diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2020-09-01 18:37:12 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2020-09-01 18:40:43 -0400 |
| commit | a7212be8b9e0885ee769e8c55f99ef742cda487b (patch) | |
| tree | a0cb039b58cd2557725f63a2e60daf5392df3ffe /src/backend/access/heap/vacuumlazy.c | |
| parent | db864c3c36035e4620afd114c783af7d777d78b0 (diff) | |
Set cutoff xmin more aggressively when vacuuming a temporary table.
Since other sessions aren't allowed to look into a temporary table
of our own session, we do not need to worry about the global xmin
horizon when setting the vacuum XID cutoff. Indeed, if we're not
inside a transaction block, we may set oldestXmin to be the next
XID, because there cannot be any in-doubt tuples in a temp table,
nor any tuples that are dead but still visible to some snapshot of
our transaction. (VACUUM, of course, is never inside a transaction
block; but we need to test that because CLUSTER shares the same code.)
This approach allows us to always clean out a temp table completely
during VACUUM, independently of concurrent activity. Aside from
being useful in its own right, that simplifies building reproducible
test cases.
Discussion: https://postgr.es/m/3490536.1598629609@sss.pgh.pa.us
Diffstat (limited to 'src/backend/access/heap/vacuumlazy.c')
| -rw-r--r-- | src/backend/access/heap/vacuumlazy.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 53b1a952543..92389e6666b 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -471,6 +471,7 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params, params->freeze_table_age, params->multixact_freeze_min_age, params->multixact_freeze_table_age, + true, /* we must be a top-level command */ &OldestXmin, &FreezeLimit, &xidFullScanLimit, &MultiXactCutoff, &mxactFullScanLimit); |