diff options
| -rw-r--r-- | doc/src/sgml/mvcc.sgml | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml index 020bbcd0e2a..49db3f176fa 100644 --- a/doc/src/sgml/mvcc.sgml +++ b/doc/src/sgml/mvcc.sgml @@ -692,6 +692,8 @@ SELECT SUM(value) FROM mytab WHERE class = 2; <literal>SHARE</literal>, <literal>SHARE ROW EXCLUSIVE</literal>, <literal>EXCLUSIVE</literal>, and <literal>ACCESS EXCLUSIVE</literal> lock modes. + This mode protects a table against concurrent data changes, and + is self-exclusive so that only one session can hold it at a time. </para> <para> @@ -719,9 +721,8 @@ SELECT SUM(value) FROM mytab WHERE class = 2; </para> <para> - This lock mode is not automatically acquired on user tables by any - <productname>PostgreSQL</productname> command. However it is - acquired on certain system catalogs in some operations. + This lock mode is not automatically acquired on tables by any + <productname>PostgreSQL</productname> command. </para> </listitem> </varlistentry> |