diff options
Diffstat (limited to 'doc/src/sgml/ref/create_statistics.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_statistics.sgml | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/doc/src/sgml/ref/create_statistics.sgml b/doc/src/sgml/ref/create_statistics.sgml index f319a6ea9c2..deda21fec7f 100644 --- a/doc/src/sgml/ref/create_statistics.sgml +++ b/doc/src/sgml/ref/create_statistics.sgml @@ -152,14 +152,14 @@ CREATE STATISTICS s1 (dependencies) ON a, b FROM t1; ANALYZE t1; --- now the rowcount estimate is more accurate: +-- now the row count estimate is more accurate: EXPLAIN ANALYZE SELECT * FROM t1 WHERE (a = 1) AND (b = 0); </programlisting> Without functional-dependency statistics, the planner would assume that the two <literal>WHERE</> conditions are independent, and would multiply their selectivities together to arrive at a much-too-small - rowcount estimate. + row count estimate. With such statistics, the planner recognizes that the <literal>WHERE</> conditions are redundant and does not underestimate the rowcount. </para> |