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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2018-03-01 15:35:03 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2018-03-01 15:35:03 -0500 |
| commit | b5febc1d125cac37c626cb7c96936db6839ec733 (patch) | |
| tree | aa4942ed2735a585b5bbb0538e13ac6e37acfc17 /contrib/btree_gist/sql | |
| parent | 6452b098c018a8aa9fbcf28d6be22d92493301fd (diff) | |
| download | postgresql-b5febc1d125cac37c626cb7c96936db6839ec733.tar.gz postgresql-b5febc1d125cac37c626cb7c96936db6839ec733.zip | |
Fix IOS planning when only some index columns can return an attribute.
Since 9.5, it's possible that some but not all columns of an index
support returning the indexed value for index-only scans. If the
same indexed column appears in index columns that behave both ways,
check_index_only() supposed that it'd be OK to do an index-only scan
testing that column; but that fails if we have to recheck the indexed
condition on one of the columns that doesn't support this.
In principle we could make this work by remapping the recheck expressions
to pull the value from a column that does support returning the indexed
value. But such cases are so weird and rare that, at least for now,
it doesn't seem worth the trouble. Instead, just teach check_index_only
that a value is returnable only if all the index columns containing it
are returnable, rather than any of them.
Per report from David Pereiro Lagares. Back-patch to 9.5 where the
possibility of this situation appeared.
Kyotaro Horiguchi
Discussion: https://postgr.es/m/1516210494.1798.16.camel@nlpgo.com
Diffstat (limited to 'contrib/btree_gist/sql')
| -rw-r--r-- | contrib/btree_gist/sql/inet.sql | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/contrib/btree_gist/sql/inet.sql b/contrib/btree_gist/sql/inet.sql index 328846c0a38..08952f2c449 100644 --- a/contrib/btree_gist/sql/inet.sql +++ b/contrib/btree_gist/sql/inet.sql @@ -29,3 +29,21 @@ SELECT count(*) FROM inettmp WHERE a = '89.225.196.191'::inet; SELECT count(*) FROM inettmp WHERE a >= '89.225.196.191'::inet; SELECT count(*) FROM inettmp WHERE a > '89.225.196.191'::inet; + +VACUUM inettmp; + +-- gist_inet_ops lacks a fetch function, so this should not be index-only scan +EXPLAIN (COSTS OFF) +SELECT count(*) FROM inettmp WHERE a = '89.225.196.191'::inet; + +SELECT count(*) FROM inettmp WHERE a = '89.225.196.191'::inet; + +DROP INDEX inetidx; + +CREATE INDEX ON inettmp USING gist (a gist_inet_ops, a inet_ops); + +-- likewise here (checks for core planner bug) +EXPLAIN (COSTS OFF) +SELECT count(*) FROM inettmp WHERE a = '89.225.196.191'::inet; + +SELECT count(*) FROM inettmp WHERE a = '89.225.196.191'::inet; |