docs: clarify when MVCC snapshot is taken

Report by Álvaro Hernández Tortosa
This commit is contained in:
Bruce Momjian 2015-03-24 20:56:09 -04:00
parent 843cd0bfe6
commit 66c8040d50

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@ -422,8 +422,9 @@ COMMIT;
<para> <para>
This level is different from Read Committed in that a query in a 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 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 <emphasis>transaction</>, not as of the start
of the current query within the transaction. Thus, successive of the current statement within the transaction. Thus, successive
<command>SELECT</command> commands within a <emphasis>single</> <command>SELECT</command> commands within a <emphasis>single</>
transaction see the same data, i.e., they do not see changes made by transaction see the same data, i.e., they do not see changes made by
other transactions that committed after their own transaction started. other transactions that committed after their own transaction started.