diff options
| author | Peter Geoghegan | 2025-07-16 17:05:44 +0000 |
|---|---|---|
| committer | Peter Geoghegan | 2025-07-16 17:05:44 +0000 |
| commit | 4c8ad67a98b5d84c1ca00a26d53d08f2d2b881aa (patch) | |
| tree | 2b58a3eef80132b9611ca1cfd205b84bdce4595a /src | |
| parent | 48c2c7b4b45b3bb696d566f4f425fccdd871532f (diff) | |
nbtree: Use only one notnullkey ScanKeyData.
_bt_first need only store one ScanKeyData struct on the stack for the
purposes of building an IS NOT NULL key based on an implied NOT NULL
constraint. We don't need INDEX_MAX_KEYS-many ScanKeyData structs.
This saves us a little over 2KB in stack space. It's possible that this
has some performance benefit. It also seems simpler and more direct.
It isn't possible for more than a single index attribute to need its own
implied IS NOT NULL key: the first such attribute/IS NOT NULL key always
makes _bt_first stop adding additional boundary keys to startKeys[].
Using INDEX_MAX_KEYS-many ScanKeyData entries was (at best) misleading.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Mircea Cadariu <cadariu.mircea@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wzm=1kJMSZhhTLoM5BPbwQNWxUj-ynOEh=89ptDZAVgauw@mail.gmail.com
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtsearch.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c index 4af1ff1e9e5..d69798795b4 100644 --- a/src/backend/access/nbtree/nbtsearch.c +++ b/src/backend/access/nbtree/nbtsearch.c @@ -892,9 +892,9 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) OffsetNumber offnum; BTScanInsertData inskey; ScanKey startKeys[INDEX_MAX_KEYS]; - ScanKeyData notnullkeys[INDEX_MAX_KEYS]; + ScanKeyData notnullkey; int keysz = 0; - StrategyNumber strat_total; + StrategyNumber strat_total = InvalidStrategy; BlockNumber blkno = InvalidBlockNumber, lastcurrblkno; @@ -1034,7 +1034,6 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) * need to be kept in sync. *---------- */ - strat_total = BTEqualStrategyNumber; if (so->numberOfKeys > 0) { AttrNumber curattr; @@ -1122,16 +1121,15 @@ _bt_first(IndexScanDesc scan, ScanDirection dir) ScanDirectionIsForward(dir) : ScanDirectionIsBackward(dir))) { - /* Yes, so build the key in notnullkeys[keysz] */ - bkey = ¬nullkeys[keysz]; + /* Final startKeys[] entry will be deduced NOT NULL key */ + bkey = ¬nullkey; ScanKeyEntryInitialize(bkey, (SK_SEARCHNOTNULL | SK_ISNULL | (impliesNN->sk_flags & (SK_BT_DESC | SK_BT_NULLS_FIRST))), curattr, - ((impliesNN->sk_flags & SK_BT_NULLS_FIRST) ? - BTGreaterStrategyNumber : - BTLessStrategyNumber), + ScanDirectionIsForward(dir) ? + BTGreaterStrategyNumber : BTLessStrategyNumber, InvalidOid, InvalidOid, InvalidOid, |