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| -rw-r--r-- | doc/src/sgml/pgstattuple.sgml | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/doc/src/sgml/pgstattuple.sgml b/doc/src/sgml/pgstattuple.sgml index 9ada5d209af..d2fa524d6ec 100644 --- a/doc/src/sgml/pgstattuple.sgml +++ b/doc/src/sgml/pgstattuple.sgml @@ -117,6 +117,16 @@ free_percent | 1.95 </tgroup> </table> + <note> + <para> + The <literal>table_len</literal> will always be greater than the sum + of the <literal>tuple_len</literal>, <literal>dead_tuple_len</literal> + and <literal>free_space</literal>. The difference is accounted for by + fixed page overhead, the per-page table of pointers to tuples, and + padding to ensure that tuples are correctly aligned. + </para> + </note> + <para> <function>pgstattuple</function> acquires only a read lock on the relation. So the results do not reflect an instantaneous snapshot; |