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commit    8f22fe2025bf97bc2bd6e0a7b3acf97ab970a4e2
Author:   Bruce Momjian <bruce@momjian.us>
Date:     Wed Dec 22 21:29:16 2021 +0000
First released in: 15.0, 10.20, 11.15, 12.10, 13.6, 14.2

    doc:  clarify when expression indexes evaluate their expressions
    
    Only non-HOT updates evaluate the index expression.
    
    Reported-by: Chris Lowder
    
    Discussion: https://postgr.es/m/163967385701.26064.15365003480975321072@wrigleys.postgresql.org
    
    Backpatch-through: 10


 doc/src/sgml/indices.sgml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml
index 3d5325de916..8a9beae7b43 100644
--- a/doc/src/sgml/indices.sgml
+++ b/doc/src/sgml/indices.sgml
@@ -725,8 +725,8 @@ CREATE INDEX people_names ON people ((first_name || ' ' || last_name));
 
   <para>
    Index expressions are relatively expensive to maintain, because the
-   derived expression(s) must be computed for each row upon insertion
-   and whenever it is updated.  However, the index expressions are
+   derived expression(s) must be computed for each row insertion
+   and non-HOT update.  However, the index expressions are
    <emphasis>not</> recomputed during an indexed search, since they are
    already stored in the index.  In both examples above, the system
    sees the query as just <literal>WHERE indexedcolumn = 'constant'</>


[parent: 9edca4cb57d2]