diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/logicaldecoding.sgml | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml index 80eb96d609a..da23f89ca32 100644 --- a/doc/src/sgml/logicaldecoding.sgml +++ b/doc/src/sgml/logicaldecoding.sgml @@ -794,20 +794,25 @@ typedef void (*LogicalDecodeMessageCB) (struct LogicalDecodingContext *ctx, <command>COMMIT PREPARED</command> time. To signal that decoding should be skipped, return <literal>true</literal>; <literal>false</literal> otherwise. When the callback is not - defined, <literal>false</literal> is assumed (i.e. nothing is - filtered). + defined, <literal>false</literal> is assumed (i.e. no filtering, all + transactions using two-phase commit are decoded in two phases as well). <programlisting> typedef bool (*LogicalDecodeFilterPrepareCB) (struct LogicalDecodingContext *ctx, + TransactionId xid, const char *gid); </programlisting> - The <parameter>ctx</parameter> parameter has the same contents as for the - other callbacks. The <parameter>gid</parameter> is the identifier that later - identifies this transaction for <command>COMMIT PREPARED</command> or - <command>ROLLBACK PREPARED</command>. + The <parameter>ctx</parameter> parameter has the same contents as for + the other callbacks. The parameters <parameter>xid</parameter> + and <parameter>gid</parameter> provide two different ways to identify + the transaction. The later <command>COMMIT PREPARED</command> or + <command>ROLLBACK PREPARED</command> carries both identifiers, + providing an output plugin the choice of what to use. </para> <para> - The callback has to provide the same static answer for a given - <parameter>gid</parameter> every time it is called. + The callback may be invoked multiple times per transaction to decode + and must provide the same static answer for a given pair of + <parameter>xid</parameter> and <parameter>gid</parameter> every time + it is called. </para> </sect3> @@ -1219,9 +1224,11 @@ stream_commit_cb(...); <-- commit of the streamed transaction </para> <para> - Optionally the output plugin can specify a name pattern in the - <function>filter_prepare_cb</function> and transactions with gid containing - that name pattern will not be decoded as a two-phase commit transaction. + Optionally the output plugin can define filtering rules via + <function>filter_prepare_cb</function> to decode only specific transaction + in two phases. This can be achieved by pattern matching on the + <parameter>gid</parameter> or via lookups using the + <parameter>xid</parameter>. </para> <para> |