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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2014-11-28 13:37:25 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2014-11-28 13:37:25 -0500 |
| commit | f4e031c662a6b600b786c4849968a099c58fcce7 (patch) | |
| tree | 6a082f889ff2ea5b64bb43c467760686e5f013b0 /src/include/nodes/bitmapset.h | |
| parent | 96d66bcfc60d9bcb7db767f23d33abf4d8bc7021 (diff) | |
| download | postgresql-f4e031c662a6b600b786c4849968a099c58fcce7.tar.gz | |
Add bms_next_member(), and use it where appropriate.
This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member(). While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.
Tom Lane, with suggestions from Dean Rasheed and David Rowley
Diffstat (limited to 'src/include/nodes/bitmapset.h')
| -rw-r--r-- | src/include/nodes/bitmapset.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/include/nodes/bitmapset.h b/src/include/nodes/bitmapset.h index f77060844f..a78ff4886d 100644 --- a/src/include/nodes/bitmapset.h +++ b/src/include/nodes/bitmapset.h @@ -89,6 +89,7 @@ extern Bitmapset *bms_join(Bitmapset *a, Bitmapset *b); /* support for iterating through the integer elements of a set: */ extern int bms_first_member(Bitmapset *a); +extern int bms_next_member(const Bitmapset *a, int prevbit); /* support for hashtables using Bitmapsets as keys: */ extern uint32 bms_hash_value(const Bitmapset *a); |