diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtpreprocesskeys.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtpreprocesskeys.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/src/backend/access/nbtree/nbtpreprocesskeys.c b/src/backend/access/nbtree/nbtpreprocesskeys.c index 36813a96fff..21c519cd108 100644 --- a/src/backend/access/nbtree/nbtpreprocesskeys.c +++ b/src/backend/access/nbtree/nbtpreprocesskeys.c @@ -752,9 +752,12 @@ _bt_fix_scankey_strategy(ScanKey skey, int16 *indoption) * * Depending on the operator type, the key may be required for both scan * directions or just one. Also, if the key is a row comparison header, - * we have to mark its first subsidiary ScanKey as required. (Subsequent - * subsidiary ScanKeys are normally for lower-order columns, and thus - * cannot be required, since they're after the first non-equality scankey.) + * we have to mark the appropriate subsidiary ScanKeys as required. In such + * cases, the first subsidiary key is required, but subsequent ones are + * required only as long as they correspond to successive index columns and + * match the leading column as to sort direction. Otherwise the row + * comparison ordering is different from the index ordering and so we can't + * stop the scan on the basis of those lower-order columns. * * Note: when we set required-key flag bits in a subsidiary scankey, we are * scribbling on a data structure belonging to the index AM's caller, not on @@ -792,12 +795,25 @@ _bt_mark_scankey_required(ScanKey skey) if (skey->sk_flags & SK_ROW_HEADER) { ScanKey subkey = (ScanKey) DatumGetPointer(skey->sk_argument); + AttrNumber attno = skey->sk_attno; /* First subkey should be same column/operator as the header */ - Assert(subkey->sk_flags & SK_ROW_MEMBER); - Assert(subkey->sk_attno == skey->sk_attno); + Assert(subkey->sk_attno == attno); Assert(subkey->sk_strategy == skey->sk_strategy); - subkey->sk_flags |= addflags; + + for (;;) + { + Assert(subkey->sk_flags & SK_ROW_MEMBER); + if (subkey->sk_attno != attno) + break; /* non-adjacent key, so not required */ + if (subkey->sk_strategy != skey->sk_strategy) + break; /* wrong direction, so not required */ + subkey->sk_flags |= addflags; + if (subkey->sk_flags & SK_ROW_END) + break; + subkey++; + attno++; + } } } |