diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/indexam.sgml | 5 | ||||
| -rw-r--r-- | doc/src/sgml/indices.sgml | 16 |
2 files changed, 10 insertions, 11 deletions
diff --git a/doc/src/sgml/indexam.sgml b/doc/src/sgml/indexam.sgml index 61956cdfcf5..70fba4ecc0a 100644 --- a/doc/src/sgml/indexam.sgml +++ b/doc/src/sgml/indexam.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.11 2006/05/10 23:18:38 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/indexam.sgml,v 2.12 2006/05/24 11:01:39 teodor Exp $ --> <chapter id="indexam"> <title>Index Access Method Interface Definition</title> @@ -126,8 +126,7 @@ used to scan for rows with <literal>a = 4</literal>, which is wrong if the index omits rows where <literal>b</> is null. It is, however, OK to omit rows where the first indexed column is null. - (GiST currently does so.) Thus, - <structfield>amindexnulls</structfield> should be set true only if the + Thus, <structfield>amindexnulls</structfield> should be set true only if the index access method indexes all rows, including arbitrary combinations of null values. </para> diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml index 9bb19c2cee0..10669c01557 100644 --- a/doc/src/sgml/indices.sgml +++ b/doc/src/sgml/indices.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.56 2006/01/18 21:29:45 momjian Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.57 2006/05/24 11:01:39 teodor Exp $ --> <chapter id="indexes"> <title id="indexes-title">Indexes</title> @@ -290,13 +290,13 @@ CREATE INDEX test2_mm_idx ON test2 (major, minor); </para> <para> - A multicolumn GiST index can only be used when there is a query condition - on its leading column. Conditions on additional columns restrict the - entries returned by the index, but the condition on the first column is the - most important one for determining how much of the index needs to be - scanned. A GiST index will be relatively ineffective if its first column - has only a few distinct values, even if there are many distinct values in - additional columns. + A multicolumn GiST index can be used with query conditions that + involve any subset of the index's columns. Conditions on additional + columns restrict the entries returned by the index, but the condition on + the first column is the most important one for determining how much of + the index needs to be scanned. A GiST index will be relatively + ineffective if its first column has only a few distinct values, even if + there are many distinct values in additional columns. </para> <para> |