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| author | Peter Geoghegan <pg@bowt.ie> | 2020-03-30 12:03:57 -0700 |
|---|---|---|
| committer | Peter Geoghegan <pg@bowt.ie> | 2020-03-30 12:03:57 -0700 |
| commit | 97cda93d81dc89ab05703e1c3344525ab268e49f (patch) | |
| tree | 8ef429223ed3b9c0cc09bf3eb623137ba31287e8 /src/backend/access/nbtree/nbtutils.c | |
| parent | de5b9db3644d5262940c72bab174b43f0bc696cd (diff) | |
| download | postgresql-97cda93d81dc89ab05703e1c3344525ab268e49f.tar.gz postgresql-97cda93d81dc89ab05703e1c3344525ab268e49f.zip | |
Consistently truncate non-key suffix columns.
INCLUDE indexes failed to have their non-key attributes physically
truncated away in certain rare cases. This led to physically larger
pivot tuples that contained useless non-key attribute values. The
impact on users should be negligible, but this is still clearly a
regression (Postgres 11 supports INCLUDE indexes, and yet was not
affected).
The bug appeared in commit dd299df8, which introduced "true" suffix
truncation of key attributes.
Discussion: https://postgr.es/m/CAH2-Wz=E8pkV9ivRSFHtv812H5ckf8s1-yhx61_WrJbKccGcrQ@mail.gmail.com
Backpatch: 12-, where "true" suffix truncation was introduced.
Diffstat (limited to 'src/backend/access/nbtree/nbtutils.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtutils.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c index 93fab264ae4..a1e7636adb1 100644 --- a/src/backend/access/nbtree/nbtutils.c +++ b/src/backend/access/nbtree/nbtutils.c @@ -2143,7 +2143,8 @@ _bt_truncate(Relation rel, IndexTuple lastleft, IndexTuple firstright, { IndexTuple tidpivot; - pivot = index_truncate_tuple(itupdesc, firstright, keepnatts); + pivot = index_truncate_tuple(itupdesc, firstright, + Min(keepnatts, nkeyatts)); /* * If there is a distinguishing key attribute within new pivot tuple, @@ -2173,6 +2174,10 @@ _bt_truncate(Relation rel, IndexTuple lastleft, IndexTuple firstright, /* * No truncation was possible, since key attributes are all equal. * It's necessary to add a heap TID attribute to the new pivot tuple. + * + * This path is only taken when rel is not an INCLUDE index. It + * avoids a second palloc0() by avoiding the index_truncate_tuple() + * call completely. */ Assert(natts == nkeyatts); newsize = IndexTupleSize(firstright) + MAXALIGN(sizeof(ItemPointerData)); |