diff options
| -rw-r--r-- | doc/src/sgml/indexam.sgml | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/doc/src/sgml/indexam.sgml b/doc/src/sgml/indexam.sgml index 4f83970c851..1a787179a34 100644 --- a/doc/src/sgml/indexam.sgml +++ b/doc/src/sgml/indexam.sgml @@ -319,9 +319,13 @@ aminsert (Relation indexRelation, modify any columns covered by the index, but nevertheless requires a new version in the index. The index AM may use this hint to decide to apply bottom-up index deletion in parts of the index where many - versions of the same logical row accumulate. Note that updating a - non-key column does not affect the value of - <literal>indexUnchanged</literal>. + versions of the same logical row accumulate. Note that updating a non-key + column or a column that only appears in a partial index predicate does not + affect the value of <literal>indexUnchanged</literal>. The core code + determines each tuple's <literal>indexUnchanged</literal> value using a low + overhead approach that allows both false positives and false negatives. + Index AMs must not treat <literal>indexUnchanged</literal> as an + authoritative source of information about tuple visibility or versioning. </para> <para> |