12.15. GTID Functions

The functions described in this section are used with GTID-based replication (available in MySQL 5.6.5 and later). For more information about GTIDs and how these functions are used, see Section 16.1.3, "Replication with Global Transaction Identifiers".

Note

The union of two GTID sets is simply their string representations joined together with an interposed comma. In other words, you can define a very simple function for obtaining the union of two GTID sets like this:

CREATE FUNCTION GTID_UNION(g1 TEXT, g2 TEXT)     RETURNS TEXT DETERMINISTICRETURN CONCAT(g1,',',g2);

Table 12.19. GTID Functions

Name	Description
`GTID_SUBSET()`	Return true if all GTIDs in subset are also in set; otherwise false.
`GTID_SUBTRACT()`	Return all GTIDs in set that are not in subset.
`SQL_THREAD_WAIT_AFTER_GTIDS()`(deprecated 5.6.9)	OBSOLETE: Replaced by WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS()
`WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS()`	Wait until the slave SQL thread has executed all the given GTIDs. Returns: the number of events that were executed (or NULL, if GTID mode is not enabled).

GTID_SUBSET(subset,set)

Given two sets of global transaction IDs subset and set, returns true if all GTIDs in subset are also in set. Returns false otherwise.

This function was added in MySQL 5.6.5.
GTID_SUBTRACT(set,subset)

Given two sets of global transaction IDs subset and set, returns only those GTIDs from set that are not in subset.

This function was added in MySQL 5.6.5.
SQL_THREAD_WAIT_AFTER_GTIDS(gtid_set[, timeout])

SQL_THREAD_WAIT_AFTER_GTIDS() was added in MySQL 5.6.5, and replaced by WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS() in MySQL 5.6.9. (Bug #14775984)

For more information, see Section 16.1.3, "Replication with Global Transaction Identifiers".
WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS(gtid_set[, timeout])

Wait until the slave SQL thread has executed all of the transactions whose global transaction identifiers are contained in gtid_set (see Section 16.1.3.1, "GTID Concepts", for a definition of "GTID sets"), or until timeout seconds have elapsed, whichever occurs first. timeout is optional; the default timeout is 0 seconds, in which case the master simply waits until all of the transactions in the GTID set have been executed.

Prior to MySQL 5.6.9, WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS() was named SQL_THREAD_WAIT_AFTER_GTIDS(). (Bug #14775984)

For more information, see Section 16.1.3, "Replication with Global Transaction Identifiers".
```
mysql> SELECT
                    WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS('3E11FA47-71CA-11E1-9E33-C80AA9429562:1-5');        -> 5
```
The return value is the number of transactional events that were executed. Prior to MySQL 5.6.8, this function behaved unpredictably if no timeout was set and it was invoked while GTID-based replication was not active; in MySQL 5.6.8 and later, the function returns NULL whenever gtid_mode is OFF. (Bug #14640065)