Op 20-04-2022 om 06:54 schreef Kyotaro Horiguchi:
At Tue, 19 Apr 2022 10:55:26 -0700, Andres Freund <and...@anarazel.de> wrote in
Hi,
On 2022-04-19 10:36:24 -0700, Andres Freund wrote:
On 2022-04-19 13:50:25 +0200, Erik Rijkers wrote:
The 12th run of statbug.sh crashed and gave a corefile.
I ran through quite a few iterations by now, without reproducing :(
I guess there's some timing issue and you're hitting on your system
due to the slower disks.
Ah. I found the issue. The new pgstat_report_stat(true) call in
LogicalRepApplyLoop()'s "timeout" section doesn't check if we're in a
transaction. And the transactional stats code doesn't handle that (never
has).
I think all that's needed is a if (IsTransactionState()) around that
pgstat_report_stat().
if (!IsTransactinoState()) ?
It might be possible to put an assertion into pgstat_report_stat(), but
I need to look at the process exit code to see if it is.
Inserting a sleep in pgoutput_commit_txn reproduced this. Crashes with
the same stack trace with the similar variable state.
diff --git a/src/backend/replication/pgoutput/pgoutput.c
b/src/backend/replication/pgoutput/pgoutput.c
index b197bfd565..def4d751d3 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -568,6 +568,7 @@ pgoutput_commit_txn(LogicalDecodingContext *ctx,
ReorderBufferTXN *txn,
return;
}
+ sleep(2);
OutputPluginPrepareWrite(ctx, true);
logicalrep_write_commit(ctx->out, txn, commit_lsn);
OutputPluginWrite(ctx, true);
The following actuall works for this.
diff --git a/src/backend/replication/logical/worker.c
b/src/backend/replication/logical/worker.c
index 4171371296..f4e5359513 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -2882,10 +2882,11 @@ LogicalRepApplyLoop(XLogRecPtr last_received)
send_feedback(last_received, requestReply,
requestReply);
/*
- * Force reporting to ensure long idle periods don't
lead to
- * arbitrarily delayed stats.
+ * Force reporting to ensure long out-of-transaction
idle periods
+ * don't lead to arbitrarily delayed stats.
*/
- pgstat_report_stat(true);
+ if (!IsTransactionState())
+ pgstat_report_stat(true);
}
}
Yes, that seems to fix it: I applied that latter patch, and ran my
program 250x without errors. Then I removed it again an it gave the
error within 15x.
thanks!
Erik
regards.
