
case RELPERSISTENCE_UNLOGGED:
@@ -1828,6 +1832,7 @@ formrdesc(const char *relationName, Oid relationReltype,
relation->rd_isnailed = true;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
+ relation->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
relation->rd_backend = InvalidBackendId;
relation->rd_islocaltemp = false;
@@ -2035,6 +2040,12 @@ RelationIdGetRelation(Oid relationId)
rd = RelationBuildDesc(relationId, true);
if (RelationIsValid(rd))
RelationIncrementReferenceCount(rd);
+
+#ifdef USE_ASSERT_CHECKING
+ if (!XLogIsNeeded() && RelationIsValid(rd))
+ AssertPendingSyncConsistency(rd);
+#endif
+
return rd;
}
@@ -2093,7 +2104,7 @@ RelationClose(Relation relation)
#ifdef RELCACHE_FORCE_RELEASE
if (RelationHasReferenceCountZero(relation) &&
relation->rd_createSubid == InvalidSubTransactionId &&
- relation->rd_newRelfilenodeSubid == InvalidSubTransactionId)
+ relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId)
RelationClearRelation(relation, false);
#endif
}
@@ -2509,13 +2520,13 @@ RelationClearRelation(Relation relation, bool rebuild)
* problem.
*
* When rebuilding an open relcache entry, we must preserve ref count,
- * rd_createSubid/rd_newRelfilenodeSubid, and rd_toastoid state. Also
- * attempt to preserve the pg_class entry (rd_rel), tupledesc,
- * rewrite-rule, partition key, and partition descriptor substructures
- * in place, because various places assume that these structures won't
- * move while they are working with an open relcache entry. (Note:
- * the refcount mechanism for tupledescs might someday allow us to
- * remove this hack for the tupledesc.)
+ * rd_*Subid, and rd_toastoid state. Also attempt to preserve the
+ * pg_class entry (rd_rel), tupledesc, rewrite-rule, partition key,
+ * and partition descriptor substructures in place, because various
+ * places assume that these structures won't move while they are
+ * working with an open relcache entry. (Note: the refcount
+ * mechanism for tupledescs might someday allow us to remove this hack
+ * for the tupledesc.)
*
* Note that this process does not touch CurrentResourceOwner; which
* is good because whatever ref counts the entry may have do not
@@ -2599,6 +2610,7 @@ RelationClearRelation(Relation relation, bool rebuild)
/* creation sub-XIDs must be preserved */
SWAPFIELD(SubTransactionId, rd_createSubid);
SWAPFIELD(SubTransactionId, rd_newRelfilenodeSubid);
+ SWAPFIELD(SubTransactionId, rd_firstRelfilenodeSubid);
/* un-swap rd_rel pointers, swap contents instead */
SWAPFIELD(Form_pg_class, rd_rel);
/* ... but actually, we don't have to update newrel->rd_rel */
@@ -2666,7 +2678,7 @@ static void
RelationFlushRelation(Relation relation)
{
if (relation->rd_createSubid != InvalidSubTransactionId ||
- relation->rd_newRelfilenodeSubid != InvalidSubTransactionId)
+ relation->rd_firstRelfilenodeSubid != InvalidSubTransactionId)
{
/*
* New relcache entries are always rebuilt, not flushed; else we'd
@@ -2751,11 +2763,10 @@ RelationCacheInvalidateEntry(Oid relationId)
* relation cache and re-read relation mapping data.
*
* This is currently used only to recover from SI message buffer overflow,
- * so we do not touch new-in-transaction relations; they cannot be targets
- * of cross-backend SI updates (and our own updates now go through a
- * separate linked list that isn't limited by the SI message buffer size).
- * Likewise, we need not discard new-relfilenode-in-transaction hints,
- * since any invalidation of those would be a local event.
+ * so we do not touch relations having new-in-transaction relfilenodes; they
+ * cannot be targets of cross-backend SI updates (and our own updates now go
+ * through a separate linked list that isn't limited by the SI message
+ * buffer size).
*
* We do this in two phases: the first pass deletes deletable items, and
* the second one rebuilds the rebuildable items. This is essential for
@@ -2806,7 +2817,7 @@ RelationCacheInvalidate(void)
* pending invalidations.
*/
if (relation->rd_createSubid != InvalidSubTransactionId ||
- relation->rd_newRelfilenodeSubid != InvalidSubTransactionId)
+ relation->rd_firstRelfilenodeSubid != InvalidSubTransactionId)
continue;
relcacheInvalsReceived++;
@@ -2918,6 +2929,40 @@ RememberToFreeTupleDescAtEOX(TupleDesc td)
EOXactTupleDescArray[NextEOXactTupleDescNum++] = td;
}
+#ifdef USE_ASSERT_CHECKING
+static void
+AssertPendingSyncConsistency(Relation relation)
+{
+ bool relcache_verdict =
+ relation->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT &&
+ ((relation->rd_createSubid != InvalidSubTransactionId &&
+ RELKIND_HAS_STORAGE(relation->rd_rel->relkind)) ||
+ relation->rd_firstRelfilenodeSubid != InvalidSubTransactionId);
+ Assert(relcache_verdict == RelFileNodeSkippingWAL(relation->rd_node));
+}
+
+/*
+ * AssertPendingSyncs_RelationCache
+ *
+ * Assert that relcache.c and storage.c agree on whether to skip WAL.
+ *
+ * This consistently detects relcache.c skipping WAL while storage.c is not
+ * skipping WAL. It often fails to detect the reverse error, because
+ * invalidation will have destroyed the relcache entry. It will detect the
+ * reverse error if something opens the relation after the DDL.
+ */
+void
+AssertPendingSyncs_RelationCache(void)
+{
+ HASH_SEQ_STATUS status;
+ RelIdCacheEnt *idhentry;
+
+ hash_seq_init(&status, RelationIdCache);
+ while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
+ AssertPendingSyncConsistency(idhentry->reldesc);
+}
+#endif
+
/*
* AtEOXact_RelationCache
*
@@ -3029,10 +3074,7 @@ AtEOXact_cleanup(Relation relation, bool isCommit)
*
* During commit, reset the flag to zero, since we are now out of the
* creating transaction. During abort, simply delete the relcache entry
- * --- it isn't interesting any longer. (NOTE: if we have forgotten the
- * new-ness of a new relation due to a forced cache flush, the entry will
- * get deleted anyway by shared-cache-inval processing of the aborted
- * pg_class insertion.)
+ * --- it isn't interesting any longer.
*/
if (relation->rd_createSubid != InvalidSubTransactionId)
{
@@ -3060,9 +3102,10 @@ AtEOXact_cleanup(Relation relation, bool isCommit)
}
/*
- * Likewise, reset the hint about the relfilenode being new.
