Re: Sync Rep for 2011CF1 - Mailing list pgsql-hackers

From Jaime Casanova
Subject Re: Sync Rep for 2011CF1
Date
Msg-id AANLkTikFzAgjpiM6KsfGt-u4j8SE5C76-d+BFhzkAXd2@mail.gmail.com
Whole thread Raw
In response to Sync Rep for 2011CF1  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Sync Rep for 2011CF1  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
On Sat, Jan 15, 2011 at 4:40 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
>
> Here's the latest patch for sync rep.
>

I was looking at this code and found something in SyncRepWaitOnQueue
we declare a timeout variable that is a long and another that is a
boolean (this last one in the else part of the "if
(!IsOnSyncRepQueue())"), and then use the boolean one as if it were
the long one

+       else
+       {
+           bool release = false;
+           bool timeout = false;
+
+           SpinLockAcquire(&queue->qlock);
+
+           /*
+            * Check the LSN on our queue and if its moved far enough then
+            * remove us from the queue. First time through this is
+            * unlikely to be far enough, yet is possible. Next time we are
+            * woken we should be more lucky.
+            */
+           if (XLByteLE(XactCommitLSN, queue->lsn))
+               release = true;
+           else if (timeout > 0 &&
+               TimestampDifferenceExceeds(GetCurrentTransactionStopTimestamp(),
+                                       now,
+                                       timeout))
+           {
+               release = true;
+               timeout = true;
+           }

the other two things are on postgresql.conf.sample:
- we have two replication_timeout_client, obviously one of them should
be replication_timeout_server
- synchronous_replication_feedback is off by default, but docs says otherwise

i also have been testing this, until now the only issue i have found
is that if i set allow_standalone_primary to off and there isn't a
standby connected i need to stop the server with -m immediate which is
at least surprising

--
Jaime Casanova         www.2ndQuadrant.com
Professional PostgreSQL: Soporte y capacitación de PostgreSQL


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