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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 16:23:35 -0400 |
| commit | 1c1294be716d96e804aadafc249fcbfa8367621d (patch) | |
| tree | 2b07aeb011e728d7dfc5969dc0f60507bb596253 /src | |
| parent | c3ffa731a5f99c4361203015ce2219d209fea94c (diff) | |
| download | postgresql-1c1294be716d96e804aadafc249fcbfa8367621d.tar.gz postgresql-1c1294be716d96e804aadafc249fcbfa8367621d.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 b3b1afba861..9dc6bf9477f 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; } |