+ * Likewise, reset any record of the relfilenode being new.
*/
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
+ relation->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
}
/*
@@ -3154,7 +3197,7 @@ AtEOSubXact_cleanup(Relation relation, bool isCommit,
}
/*
- * Likewise, update or drop any new-relfilenode-in-subtransaction hint.
+ * Likewise, update or drop any new-relfilenode-in-subtransaction.
*/
if (relation->rd_newRelfilenodeSubid == mySubid)
{
@@ -3163,6 +3206,14 @@ AtEOSubXact_cleanup(Relation relation, bool isCommit,
else
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
}
+
+ if (relation->rd_firstRelfilenodeSubid == mySubid)
+ {
+ if (isCommit)
+ relation->rd_firstRelfilenodeSubid = parentSubid;
+ else
+ relation->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
+ }
}
@@ -3252,6 +3303,7 @@ RelationBuildLocalRelation(const char *relname,
/* it's being created in this transaction */
rel->rd_createSubid = GetCurrentSubTransactionId();
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
+ rel->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
/*
* create a new tuple descriptor from the one passed in. We do this
@@ -3549,14 +3601,29 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
*/
CommandCounterIncrement();
- /*
- * Mark the rel as having been given a new relfilenode in the current
- * (sub) transaction. This is a hint that can be used to optimize later
- * operations on the rel in the same transaction.
- */
+ RelationAssumeNewRelfilenode(relation);
+}
+
+/*
+ * RelationAssumeNewRelfilenode
+ *
+ * Code that modifies pg_class.reltablespace or pg_class.relfilenode must call
+ * this. The call shall precede any code that might insert WAL records whose
+ * replay would modify bytes in the new RelFileNode, and the call shall follow
+ * any WAL modifying bytes in the prior RelFileNode. See struct RelationData.
+ * Ideally, call this as near as possible to the CommandCounterIncrement()
+ * that makes the pg_class change visible (before it or after it); that
+ * minimizes the chance of future development adding a forbidden WAL insertion
+ * between RelationAssumeNewRelfilenode() and CommandCounterIncrement().
+ */
+void
+RelationAssumeNewRelfilenode(Relation relation)
+{
relation->rd_newRelfilenodeSubid = GetCurrentSubTransactionId();
+ if (relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId)
+ relation->rd_firstRelfilenodeSubid = relation->rd_newRelfilenodeSubid;
- /* Flag relation as needing eoxact cleanup (to remove the hint) */
+ /* Flag relation as needing eoxact cleanup (to clear these fields) */
EOXactListAdd(relation);
}
@@ -5591,6 +5658,7 @@ load_relcache_init_file(bool shared)
rel->rd_fkeylist = NIL;
rel->rd_createSubid = InvalidSubTransactionId;
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
+ rel->rd_firstRelfilenodeSubid = InvalidSubTransactionId;
rel->rd_amcache = NULL;
MemSet(&rel->pgstat_info, 0, sizeof(rel->pgstat_info));
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ba4edde71a..eecaf398c5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -36,6 +36,7 @@
#include "access/xlog_internal.h"
#include "catalog/namespace.h"
#include "catalog/pg_authid.h"
+#include "catalog/storage.h"
#include "commands/async.h"
#include "commands/prepare.h"
#include "commands/trigger.h"
@@ -2651,6 +2652,18 @@ static struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
+ {
+ {"wal_skip_threshold", PGC_USERSET, RESOURCES_DISK,
+ gettext_noop("Size of new file to fsync instead of writing WAL."),
+ NULL,
+ GUC_UNIT_KB
+ },
+ &wal_skip_threshold,
+ 64,
+ 0, MAX_KILOBYTES,
+ NULL, NULL, NULL
+ },
+
{
{"max_wal_senders", PGC_POSTMASTER, REPLICATION_SENDING,
gettext_noop("Sets the maximum number of simultaneously running WAL sender processes."),
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 858bcb6bc9..22916e8e0e 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -29,7 +29,6 @@
/* "options" flag bits for heap_insert */
-#define HEAP_INSERT_SKIP_WAL TABLE_INSERT_SKIP_WAL
#define HEAP_INSERT_SKIP_FSM TABLE_INSERT_SKIP_FSM
#define HEAP_INSERT_FROZEN TABLE_INSERT_FROZEN
#define HEAP_INSERT_NO_LOGICAL TABLE_INSERT_NO_LOGICAL
@@ -166,8 +165,6 @@ extern void simple_heap_delete(Relation relation, ItemPointer tid);
extern void simple_heap_update(Relation relation, ItemPointer otid,
HeapTuple tup);
-extern void heap_sync(Relation relation);
-
extern TransactionId heap_compute_xid_horizon_for_tuples(Relation rel,
ItemPointerData *items,
int nitems);
diff --git a/src/include/access/rewriteheap.h b/src/include/access/rewriteheap.h
index 8056253916..7f9736e294 100644
--- a/src/include/access/rewriteheap.h
+++ b/src/include/access/rewriteheap.h
@@ -23,7 +23,7 @@ typedef struct RewriteStateData *RewriteState;
extern RewriteState begin_heap_rewrite(Relation OldHeap, Relation NewHeap,
TransactionId OldestXmin, TransactionId FreezeXid,
- MultiXactId MultiXactCutoff, bool use_wal);
+ MultiXactId MultiXactCutoff);
extern void end_heap_rewrite(RewriteState state);
extern void rewrite_heap_tuple(RewriteState state, HeapTuple oldTuple,
HeapTuple newTuple);
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index 64022917e2..aca88d0620 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -127,7 +127,7 @@ typedef struct TM_FailureData
} TM_FailureData;
/* "options" flag bits for table_tuple_insert */
-#define TABLE_INSERT_SKIP_WAL 0x0001
+/* TABLE_INSERT_SKIP_WAL was 0x0001; RelationNeedsWAL() now governs */
#define TABLE_INSERT_SKIP_FSM 0x0002
#define TABLE_INSERT_FROZEN 0x0004
#define TABLE_INSERT_NO_LOGICAL 0x0008
@@ -409,9 +409,8 @@ typedef struct TableAmRoutine
/*
* Perform operations necessary to complete insertions made via
- * tuple_insert and multi_insert with a BulkInsertState specified. This
- * may for example be used to flush the relation, when the
- * TABLE_INSERT_SKIP_WAL option was used.
+ * tuple_insert and multi_insert with a BulkInsertState specified. In-tree
+ * access methods ceased to use this.
*
* Typically callers of tuple_insert and multi_insert will just pass all
* the flags that apply to them, and each AM has to decide which of them
@@ -1087,10 +1086,6 @@ table_compute_xid_horizon_for_tuples(Relation rel,
* The options bitmask allows the caller to specify options that may change the
* behaviour of the AM. The AM will ignore options that it does not support.
