diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/func.sgml | 45 | ||||
| -rw-r--r-- | doc/src/sgml/logicaldecoding.sgml | 38 |
2 files changed, 83 insertions, 0 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index c6017e61aee..f60d5784fdd 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -18255,6 +18255,51 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup()); </entry> </row> + <row> + <entry id="pg-logical-emit-message-text"> + <indexterm> + <primary>pg_logical_emit_message</primary> + </indexterm> + <literal><function>pg_logical_emit_message(<parameter>transactional</parameter> <type>bool</type>, <parameter>prefix</parameter> <type>text</type>, <parameter>content</parameter> <type>text</type>)</function></literal> + </entry> + <entry> + void + </entry> + <entry> + Emit text logical decoding message. This can be used to pass generic + messages to logical decoding plugins through WAL. The parameter + <parameter>transactional</parameter> specifies if the message should + be part of current transaction or if it should be written immediately + and decoded as soon as the logical decoding reads the record. The + <parameter>prefix</parameter> is textual prefix used by the logical + decoding plugins to easily recognize interesting messages for them. + The <parameter>content</parameter> is the text of the message. + </entry> + </row> + + <row> + <entry id="pg-logical-emit-message-bytea"> + <indexterm> + <primary>>pg_logical_emit_message</primary> + </indexterm> + <literal><function>>pg_logical_emit_message(<parameter>transactional</parameter> <type>bool</type>, <parameter>prefix</parameter> <type>text</type>, <parameter>content</parameter> <type>bytea</type>)</function></literal> + </entry> + <entry> + void + </entry> + <entry> + Emit binary logical decoding message. This can be used to pass generic + messages to logical decoding plugins through WAL. The parameter + <parameter>transactional</parameter> specifies if the message should + be part of current transaction or if it should be written immediately + and decoded as soon as the logical decoding reads the record. The + <parameter>prefix</parameter> is textual prefix used by the logical + decoding plugins to easily recognize interesting messages for them. + The <parameter>content</parameter> is the binary content of the + message. + </entry> + </row> + </tbody> </tgroup> </table> diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml index 45fdfeb13fd..8306d9ffaa0 100644 --- a/doc/src/sgml/logicaldecoding.sgml +++ b/doc/src/sgml/logicaldecoding.sgml @@ -363,6 +363,7 @@ typedef struct OutputPluginCallbacks LogicalDecodeBeginCB begin_cb; LogicalDecodeChangeCB change_cb; LogicalDecodeCommitCB commit_cb; + LogicalDecodeMessageCB message_cb; LogicalDecodeFilterByOriginCB filter_by_origin_cb; LogicalDecodeShutdownCB shutdown_cb; } OutputPluginCallbacks; @@ -602,6 +603,43 @@ typedef bool (*LogicalDecodeFilterByOriginCB) ( more efficient. </para> </sect3> + + <sect3 id="logicaldecoding-output-plugin-message"> + <title>Generic Message Callback</title> + + <para> + The optional <function>message_cb</function> callback is called whenever + a logical decoding message has been decoded. +<programlisting> +typedef void (*LogicalDecodeMessageCB) ( + struct LogicalDecodingContext *, + ReorderBufferTXN *txn, + XLogRecPtr message_lsn, + bool transactional, + const char *prefix, + Size message_size, + const char *message +); +</programlisting> + The <parameter>txn</parameter> parameter contains meta information about + the transaction, like the time stamp at which it has been committed and + its XID. Note however that it can be NULL when the message is + non-transactional and the XID was not assigned yet in the transaction + which logged the message. The <parameter>lsn</parameter> has WAL + position of the message. The <parameter>transactional</parameter> says + if the message was sent as transactional or not. + The <parameter>prefix</parameter> is arbitrary null-terminated prefix + which can be used for identifying interesting messages for the current + plugin. And finally the <parameter>message</parameter> parameter holds + the actual message of <parameter>message_size</parameter> size. + </para> + <para> + Extra care should be taken to ensure that the prefix the output plugin + considers interesting is unique. Using name of the extension or the + output plugin itself is often a good choice. + </para> + </sect3> + </sect2> <sect2 id="logicaldecoding-output-plugin-output"> |