Re: Removal of temp tables - Mailing list pgsql-patches

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > I am wondering if pg_temp tables should even be seen as system tables by
> > IsSystemRelationName().  We have to call them pg_ so user applications
> > don't display them, but other than that they aren't like system tables.
> > Comments?
>
> This oughta be discussed on pghackers, not just -patches.  But my
> thought is that we need a three-way distinction; at least some of the
> IsSystemRelation checks presumably *should* accept temp relnames, else
> we'd not have decided to do it that way in the first place.
>
> Another point is that when we implement schemas (= Real Soon Now, I
> trust), the whole business of temprels having different physical and
> logical relnames will go away anyhow.  Temp rels will become plain rels
> that live in a temp schema.  So it may not be worth adding further
> complexity to support the present approach.  We'll just have to rip
> it out again ... better to expend the work on making schemas.

Here is an updated patch that uses underscores in temp table names so
the DROP doesn't have to quote the table name:

    pg_temp_7199_0

I will apply this in two days if there are no other comments.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
Index: src/backend/catalog/aclchk.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/catalog/aclchk.c,v
retrieving revision 1.50
diff -c -r1.50 aclchk.c
*** src/backend/catalog/aclchk.c    2001/06/09 23:21:54    1.50
--- src/backend/catalog/aclchk.c    2001/06/14 16:33:47
***************
*** 32,37 ****
--- 32,38 ----
  #include "parser/parse_func.h"
  #include "utils/acl.h"
  #include "utils/syscache.h"
+ #include "utils/temprel.h"

  static int32 aclcheck(Acl *acl, AclId id, AclIdType idtype, AclMode mode);

***************
*** 437,443 ****
       */
      if ((mode & (ACL_INSERT | ACL_UPDATE | ACL_DELETE)) &&
          !allowSystemTableMods && IsSystemRelationName(relname) &&
!         strncmp(relname, "pg_temp.", strlen("pg_temp.")) != 0 &&
          !((Form_pg_shadow) GETSTRUCT(tuple))->usecatupd)
      {
  #ifdef ACLDEBUG
--- 438,444 ----
       */
      if ((mode & (ACL_INSERT | ACL_UPDATE | ACL_DELETE)) &&
          !allowSystemTableMods && IsSystemRelationName(relname) &&
!         !is_temp_relname(relname) &&
          !((Form_pg_shadow) GETSTRUCT(tuple))->usecatupd)
      {
  #ifdef ACLDEBUG
Index: src/backend/catalog/heap.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/catalog/heap.c,v
retrieving revision 1.167
diff -c -r1.167 heap.c
*** src/backend/catalog/heap.c    2001/06/12 05:55:49    1.167
--- src/backend/catalog/heap.c    2001/06/14 16:33:51
***************
*** 281,288 ****
           * replace relname of caller with a unique name for a temp
           * relation
           */
!         snprintf(relname, NAMEDATALEN, "pg_temp.%d.%u",
!                  (int) MyProcPid, uniqueId++);
      }

      /*
--- 281,288 ----
           * replace relname of caller with a unique name for a temp
           * relation
           */
!         snprintf(relname, NAMEDATALEN, "%s_%d_%u",
!                 PG_TEMP_REL_PREFIX, (int) MyProcPid, uniqueId++);
      }

      /*
***************
*** 874,910 ****
  }


- /* ----------------------------------------------------------------
-  *        heap_drop_with_catalog    - removes all record of named relation from catalogs
-  *
-  *        1)    open relation, check for existence, etc.
-  *        2)    remove inheritance information
-  *        3)    remove indexes
-  *        4)    remove pg_class tuple
-  *        5)    remove pg_attribute tuples and related descriptions
-  *                6)        remove pg_description tuples
-  *        7)    remove pg_type tuples
-  *        8)    RemoveConstraints ()
-  *        9)    unlink relation
-  *
-  * old comments
-  *        Except for vital relations, removes relation from
-  *        relation catalog, and related attributes from
-  *        attribute catalog (needed?).  (Anything else?)
-  *
-  *        get proper relation from relation catalog (if not arg)
-  *        scan attribute catalog deleting attributes of reldesc
-  *                (necessary?)
-  *        delete relation from relation catalog
-  *        (How are the tuples of the relation discarded?)
-  *
-  *        XXX Must fix to work with indexes.
-  *        There may be a better order for doing things.
-  *        Problems with destroying a deleted database--cannot create
-  *        a struct reldesc without having an open file descriptor.
-  * ----------------------------------------------------------------
-  */
-
  /* --------------------------------
   *        RelationRemoveInheritance
   *
--- 874,879 ----
***************
*** 1334,1343 ****
      heap_close(pg_type_desc, RowExclusiveLock);
  }

! /* --------------------------------
!  *        heap_drop_with_catalog
   *
!  * --------------------------------
   */
  void
  heap_drop_with_catalog(const char *relname,
--- 1303,1337 ----
      heap_close(pg_type_desc, RowExclusiveLock);
  }