*
- * If the TABLE_INSERT_SKIP_WAL option is specified, the new tuple doesn't
- * need to be logged to WAL, even for a non-temp relation. It is the AMs
- * choice whether this optimization is supported.
- *
* If the TABLE_INSERT_SKIP_FSM option is specified, AMs are free to not reuse
* free space in the relation. This can save some cycles when we know the
* relation is new and doesn't contain useful amounts of free space.
@@ -1309,10 +1304,9 @@ table_tuple_lock(Relation rel, ItemPointer tid, Snapshot snapshot,
}
/*
- * Perform operations necessary to complete insertions made via
- * tuple_insert and multi_insert with a BulkInsertState specified. This
- * e.g. may e.g. used to flush the relation when inserting with
- * TABLE_INSERT_SKIP_WAL specified.
+ * Perform operations necessary to complete insertions made via tuple_insert
+ * and multi_insert with a BulkInsertState specified. In-tree access methods
+ * ceased to use this.
*/
static inline void
table_finish_bulk_insert(Relation rel, int options)
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 3579d3f3eb..108115a023 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,18 +19,23 @@
#include "storage/smgr.h"
#include "utils/relcache.h"
+/* GUC variables */
+extern int wal_skip_threshold;
+
extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
extern void RelationDropStorage(Relation rel);
extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
extern void RelationTruncate(Relation rel, BlockNumber nblocks);
extern void RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
ForkNumber forkNum, char relpersistence);
+extern bool RelFileNodeSkippingWAL(RelFileNode rnode);
/*
* These functions used to be in storage/smgr/smgr.c, which explains the
* naming
*/
extern void smgrDoPendingDeletes(bool isCommit);
+extern void smgrDoPendingSyncs(void);
extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
extern void AtSubCommit_smgr(void);
extern void AtSubAbort_smgr(void);
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 17b97f7e38..8097d5ab22 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -49,6 +49,9 @@ typedef enum
/* forward declared, to avoid having to expose buf_internals.h here */
struct WritebackContext;
+/* forward declared, to avoid including smgr.h here */
+struct SMgrRelationData;
+
/* in globals.c ... this duplicates miscadmin.h */
extern PGDLLIMPORT int NBuffers;
@@ -189,6 +192,8 @@ extern BlockNumber RelationGetNumberOfBlocksInFork(Relation relation,
ForkNumber forkNum);
extern void FlushOneBuffer(Buffer buffer);
extern void FlushRelationBuffers(Relation rel);
+extern void FlushRelationBuffersWithoutRelcache(struct SMgrRelationData *smgr,
+ bool islocal);
extern void FlushDatabaseBuffers(Oid dbid);
extern void DropRelFileNodeBuffers(RelFileNodeBackend rnode, ForkNumber *forkNum,
int nforks, BlockNumber *firstDelBlock);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 31d8a1a10e..9db3d23897 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -63,22 +63,40 @@ typedef struct RelationData
* rd_replidindex) */
bool rd_statvalid; /* is rd_statlist valid? */
- /*
+ /*----------
* rd_createSubid is the ID of the highest subtransaction the rel has
- * survived into; or zero if the rel was not created in the current top
- * transaction. This can be now be relied on, whereas previously it could
- * be "forgotten" in earlier releases. Likewise, rd_newRelfilenodeSubid is
- * the ID of the highest subtransaction the relfilenode change has
- * survived into, or zero if not changed in the current transaction (or we
- * have forgotten changing it). rd_newRelfilenodeSubid can be forgotten
- * when a relation has multiple new relfilenodes within a single
- * transaction, with one of them occurring in a subsequently aborted
- * subtransaction, e.g. BEGIN; TRUNCATE t; SAVEPOINT save; TRUNCATE t;
- * ROLLBACK TO save; -- rd_newRelfilenodeSubid is now forgotten
+ * survived into or zero if the rel was not created in the current top
+ * transaction. rd_firstRelfilenodeSubid is the ID of the highest
+ * subtransaction an rd_node change has survived into or zero if rd_node
+ * matches the value it had at the start of the current top transaction.
+ * (Rolling back the subtransaction that rd_firstRelfilenodeSubid denotes
+ * would restore rd_node to the value it had at the start of the current
+ * top transaction. Rolling back any lower subtransaction would not.)
+ * Their accuracy is critical to RelationNeedsWAL().
+ *
+ * rd_newRelfilenodeSubid is the ID of the highest subtransaction the
+ * most-recent relfilenode change has survived into or zero if not changed
+ * in the current transaction (or we have forgotten changing it). This
+ * field is accurate when non-zero, but it can be zero when a relation has
+ * multiple new relfilenodes within a single transaction, with one of them
+ * occurring in a subsequently aborted subtransaction, e.g.
+ * BEGIN;
+ * TRUNCATE t;
+ * SAVEPOINT save;
+ * TRUNCATE t;
+ * ROLLBACK TO save;
+ * -- rd_newRelfilenodeSubid is now forgotten
+ *
+ * These fields are read-only outside relcache.c. Other files trigger
+ * rd_node changes by updating pg_class.reltablespace and/or
+ * pg_class.relfilenode. They must call RelationAssumeNewRelfilenode() to
+ * update these fields.
*/
SubTransactionId rd_createSubid; /* rel was created in current xact */
- SubTransactionId rd_newRelfilenodeSubid; /* new relfilenode assigned in
- * current xact */
+ SubTransactionId rd_newRelfilenodeSubid; /* highest subxact changing
+ * rd_node to current value */
+ SubTransactionId rd_firstRelfilenodeSubid; /* highest subxact changing
+ * rd_node to any value */
Form_pg_class rd_rel; /* RELATION tuple */
TupleDesc rd_att; /* tuple descriptor */
@@ -520,9 +538,16 @@ typedef struct ViewOptions
/*
* RelationNeedsWAL
* True if relation needs WAL.
- */
-#define RelationNeedsWAL(relation) \
- ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT)
+ *
+ * Returns false if wal_level = minimal and this relation is created or
+ * truncated in the current transaction. See "Skipping WAL for New
+ * RelFileNode" in src/backend/access/transam/README.
