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author | Tom Lane | 2011-10-08 00:13:02 +0000 |
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committer | Tom Lane | 2011-10-08 00:14:13 +0000 |
commit | a2822fb9337a21f98ac4ce850bb4145acf47ca27 (patch) | |
tree | c239fe9a32ff0225e906711a76348cee1567f0d8 /src/backend/access/gist/gistproc.c | |
parent | caa1054df8408b165e5f66ff25c87b6dd0a0a1e7 (diff) |
Support index-only scans using the visibility map to avoid heap fetches.
When a btree index contains all columns required by the query, and the
visibility map shows that all tuples on a target heap page are
visible-to-all, we don't need to fetch that heap page. This patch depends
on the previous patches that made the visibility map reliable.
There's a fair amount left to do here, notably trying to figure out a less
chintzy way of estimating the cost of an index-only scan, but the core
functionality seems ready to commit.
Robert Haas and Ibrar Ahmed, with some previous work by Heikki Linnakangas.
Diffstat (limited to 'src/backend/access/gist/gistproc.c')
0 files changed, 0 insertions, 0 deletions