! /* ----------------------------------------------------------------
!  *        heap_drop_with_catalog    - removes all record of named relation from catalogs
   *
!  *        1)    open relation, check for existence, etc.
!  *        2)    remove inheritance information
!  *        3)    remove indexes
!  *        4)    remove pg_class tuple
!  *        5)    remove pg_attribute tuples and related descriptions
!  *                6)        remove pg_description tuples
!  *        7)    remove pg_type tuples
!  *        8)    RemoveConstraints ()
!  *        9)    unlink relation
!  *
!  * old comments
!  *        Except for vital relations, removes relation from
!  *        relation catalog, and related attributes from
!  *        attribute catalog (needed?).  (Anything else?)
!  *
!  *        get proper relation from relation catalog (if not arg)
!  *        scan attribute catalog deleting attributes of reldesc
!  *                (necessary?)
!  *        delete relation from relation catalog
!  *        (How are the tuples of the relation discarded?)
!  *
!  *        XXX Must fix to work with indexes.
!  *        There may be a better order for doing things.
!  *        Problems with destroying a deleted database--cannot create
!  *        a struct reldesc without having an open file descriptor.
!  * ----------------------------------------------------------------
   */
  void
  heap_drop_with_catalog(const char *relname,
***************
*** 1360,1367 ****
       * prevent deletion of system relations
       */
      /* allow temp of pg_class? Guess so. */
!     if (!istemp && !allow_system_table_mods &&
!         IsSystemRelationName(RelationGetRelationName(rel)))
          elog(ERROR, "System relation \"%s\" may not be dropped",
               RelationGetRelationName(rel));

--- 1354,1363 ----
       * prevent deletion of system relations
       */
      /* allow temp of pg_class? Guess so. */
!     if (!istemp &&
!         !allow_system_table_mods &&
!         IsSystemRelationName(RelationGetRelationName(rel)) &&
!         !is_temp_relname(RelationGetRelationName(rel)))
          elog(ERROR, "System relation \"%s\" may not be dropped",
               RelationGetRelationName(rel));

Index: src/backend/commands/vacuum.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/commands/vacuum.c,v
retrieving revision 1.196
diff -c -r1.196 vacuum.c
*** src/backend/commands/vacuum.c    2001/06/13 21:44:40    1.196
--- src/backend/commands/vacuum.c    2001/06/14 16:33:53
***************
*** 491,497 ****
      vacuum_pages.num_pages = fraged_pages.num_pages = 0;
      scan_heap(vacrelstats, onerel, &vacuum_pages, &fraged_pages);
      if (IsIgnoringSystemIndexes() &&
!         IsSystemRelationName(RelationGetRelationName(onerel)))
          reindex = true;

      /* Now open indices */
--- 491,498 ----
      vacuum_pages.num_pages = fraged_pages.num_pages = 0;
      scan_heap(vacrelstats, onerel, &vacuum_pages, &fraged_pages);
      if (IsIgnoringSystemIndexes() &&
!         IsSystemRelationName(RelationGetRelationName(onerel)) &&
!         !is_temp_relname(RelationGetRelationName(onerel)))
          reindex = true;

      /* Now open indices */
Index: src/backend/storage/file/fd.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/storage/file/fd.c,v
retrieving revision 1.81
diff -c -r1.81 fd.c
*** src/backend/storage/file/fd.c    2001/06/11 04:12:29    1.81
--- src/backend/storage/file/fd.c    2001/06/14 16:34:02
***************
*** 756,762 ****
       * transaction and database instance.
       */
      snprintf(tempfilepath, sizeof(tempfilepath),
!              "%s/%s%d.%ld", PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
               MyProcPid, tempFileCounter++);

      /*
--- 756,762 ----
       * transaction and database instance.
       */
      snprintf(tempfilepath, sizeof(tempfilepath),
!              "%s/%s%d_%ld", PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
               MyProcPid, tempFileCounter++);

      /*
Index: src/backend/tcop/utility.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/tcop/utility.c,v
retrieving revision 1.113
diff -c -r1.113 utility.c
*** src/backend/tcop/utility.c    2001/06/09 23:21:54    1.113
--- src/backend/tcop/utility.c    2001/06/14 16:34:02
***************
*** 46,51 ****
--- 46,52 ----
  #include "utils/acl.h"
  #include "utils/ps_status.h"
  #include "utils/syscache.h"
+ #include "utils/temprel.h"
  #include "access/xlog.h"

  /*
***************
*** 120,126 ****
          elog(ERROR, "you do not own %s \"%s\"",
               rentry->name, name);

!     if (!allowSystemTableMods && IsSystemRelationName(name))
          elog(ERROR, "%s \"%s\" is a system %s",
               rentry->name, name, rentry->name);

--- 121,128 ----
          elog(ERROR, "you do not own %s \"%s\"",
               rentry->name, name);

!     if (!allowSystemTableMods && IsSystemRelationName(name) &&
!         !is_temp_relname(name))
          elog(ERROR, "%s \"%s\" is a system %s",
               rentry->name, name, rentry->name);

Index: src/include/utils/temprel.h
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/include/utils/temprel.h,v
retrieving revision 1.15
diff -c -r1.15 temprel.h
*** src/include/utils/temprel.h    2001/03/22 04:01:14    1.15
--- src/include/utils/temprel.h    2001/06/14 16:34:03
***************
*** 16,21 ****
--- 16,26 ----

  #include "access/htup.h"

+ #define PG_TEMP_REL_PREFIX "pg_temp"
+
+ #define is_temp_relname(relname) \
+         (!strncmp(relname, PG_TEMP_REL_PREFIX, strlen(PG_TEMP_REL_PREFIX)))
+
  extern void create_temp_relation(const char *relname,
                       HeapTuple pg_class_tuple);
  extern void remove_temp_rel_by_relid(Oid relid);