+ */
+#define RelationNeedsWAL(relation) \
+ ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT && \
+ (XLogIsNeeded() || \
+ (relation->rd_createSubid == InvalidSubTransactionId && \
+ relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId)))
/*
* RelationUsesLocalBuffers
diff --git a/src/include/utils/relcache.h b/src/include/utils/relcache.h
index 2f2ace35b0..d3e8348c1b 100644
--- a/src/include/utils/relcache.h
+++ b/src/include/utils/relcache.h
@@ -105,9 +105,10 @@ extern Relation RelationBuildLocalRelation(const char *relname,
char relkind);
/*
- * Routine to manage assignment of new relfilenode to a relation
+ * Routines to manage assignment of new relfilenode to a relation
*/
extern void RelationSetNewRelfilenode(Relation relation, char persistence);
+extern void RelationAssumeNewRelfilenode(Relation relation);
/*
* Routines for flushing/rebuilding relcache entries in various scenarios
@@ -120,6 +121,11 @@ extern void RelationCacheInvalidate(void);
extern void RelationCloseSmgrByOid(Oid relationId);
+#ifdef USE_ASSERT_CHECKING
+extern void AssertPendingSyncs_RelationCache(void);
+#else
+#define AssertPendingSyncs_RelationCache() do {} while (0)
+#endif
extern void AtEOXact_RelationCache(bool isCommit);
extern void AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid);
diff --git a/src/test/regress/pg_regress.c b/src/test/regress/pg_regress.c
index 297b8fbd6f..1ddde3ecce 100644
--- a/src/test/regress/pg_regress.c
+++ b/src/test/regress/pg_regress.c
@@ -2354,6 +2354,8 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
fputs("log_lock_waits = on\n", pg_conf);
fputs("log_temp_files = 128kB\n", pg_conf);
fputs("max_prepared_transactions = 2\n", pg_conf);
+ fputs("wal_level = minimal\n", pg_conf); /* XXX before commit remove */
+ fputs("max_wal_senders = 0\n", pg_conf);
for (sl = temp_configs; sl != NULL; sl = sl->next)
{
--
2.23.0
From 6b69e19bdae8b282a75ebf373573cdb96adeef06 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyoga.ntt@gmail.com>
Date: Wed, 27 Nov 2019 07:38:46 -0500
Subject: [PATCH v26 2/6] change swap_relation_files
The current patch doesn't adjust the new relation in
swap_relation_files. This inhibits the relcache from
invalidated. Adjust relache of the new relfilenode.
Change lock level for relcache adjusting.
---
src/backend/commands/cluster.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 093fff8c5c..af7733eef4 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1015,6 +1015,7 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
Oid swaptemp;
char swptmpchr;
Relation rel1;
+ Relation rel2;
/* We need writable copies of both pg_class tuples. */
relRelation = table_open(RelationRelationId, RowExclusiveLock);
@@ -1177,12 +1178,31 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
/*
* Recognize that rel1's relfilenode (swapped from rel2) is new in this
- * subtransaction. Since the next step for rel2 is deletion, don't bother
- * recording the newness of its relfilenode.
+ * subtransaction. However the next step for rel2 is deletion, we need to
+ * turn off the newness of its relfilenode, that allows the relcache to be
+ * flushed. Requried lock must be held before getting here so we take
+ * AccessShareLock in case no lock is acquired. Since command counter is
+ * not advanced the relcache entries has the contens before the above
+ * updates. We don't bother incrementing it and swap their contents
+ * directly.
+ */
+ rel1 = relation_open(r1, AccessShareLock);
+ rel2 = relation_open(r2, AccessShareLock);
+
+ /* swap relfilenodes */
+ rel1->rd_node.relNode = relfilenode2;
+ rel2->rd_node.relNode = relfilenode1;
+
+ /*
+ * Adjust newness flags. relfilenode2 is already added to EOXact array so
+ * we don't need to do that again here. We assume the new file is created
+ * in the current subtransaction.
*/
- rel1 = relation_open(r1, AccessExclusiveLock);
RelationAssumeNewRelfilenode(rel1);
- relation_close(rel1, NoLock);
+ rel2->rd_createSubid = InvalidSubTransactionId;
+
+ relation_close(rel1, AccessShareLock);
+ relation_close(rel2, AccessShareLock);
/*
* Post alter hook for modified relations. The change to r2 is always
--
2.23.0
From 061e02878dcb3e2a6a54afb591dfec2f3ef88550 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 21 Nov 2019 19:33:18 +0900
Subject: [PATCH v26 3/6] Improve the performance of relation syncs.
We can improve performance of syncing multiple files at once in the
same way as b41669118. This reduces the number of scans on the whole
shared_bufffers from the number of synced relations to one.
---
src/backend/catalog/storage.c | 28 +++++--
src/backend/storage/buffer/bufmgr.c | 113 ++++++++++++++++++++++++++++
src/backend/storage/smgr/smgr.c | 37 +++++++++
src/include/storage/bufmgr.h | 1 +
src/include/storage/smgr.h | 1 +
5 files changed, 174 insertions(+), 6 deletions(-)
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 51c233dac6..65811b2a9e 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -533,6 +533,9 @@ smgrDoPendingSyncs(void)
{
PendingRelDelete *pending;
HTAB *delhash = NULL;
+ int nrels = 0,
+ maxrels = 0;
+ SMgrRelation *srels = NULL;
if (XLogIsNeeded())
return; /* no relation can use this */
@@ -573,7 +576,7 @@ smgrDoPendingSyncs(void)
for (pending = pendingDeletes; pending != NULL; pending = pending->next)
{
- bool to_be_removed = false; /* don't sync if aborted */
+ bool to_be_removed = false;
ForkNumber fork;
BlockNumber nblocks[MAX_FORKNUM + 1];
BlockNumber total_blocks = 0;
@@ -623,14 +626,21 @@ smgrDoPendingSyncs(void)
*/
if (total_blocks * BLCKSZ >= wal_skip_threshold * 1024)
{
- /* Flush all buffers then sync the file */
- FlushRelationBuffersWithoutRelcache(srel, false);
+ /* relations to sync are passed to smgrdosyncall at once */
- for (fork = 0; fork <= MAX_FORKNUM; fork++)
+ /* allocate the initial array, or extend it, if needed */
+ if (maxrels == 0)
{
- if (smgrexists(srel, fork))
- smgrimmedsync(srel, fork);
+ maxrels = 8;
+ srels = palloc(sizeof(SMgrRelation) * maxrels);
}
+ else if (maxrels <= nrels)
+ {
+ maxrels *= 2;
+ srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+ }
+
+ srels[nrels++] = srel;
}
else
{
@@ -658,6 +668,12 @@ smgrDoPendingSyncs(void)
if (delhash)
hash_destroy(delhash);
+
+ if (nrels > 0)
+ {
+ smgrdosyncall(srels, nrels);
+ pfree(srels);
+ }
}
/*
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 746ce477fc..e0c0b825e9 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -105,6 +105,19 @@ typedef struct CkptTsStatus
int index;
} CkptTsStatus;
+/*
+ * Type for array used to sort SMgrRelations
+ *
+ * FlushRelFileNodesAllBuffers shares the same comparator function with
+ * DropRelFileNodeBuffers. Pointer to this struct and RelFileNode must
+ * be compatible.
