On Sat, Nov 8, 2014 at 09:53:18PM +0100, Álvaro Hernández Tortosa wrote: > > On 07/11/14 22:02, Greg Sabino Mullane wrote: > >Kevin Grittner wrote: > >>>I think most people have always assumed that > >>>BEGIN starts the transaction and that is the point at > >>>which the snapshot is obtained. > >>But there is so much evidence to the contrary. Not only does the > >>*name* of the command (BEGIN or START) imply a start, but > >>pg_stat_activity shows the connection "idle in transaction" after > >>the command (and before a snapshot is acquired) > >Er...I think we are arguing the same thing here. So no contrary > >needed? :) > > So do we agree to fix the docs? ^_^
Doc patch attached. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. +
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml new file mode 100644 index a0d6867..e43a3be *** a/doc/src/sgml/mvcc.sgml --- b/doc/src/sgml/mvcc.sgml *************** COMMIT; *** 422,429 **** <para> This level is different from Read Committed in that a query in a repeatable read transaction sees a snapshot as of the start of the <emphasis>transaction</>, not as of the start ! of the current query within the transaction. Thus, successive <command>SELECT</command> commands within a <emphasis>single</> transaction see the same data, i.e., they do not see changes made by other transactions that committed after their own transaction started. --- 422,430 ---- <para> This level is different from Read Committed in that a query in a repeatable read transaction sees a snapshot as of the start of the + first non-transaction-control statement in the <emphasis>transaction</>, not as of the start ! of the current statement within the transaction. Thus, successive <command>SELECT</command> commands within a <emphasis>single</> transaction see the same data, i.e., they do not see changes made by other transactions that committed after their own transaction started.
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