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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-07 20:13:02 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-10-07 20:14:13 -0400 |
| commit | a2822fb9337a21f98ac4ce850bb4145acf47ca27 (patch) | |
| tree | c239fe9a32ff0225e906711a76348cee1567f0d8 /src/backend/tcop/postgres.c | |
| parent | caa1054df8408b165e5f66ff25c87b6dd0a0a1e7 (diff) | |
| download | postgresql-a2822fb9337a21f98ac4ce850bb4145acf47ca27.tar.gz postgresql-a2822fb9337a21f98ac4ce850bb4145acf47ca27.zip | |
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/tcop/postgres.c')
| -rw-r--r-- | src/backend/tcop/postgres.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c index 19d94b252c2..976a832135e 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -3065,7 +3065,7 @@ set_debug_options(int debug_flag, GucContext context, GucSource source) bool set_plan_disabling_options(const char *arg, GucContext context, GucSource source) { - char *tmp = NULL; + const char *tmp = NULL; switch (arg[0]) { @@ -3075,6 +3075,9 @@ set_plan_disabling_options(const char *arg, GucContext context, GucSource source case 'i': /* indexscan */ tmp = "enable_indexscan"; break; + case 'o': /* indexonlyscan */ + tmp = "enable_indexonlyscan"; + break; case 'b': /* bitmapscan */ tmp = "enable_bitmapscan"; break; |