+ */
+typedef struct SMgrSortArray
+{
+ RelFileNode rnode; /* This must be the first member */
+ SMgrRelation srel;
+} SMgrSortArray;
+
/* GUC variables */
bool zero_damaged_pages = false;
int bgwriter_lru_maxpages = 100;
@@ -3290,6 +3303,106 @@ FlushRelationBuffersWithoutRelcache(SMgrRelation smgr, bool islocal)
}
}
+/* ---------------------------------------------------------------------
+ * FlushRelFileNodesAllBuffers
+ *
+ * This function flushes out the buffer pool all the pages of all
+ * forks of the specified smgr relations. It's equivalent to
+ * calling FlushRelationBuffers once per fork per relation, but the
+ * parameter is not Relation but SMgrRelation
+ * --------------------------------------------------------------------
+ */
+void
+FlushRelFileNodesAllBuffers(SMgrRelation *smgrs, int nrels)
+{
+ int i;
+ SMgrSortArray *srels;
+ bool use_bsearch;
+
+ if (nrels == 0)
+ return;
+
+ /* fill-in array for qsort */
+ srels = palloc(sizeof(SMgrSortArray) * nrels);
+
+ for (i = 0 ; i < nrels ; i++)
+ {
+ Assert (!RelFileNodeBackendIsTemp(smgrs[i]->smgr_rnode));
+
+ srels[i].rnode = smgrs[i]->smgr_rnode.node;
+ srels[i].srel = smgrs[i];
+ }
+
+ /*
+ * Save the bsearch overhead for low number of relations to
+ * sync. See DropRelFileNodesAllBuffers for details. The name DROP_*
+ * is for historical reasons.
+ */
+ use_bsearch = nrels > DROP_RELS_BSEARCH_THRESHOLD;
+
+ /* sort the list of SMgrRelations if necessary */
+ if (use_bsearch)
+ pg_qsort(srels, nrels, sizeof(SMgrSortArray), rnode_comparator);
+
+ /* Make sure we can handle the pin inside the loop */
+ ResourceOwnerEnlargeBuffers(CurrentResourceOwner);
+
+ for (i = 0; i < NBuffers; i++)
+ {
+ SMgrSortArray *srelent = NULL;
+ BufferDesc *bufHdr = GetBufferDescriptor(i);
+ uint32 buf_state;
+
+ /*
+ * As in DropRelFileNodeBuffers, an unlocked precheck should be safe
+ * and saves some cycles.
+ */
+
+ if (!use_bsearch)
+ {
+ int j;
+
+ for (j = 0; j < nrels; j++)
+ {
+ if (RelFileNodeEquals(bufHdr->tag.rnode, srels[j].rnode))
+ {
+ srelent = &srels[j];
+ break;
+ }
+ }
+
+ }
+ else
+ {
+ srelent = bsearch((const void *) &(bufHdr->tag.rnode),
+ srels, nrels, sizeof(SMgrSortArray),
+ rnode_comparator);
+ }
+
+ /* buffer doesn't belong to any of the given relfilenodes; skip it */
+ if (srelent == NULL)
+ continue;
+
+ /* Ensure there's a free array slot for PinBuffer_Locked */
+ ReservePrivateRefCountEntry();
+
+ buf_state = LockBufHdr(bufHdr);
+ if (RelFileNodeEquals(bufHdr->tag.rnode, srelent->rnode) &&
+ (buf_state & (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
+ {
+ PinBuffer_Locked(bufHdr);
+ LWLockAcquire(BufferDescriptorGetContentLock(bufHdr), LW_SHARED);
+ FlushBuffer(bufHdr, srelent->srel);
+ LWLockRelease(BufferDescriptorGetContentLock(bufHdr));
+ UnpinBuffer(bufHdr, true);
+ }
+ else
+ UnlockBufHdr(bufHdr, buf_state);
+ }
+
+ pfree(srels);
+}
+
/* ---------------------------------------------------------------------
* FlushDatabaseBuffers
*
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index b50c69b438..191b52ab43 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -388,6 +388,43 @@ smgrdounlink(SMgrRelation reln, bool isRedo)
smgrsw[which].smgr_unlink(rnode, InvalidForkNumber, isRedo);
}
+/*
+ * smgrdosyncall() -- Immediately sync all forks of all given relations
+ *
+ * All forks of all given relations are syncd out to the store.
+ *
+ * This is equivalent to flusing all buffers FlushRelationBuffers for each
+ * smgr relation then calling smgrimmedsync for all forks of each smgr
+ * relation, but it's significantly quicker so should be preferred when
+ * possible.
+ */
+void
+smgrdosyncall(SMgrRelation *rels, int nrels)
+{
+ int i = 0;
+ ForkNumber forknum;
+
+ if (nrels == 0)
+ return;
+
+ /* We need to flush all buffers for the relations before sync. */
+ FlushRelFileNodesAllBuffers(rels, nrels);
+
+ /*
+ * Sync the physical file(s).
+ */
+ for (i = 0; i < nrels; i++)
+ {
+ int which = rels[i]->smgr_which;
+
+ for (forknum = 0; forknum <= MAX_FORKNUM; forknum++)
+ {
+ if (smgrsw[which].smgr_exists(rels[i], forknum))
+ smgrsw[which].smgr_immedsync(rels[i], forknum);
+ }
+ }
+}
+
/*
* smgrdounlinkall() -- Immediately unlink all forks of all given relations
*
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 8097d5ab22..558bac7e05 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -197,6 +197,7 @@ extern void FlushRelationBuffersWithoutRelcache(struct SMgrRelationData *smgr,
extern void FlushDatabaseBuffers(Oid dbid);
extern void DropRelFileNodeBuffers(RelFileNodeBackend rnode, ForkNumber *forkNum,
int nforks, BlockNumber *firstDelBlock);
+extern void FlushRelFileNodesAllBuffers(struct SMgrRelationData **smgrs, int nrels);
extern void DropRelFileNodesAllBuffers(RelFileNodeBackend *rnodes, int nnodes);
extern void DropDatabaseBuffers(Oid dbid);
diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index 1543d8d870..31a5ecd059 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -89,6 +89,7 @@ extern void smgrcloseall(void);
extern void smgrclosenode(RelFileNodeBackend rnode);
extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
extern void smgrdounlink(SMgrRelation reln, bool isRedo);
+extern void smgrdosyncall(SMgrRelation *rels, int nrels);
extern void smgrdounlinkall(SMgrRelation *rels, int nrels, bool isRedo);
extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
BlockNumber blocknum, char *buffer, bool skipFsync);
--
2.23.0
From 25aa85b8b0c0b329de6b84942759797bfc912461 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 21 Nov 2019 19:28:35 +0900
Subject: [PATCH v26 4/6] Revert FlushRelationBuffersWithoutRelcache.
