diff options
author | Tom Lane <tgl@sss.pgh.pa.us> | 2019-06-03 18:06:04 -0400 |
---|---|---|
committer | Tom Lane <tgl@sss.pgh.pa.us> | 2019-06-03 18:06:04 -0400 |
commit | 2cd4e835701e15f5e32dd8bde488f8669ddf7ae8 (patch) | |
tree | 23b7f54b6935416d4dcfae8ec3d8e8f9fa1e205e /src/backend/executor/nodeFunctionscan.c | |
parent | eaf0292c3ba7acac2735f99a8988bd49a26112f5 (diff) | |
download | postgresql-2cd4e835701e15f5e32dd8bde488f8669ddf7ae8.tar.gz postgresql-2cd4e835701e15f5e32dd8bde488f8669ddf7ae8.zip |
Fix contrib/auto_explain to not cause problems in parallel workers.
A parallel worker process should not be making any decisions of its
own about whether to auto-explain. If the parent session process
passed down flags asking for instrumentation data, do that, otherwise
not. Trying to enable instrumentation anyway leads to bugs like the
"could not find key N in shm TOC" failure reported in bug #15821
from Christian Hofstaedtler.
We can implement this cheaply by piggybacking on the existing logic
for not doing anything when we've chosen not to sample a statement.
While at it, clean up some tin-eared coding related to the sampling
feature, including an off-by-one error that meant that asking for 1.0
sampling rate didn't actually result in sampling every statement.
Although the specific case reported here only manifested in >= v11,
I believe that related misbehaviors can be demonstrated in any version
that has parallel query; and the off-by-one error is certainly there
back to 9.6 where that feature was added. So back-patch to 9.6.
Discussion: https://postgr.es/m/15821-5eb422e980594075@postgresql.org
Diffstat (limited to 'src/backend/executor/nodeFunctionscan.c')
0 files changed, 0 insertions, 0 deletions