diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/datatype.sgml | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 49fb19ff919..7027758d28d 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -4801,7 +4801,13 @@ SELECT * FROM pg_attribute standard comparison operators, like <literal>=</literal> and <literal>></literal>. Two LSNs can be subtracted using the <literal>-</literal> operator; the result is the number of bytes separating - those write-ahead log locations. + those write-ahead log locations. Also the number of bytes can be + added into and subtracted from LSN using the + <literal>+(pg_lsn,numeric)</literal> and + <literal>-(pg_lsn,numeric)</literal> operators, respectively. Note that + the calculated LSN should be in the range of <type>pg_lsn</type> type, + i.e., between <literal>0/0</literal> and + <literal>FFFFFFFF/FFFFFFFF</literal>. </para> </sect1> |