The previous patch makes the function useless. Revert it.
---
src/backend/storage/buffer/bufmgr.c | 27 ++++++++++-----------------
src/include/storage/bufmgr.h | 2 --
2 files changed, 10 insertions(+), 19 deletions(-)
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index e0c0b825e9..56314653ae 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3216,27 +3216,20 @@ PrintPinnedBufs(void)
void
FlushRelationBuffers(Relation rel)
{
- RelationOpenSmgr(rel);
-
- FlushRelationBuffersWithoutRelcache(rel->rd_smgr,
- RelationUsesLocalBuffers(rel));
-}
-
-void
-FlushRelationBuffersWithoutRelcache(SMgrRelation smgr, bool islocal)
-{
- RelFileNode rnode = smgr->smgr_rnode.node;
- int i;
+ int i;
BufferDesc *bufHdr;
- if (islocal)
+ /* Open rel at the smgr level if not already done */
+ RelationOpenSmgr(rel);
+
+ if (RelationUsesLocalBuffers(rel))
{
for (i = 0; i < NLocBuffer; i++)
{
uint32 buf_state;
bufHdr = GetLocalBufferDescriptor(i);
- if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
+ if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node) &&
((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
(BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
{
@@ -3253,7 +3246,7 @@ FlushRelationBuffersWithoutRelcache(SMgrRelation smgr, bool islocal)
PageSetChecksumInplace(localpage, bufHdr->tag.blockNum);
- smgrwrite(smgr,
+ smgrwrite(rel->rd_smgr,
bufHdr->tag.forkNum,
bufHdr->tag.blockNum,
localpage,
@@ -3283,18 +3276,18 @@ FlushRelationBuffersWithoutRelcache(SMgrRelation smgr, bool islocal)
* As in DropRelFileNodeBuffers, an unlocked precheck should be safe
* and saves some cycles.
*/
- if (!RelFileNodeEquals(bufHdr->tag.rnode, rnode))
+ if (!RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node))
continue;
ReservePrivateRefCountEntry();
buf_state = LockBufHdr(bufHdr);
- if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
+ if (RelFileNodeEquals(bufHdr->tag.rnode, rel->rd_node) &&
(buf_state & (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
{
PinBuffer_Locked(bufHdr);
LWLockAcquire(BufferDescriptorGetContentLock(bufHdr), LW_SHARED);
- FlushBuffer(bufHdr, smgr);
+ FlushBuffer(bufHdr, rel->rd_smgr);
LWLockRelease(BufferDescriptorGetContentLock(bufHdr));
UnpinBuffer(bufHdr, true);
}
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index 558bac7e05..3f85e8c6fe 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -192,8 +192,6 @@ extern BlockNumber RelationGetNumberOfBlocksInFork(Relation relation,
ForkNumber forkNum);
extern void FlushOneBuffer(Buffer buffer);
extern void FlushRelationBuffers(Relation rel);
-extern void FlushRelationBuffersWithoutRelcache(struct SMgrRelationData *smgr,
- bool islocal);
extern void FlushDatabaseBuffers(Oid dbid);
extern void DropRelFileNodeBuffers(RelFileNodeBackend rnode, ForkNumber *forkNum,
int nforks, BlockNumber *firstDelBlock);
--
2.23.0
From 29af080eb433af96baf0e64de0dcbded7a128263 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 21 Nov 2019 16:12:03 +0900
Subject: [PATCH v26 5/6] Fix gistGetFakeLSN()
GiST needs to set page LSN to monotically incresing numbers on updates
even if it is not WAL-logged at all. We use a simple counter for
UNLOGGESD/TEMP relations but the number must be smaller than the LSN
at the next commit for WAL-skipped relations. WAL-insertione pointer
works in major cases but we sometimes need to emit a WAL record to
generate an unique LSN for update. This patch adds a new WAL record
kind XLOG_GIST_ASSIGN_LSN, which conveys no substantial content and
emits it if needed.
---
src/backend/access/gist/gistutil.c | 38 ++++++++++++++++++--------
src/backend/access/gist/gistxlog.c | 21 ++++++++++++++
src/backend/access/rmgrdesc/gistdesc.c | 5 ++++
src/include/access/gist_private.h | 2 ++
src/include/access/gistxlog.h | 1 +
5 files changed, 56 insertions(+), 11 deletions(-)
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 66c52d6dd6..8347673c5e 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1004,28 +1004,44 @@ gistproperty(Oid index_oid, int attno,
}
/*
- * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
- * to detect concurrent page splits anyway. This function provides a fake
- * sequence of LSNs for that purpose.
+ * Temporary, unlogged GiST and WAL-skipped indexes are not WAL-logged, but we
+ * need LSNs to detect concurrent page splits anyway. This function provides a
+ * fake sequence of LSNs for that purpose.
*/
XLogRecPtr
gistGetFakeLSN(Relation rel)
{
- static XLogRecPtr counter = FirstNormalUnloggedLSN;
-
- /*
- * XXX before commit fix this. This is not correct for
- * RELPERSISTENCE_PERMANENT, but it suffices to make tests pass.
- */
- if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP
- || rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT)
+ if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
{
/*
* Temporary relations are only accessible in our session, so a simple
* backend-local counter will do.
*/
+ static XLogRecPtr counter = FirstNormalUnloggedLSN;
+
return counter++;
}
+ else if (rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT)
+ {
+ /*
+ * WAL-logging on this relation will start after commit, so the LSN
+ * must be distinct numbers smaller than the LSN at the next
+ * commit. Emit a dummy WAL record if insert-LSN hasn't advanced after
+ * the last call.
+ */
+ static XLogRecPtr lastlsn = InvalidXLogRecPtr;
+ XLogRecPtr currlsn = GetXLogInsertRecPtr();
+
+ /* Shouldn't be called for WAL-logging relations */
+ Assert(!RelationNeedsWAL(rel));
+
+ /* No need for an actual record if we alredy have a distinct LSN */
+ if (!XLogRecPtrIsInvalid(lastlsn) && lastlsn == currlsn)
+ currlsn = gistXLogAssignLSN();
+
+ lastlsn = currlsn;
+ return currlsn;
+ }
else
{
/*
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index 3b28f54646..ce17bc9dc3 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -449,6 +449,9 @@ gist_redo(XLogReaderState *record)
case XLOG_GIST_PAGE_DELETE:
gistRedoPageDelete(record);
break;
+ case XLOG_GIST_ASSIGN_LSN:
+ /* nop. See gistGetFakeLSN(). */
+ break;
default:
elog(PANIC, "gist_redo: unknown op code %u", info);
}
@@ -592,6 +595,24 @@ gistXLogPageDelete(Buffer buffer, FullTransactionId xid,
return recptr;
}
+/*
+ * Write an empty XLOG record to assign a distinct LSN.
