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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-08-31 16:23:20 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-08-31 16:23:20 -0400 |
| commit | 0c599e748f2c81e415bb39567c4fd40a6bc64815 (patch) | |
| tree | efcf2db2aaaf9676e5bf7d3a476b32300d459c6a /src | |
| parent | 61f6e5c2360382be99846be904af33e3406c938a (diff) | |
| download | postgresql-0c599e748f2c81e415bb39567c4fd40a6bc64815.tar.gz postgresql-0c599e748f2c81e415bb39567c4fd40a6bc64815.zip | |
Prevent long-term memory leakage in autovacuum launcher.
get_database_list() failed to restore the caller's memory context,
instead leaving current context set to TopMemoryContext which is
how CommitTransactionCommand() leaves it. The callers both think
they are using short-lived contexts, for the express purpose of
not having to worry about cleaning up individual allocations.
The net effect therefore is that supposedly short-lived allocations
could accumulate indefinitely in the launcher's TopMemoryContext.
Although this has been broken for a long time, it seems we didn't
have any obvious memory leak here until v15's rearrangement of the
stats logic. I (tgl) am not entirely convinced that there's no
other leak at all, though, and we're surely at risk of adding one
in future back-patched fixes. So back-patch to all supported
branches, even though this may be only a latent bug in pre-v15.
Reid Thompson
Discussion: https://postgr.es/m/972a4e12b68b0f96db514777a150ceef7dcd2e0f.camel@crunchydata.com
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/postmaster/autovacuum.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 70a9176c54c..171122d394b 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -1941,6 +1941,9 @@ get_database_list(void) CommitTransactionCommand(); + /* Be sure to restore caller's memory context */ + MemoryContextSwitchTo(resultcxt); + return dblist; } |