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| author | Peter Geoghegan <pg@bowt.ie> | 2021-03-16 13:38:52 -0700 |
|---|---|---|
| committer | Peter Geoghegan <pg@bowt.ie> | 2021-03-16 13:38:52 -0700 |
| commit | fbe4cb3bd49f9e524f53ef77c775c1bad4d0312a (patch) | |
| tree | e973ffb6f952ec2dcc4c446d1f62efb2378fba25 | |
| parent | 65445469d6de3670f3e027236613e093e119ec55 (diff) | |
| download | postgresql-fbe4cb3bd49f9e524f53ef77c775c1bad4d0312a.tar.gz postgresql-fbe4cb3bd49f9e524f53ef77c775c1bad4d0312a.zip | |
Fix comment about promising tuples.
Oversight in commit d168b666823, which added bottom-up index deletion.
| -rw-r--r-- | src/backend/access/heap/heapam.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 3b435c107d0..7cb87f4a3b3 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -7879,8 +7879,10 @@ bottomup_sort_and_shrink(TM_IndexDeleteOp *delstate) /* * We're about ready to sort block groups to determine the optimal order * for visiting heap blocks. But before we do, round the number of - * promising tuples for each block group up to the nearest power-of-two - * (except for block groups where npromisingtids is already 0). + * promising tuples for each block group up to the next power-of-two, + * unless it is very low (less than 4), in which case we round up to 4. + * npromisingtids is far too noisy to trust when choosing between a pair + * of block groups that both have very low values. * * This scheme divides heap blocks/block groups into buckets. Each bucket * contains blocks that have _approximately_ the same number of promising |