+ */
+XLogRecPtr
+gistXLogAssignLSN(void)
+{
+ int dummy = 0;
+
+ /*
+ * Records other than SWITCH_WAL must have content. We use an integer 0 to
+ * follow the restriction.
+ */
+ XLogBeginInsert();
+ XLogSetRecordFlags(XLOG_MARK_UNIMPORTANT);
+ XLogRegisterData((char*) &dummy, sizeof(dummy));
+ return XLogInsert(RM_GIST_ID, XLOG_GIST_ASSIGN_LSN);
+}
+
/*
* Write XLOG record about reuse of a deleted page.
*/
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index eccb6fd942..48cda40ac0 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -80,6 +80,9 @@ gist_desc(StringInfo buf, XLogReaderState *record)
case XLOG_GIST_PAGE_DELETE:
out_gistxlogPageDelete(buf, (gistxlogPageDelete *) rec);
break;
+ case XLOG_GIST_ASSIGN_LSN:
+ /* No details to write out */
+ break;
}
}
@@ -104,6 +107,8 @@ gist_identify(uint8 info)
break;
case XLOG_GIST_PAGE_DELETE:
id = "PAGE_DELETE";
+ case XLOG_GIST_ASSIGN_LSN:
+ id = "ASSIGN_LSN";
break;
}
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index a409975db1..3455dd242d 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -455,6 +455,8 @@ extern XLogRecPtr gistXLogSplit(bool page_is_leaf,
BlockNumber origrlink, GistNSN oldnsn,
Buffer leftchild, bool markfollowright);
+extern XLogRecPtr gistXLogAssignLSN(void);
+
/* gistget.c */
extern bool gistgettuple(IndexScanDesc scan, ScanDirection dir);
extern int64 gistgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index e44922d915..1eae06c0fb 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -26,6 +26,7 @@
/* #define XLOG_GIST_INSERT_COMPLETE 0x40 */ /* not used anymore */
/* #define XLOG_GIST_CREATE_INDEX 0x50 */ /* not used anymore */
#define XLOG_GIST_PAGE_DELETE 0x60
+#define XLOG_GIST_ASSIGN_LSN 0x70 /* nop, assign an new LSN */
/*
* Backup Blk 0: updated page.
--
2.23.0
From 70d8236c375c6dc115e6023707b8a53a28f0b872 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Tue, 26 Nov 2019 21:25:09 +0900
Subject: [PATCH v26 6/6] Sync files shrinked by truncation
If truncation made a WAL-skipped file become smaller at commit than
the maximum size during the transaction, the file must not be
at-commit-WAL-logged and must be synced.
---
src/backend/access/transam/xact.c | 5 +-
src/backend/catalog/storage.c | 161 +++++++++++++++++++-----------
src/include/catalog/storage.h | 2 +-
3 files changed, 106 insertions(+), 62 deletions(-)
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 750f95c482..f681cd3a23 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2114,7 +2114,7 @@ CommitTransaction(void)
* transaction. This must happen before AtEOXact_RelationMap(), so that we
* don't see committed-but-broken files after a crash.
*/
- smgrDoPendingSyncs();
+ smgrDoPendingSyncs(true);
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
@@ -2354,7 +2354,7 @@ PrepareTransaction(void)
* transaction. This must happen before EndPrepare(), so that we don't see
* committed-but-broken files after a crash and COMMIT PREPARED.
*/
- smgrDoPendingSyncs();
+ smgrDoPendingSyncs(true);
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
@@ -2674,6 +2674,7 @@ AbortTransaction(void)
*/
AfterTriggerEndXact(false); /* 'false' means it's abort */
AtAbort_Portals();
+ smgrDoPendingSyncs(false);
AtEOXact_LargeObject(false);
AtAbort_Notify();
AtEOXact_RelationMap(false, is_parallel_worker);
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 65811b2a9e..aa68c77d44 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -62,11 +62,17 @@ typedef struct PendingRelDelete
BackendId backend; /* InvalidBackendId if not a temp rel */
bool atCommit; /* T=delete at commit; F=delete at abort */
int nestLevel; /* xact nesting level of request */
- bool sync; /* whether to fsync at commit */
struct PendingRelDelete *next; /* linked-list link */
} PendingRelDelete;
+typedef struct pendingSync
+{
+ RelFileNode rnode;
+ BlockNumber max_truncated;
+} pendingSync;
+
static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
+HTAB *pendingSyncHash = NULL;
/*
* RelationCreateStorage
@@ -119,11 +125,39 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
pending->backend = backend;
pending->atCommit = false; /* delete if abort */
pending->nestLevel = GetCurrentTransactionNestLevel();
- pending->sync =
- relpersistence == RELPERSISTENCE_PERMANENT && !XLogIsNeeded();
pending->next = pendingDeletes;
pendingDeletes = pending;
+ /*
+ * If the relation needs at-commit sync, we also need to track the maximum
+ * unsynced truncated block used to decide whether we can WAL-logging or we
+ * must sync the file in smgrDoPendingSyncs.
