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| author | Peter Eisentraut <peter_e@gmx.net> | 2018-08-23 15:13:48 +0200 |
|---|---|---|
| committer | Peter Eisentraut <peter_e@gmx.net> | 2018-08-27 22:15:39 +0200 |
| commit | 2657d4ea66c775c3334181722115be2d6128c5cd (patch) | |
| tree | d42cae822e260a54c487527db13c8cc131840889 /src/backend/utils | |
| parent | c5e235ff8ad0f4907a736a6440dc4be6f939e65c (diff) | |
| download | postgresql-2657d4ea66c775c3334181722115be2d6128c5cd.tar.gz postgresql-2657d4ea66c775c3334181722115be2d6128c5cd.zip | |
Fix snapshot leak warning for some procedures
The problem arises with the combination of CALL with output parameters
and doing a COMMIT inside the procedure. When a CALL has output
parameters, the portal uses the strategy PORTAL_UTIL_SELECT instead of
PORTAL_MULTI_QUERY. Using PORTAL_UTIL_SELECT causes the portal's
snapshot to be registered with the current resource
owner (portal->holdSnapshot); see
9ee1cf04ab6bcefe03a11837b53f29ca9dc24c7a for the reason.
Normally, PortalDrop() unregisters the snapshot. If not, then
ResourceOwnerRelease() will print a warning about a snapshot leak on
transaction commit. A transaction commit normally drops all
portals (PreCommit_Portals()), except the active portal. So in case of
the active portal, we need to manually release the snapshot to avoid the
warning.
Reported-by: Prabhat Sahu <prabhat.sahu@enterprisedb.com>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Diffstat (limited to 'src/backend/utils')
| -rw-r--r-- | src/backend/utils/mmgr/portalmem.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c index 04ea32f49f2..d34cab0eb88 100644 --- a/src/backend/utils/mmgr/portalmem.c +++ b/src/backend/utils/mmgr/portalmem.c @@ -689,13 +689,23 @@ PreCommit_Portals(bool isPrepare) /* * Do not touch active portals --- this can only happen in the case of - * a multi-transaction utility command, such as VACUUM. + * a multi-transaction utility command, such as VACUUM, or a commit in + * a procedure. * * Note however that any resource owner attached to such a portal is - * still going to go away, so don't leave a dangling pointer. + * still going to go away, so don't leave a dangling pointer. Also + * unregister any snapshots held by the portal, mainly to avoid + * snapshot leak warnings from ResourceOwnerRelease(). */ if (portal->status == PORTAL_ACTIVE) { + if (portal->holdSnapshot) + { + if (portal->resowner) + UnregisterSnapshotFromOwner(portal->holdSnapshot, + portal->resowner); + portal->holdSnapshot = NULL; + } portal->resowner = NULL; continue; } |