+ */
+ if (relpersistence == RELPERSISTENCE_PERMANENT && !XLogIsNeeded())
+ {
+ pendingSync *pending;
+ bool found;
+
+ /* we sync only permanent relations */
+ Assert(backend == InvalidBackendId);
+
+ if (!pendingSyncHash)
+ {
+ HASHCTL ctl;
+
+ ctl.keysize = sizeof(RelFileNode);
+ ctl.entrysize = sizeof(pendingSync);
+ ctl.hcxt = TopTransactionContext;
+ pendingSyncHash =
+ hash_create("max truncatd block hash",
+ 16, &ctl, HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+ }
+
+ pending = hash_search(pendingSyncHash, &rnode, HASH_ENTER, &found);
+ Assert(!found);
+ pending->max_truncated = InvalidBlockNumber;
+ }
+
return srel;
}
@@ -162,7 +196,6 @@ RelationDropStorage(Relation rel)
pending->backend = rel->rd_backend;
pending->atCommit = true; /* delete if commit */
pending->nestLevel = GetCurrentTransactionNestLevel();
- pending->sync = false;
pending->next = pendingDeletes;
pendingDeletes = pending;
@@ -320,6 +353,22 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
if (fsm || vm)
XLogFlush(lsn);
}
+ else if (pendingSyncHash)
+ {
+ pendingSync *pending;
+
+ /* Record largest maybe-unsynced block of files under tracking */
+ pending = hash_search(pendingSyncHash, &(rel->rd_smgr->smgr_rnode.node),
+ HASH_FIND, NULL);
+ if (pending)
+ {
+ BlockNumber nblocks = smgrnblocks(rel->rd_smgr, MAIN_FORKNUM);
+
+ if (!BlockNumberIsValid(pending->max_truncated) ||
+ pending->max_truncated < nblocks)
+ pending->max_truncated = nblocks;
+ }
+ }
/* Do the real work to truncate relation forks */
smgrtruncate(rel->rd_smgr, forks, nforks, blocks);
@@ -430,18 +479,17 @@ RelationCopyStorage(SMgrRelation src, SMgrRelation dst,
bool
RelFileNodeSkippingWAL(RelFileNode rnode)
{
- PendingRelDelete *pending;
-
if (XLogIsNeeded())
return false; /* no permanent relfilenode skips WAL */
- for (pending = pendingDeletes; pending != NULL; pending = pending->next)
- {
- if (RelFileNodeEquals(pending->relnode, rnode) && pending->sync)
- return true;
- }
+ if (!pendingSyncHash)
+ return false; /* we don't have a to-be-synced relation */
- return false;
+ /* the relation is not tracked as to-be-synced */
+ if (hash_search(pendingSyncHash, &rnode, HASH_FIND, NULL) == NULL)
+ return false;
+
+ return true;
}
/*
@@ -529,13 +577,14 @@ smgrDoPendingDeletes(bool isCommit)
* failure prevents commit.
*/
void
-smgrDoPendingSyncs(void)
+smgrDoPendingSyncs(bool isCommit)
{
PendingRelDelete *pending;
- HTAB *delhash = NULL;
int nrels = 0,
maxrels = 0;
SMgrRelation *srels = NULL;
+ HASH_SEQ_STATUS scan;
+ pendingSync *pendingsync;
if (XLogIsNeeded())
return; /* no relation can use this */
@@ -543,58 +592,44 @@ smgrDoPendingSyncs(void)
Assert(GetCurrentTransactionNestLevel() == 1);
AssertPendingSyncs_RelationCache();
+ if (!pendingSyncHash)
+ return; /* no relation needs sync */
+
+ /* Just throw away all pending syncs if any at rollback */
+ if (!isCommit)
+ {
+ if (pendingSyncHash)
+ {
+ hash_destroy(pendingSyncHash);
+ pendingSyncHash = NULL;
+ }
+ return;
+ }
+
/*
* Pending syncs on the relation that are to be deleted in this
- * transaction-end should be ignored. Collect pending deletes that will
- * happen in the following call to smgrDoPendingDeletes().
+ * transaction-end should be ignored. Remove sync hash entries entries for
+ * relations that will be deleted in the following call to
+ * smgrDoPendingDeletes().
*/
for (pending = pendingDeletes; pending != NULL; pending = pending->next)
{
- bool found PG_USED_FOR_ASSERTS_ONLY;
-
if (!pending->atCommit)
continue;
- /* create the hash if not yet */
- if (delhash == NULL)
- {
- HASHCTL hash_ctl;
-
- memset(&hash_ctl, 0, sizeof(hash_ctl));
- hash_ctl.keysize = sizeof(RelFileNode);
- hash_ctl.entrysize = sizeof(RelFileNode);
- hash_ctl.hcxt = CurrentMemoryContext;
- delhash =
- hash_create("pending del temporary hash", 8, &hash_ctl,
- HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
- }
-
- (void) hash_search(delhash, (void *) &pending->relnode,
- HASH_ENTER, &found);
- Assert(!found);
+ (void) hash_search(pendingSyncHash, (void *) &pending->relnode,
+ HASH_REMOVE, NULL);
}
- for (pending = pendingDeletes; pending != NULL; pending = pending->next)
+ hash_seq_init(&scan, pendingSyncHash);
+ while ((pendingsync = (pendingSync *) hash_seq_search(&scan)))
{
- bool to_be_removed = false;
- ForkNumber fork;
- BlockNumber nblocks[MAX_FORKNUM + 1];
- BlockNumber total_blocks = 0;
- SMgrRelation srel;
-
- if (!pending->sync)
- continue;
- Assert(!pending->atCommit);
-
- /* don't sync relnodes that is being deleted */
- if (delhash)
- hash_search(delhash, (void *) &pending->relnode,
- HASH_FIND, &to_be_removed);
- if (to_be_removed)
- continue;
+ ForkNumber fork;
+ BlockNumber nblocks[MAX_FORKNUM + 1];
+ BlockNumber total_blocks = 0;
+ SMgrRelation srel;
- /* Now the time to sync the rnode */
- srel = smgropen(pending->relnode, pending->backend);
+ srel = smgropen(pendingsync->rnode, InvalidBackendId);
/*
* We emit newpage WAL records for smaller relations.
@@ -622,9 +657,12 @@ smgrDoPendingSyncs(void)
/*
* Sync file or emit WAL record for the file according to the total
- * size.
+ * size. Do file sync if the size is larger than the threshold or
+ * truncates may have left blocks beyond the current size.
*/
- if (total_blocks * BLCKSZ >= wal_skip_threshold * 1024)
+ if (total_blocks * BLCKSZ >= wal_skip_threshold * 1024 ||
+ (BlockNumberIsValid(pendingsync->max_truncated) &&
+ smgrnblocks(srel, MAIN_FORKNUM) < pendingsync->max_truncated))
{
/* relations to sync are passed to smgrdosyncall at once */
@@ -644,7 +682,11 @@ smgrDoPendingSyncs(void)
}
else
{
- /* Emit WAL records for all blocks. The file is small enough. */
+ /*
+ * Emit WAL records for all blocks. We don't emit
+ * XLOG_SMGR_TRUNCATE record because the past truncations haven't
+ * left unlogged pages here.
+ */
for (fork = 0 ; fork <= MAX_FORKNUM ; fork++)
{
int n = nblocks[fork];
@@ -666,8 +708,9 @@ smgrDoPendingSyncs(void)
}
}
- if (delhash)
- hash_destroy(delhash);
+ Assert (pendingSyncHash);
+ hash_destroy(pendingSyncHash);
+ pendingSyncHash = NULL;
if (nrels > 0)
{
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 108115a023..bf076657e7 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -35,7 +35,7 @@ extern bool RelFileNodeSkippingWAL(RelFileNode rnode);
* naming
*/
extern void smgrDoPendingDeletes(bool isCommit);
-extern void smgrDoPendingSyncs(void);
+extern void smgrDoPendingSyncs(bool isCommit);
extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
extern void AtSubCommit_smgr(void);
extern void AtSubAbort_smgr(void);
--
2.23.0
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