mysqlnd_ms_query_is_select(3) [php man page]

MYSQLND_MS_QUERY_IS_SELECT(3)						 1					     MYSQLND_MS_QUERY_IS_SELECT(3)

mysqlnd_ms_query_is_select - Find whether to send the query to the master, the slave or the last used MySQL server

SYNOPSIS

       int mysqlnd_ms_query_is_select (string  $query)

DESCRIPTION

	Finds whether to send the query to the master, the slave or the last used MySQL server.

	The plugins built-in read/write split mechanism will be used to analyze the query string to make a recommendation where to send the query.
       The built-in read/write split mechanism is very basic and simple. The plugin will recommend sending all queries to  the	MySQL  replication
       master  server  but  those which begin with SELECT, or begin with a SQL hint which enforces sending the query to a slave server. Due to the
       basic but fast algorithm the plugin may propose to run some read-only statements such as SHOW TABLES on the replication master.

PARAMETERS

	      o $query
		- Query string to test.

RETURN VALUES

	A return value of MYSQLND_MS_QUERY_USE_MASTER indicates that the query should be send to the MySQL replication master server. The function
       returns	a  value  of  MYSQLND_MS_QUERY_USE_SLAVE  if  the  query  can  be  run	on  a slave because it is considered read-only. A value of
       MYSQLND_MS_QUERY_USE_LAST_USED is returned to recommend running the query on the last used server. This can either be a	MySQL  replication
       master server or a MySQL replication slave server.

	If   read   write   splitting	has   been   disabled	by   setting   mysqlnd_ms.disable_rw_split,   the   function  will  always  return
       MYSQLND_MS_QUERY_USE_MASTER or MYSQLND_MS_QUERY_USE_LAST_USED.

EXAMPLES

       Example #1

	      mysqlnd_ms_query_is_select(3) example

	      <?php
	      function is_select($query)
	      {
	       switch (mysqlnd_ms_query_is_select($query))
	       {
		case MYSQLND_MS_QUERY_USE_MASTER:
		 printf("'%s' should be run on the master.
", $query);
		 break;
		case MYSQLND_MS_QUERY_USE_SLAVE:
		 printf("'%s' should be run on a slave.
", $query);
		 break;
		case MYSQLND_MS_QUERY_USE_LAST_USED:
		 printf("'%s' should be run on the server that has run the previous query
", $query);
		 break;
		default:
		 printf("No suggestion where to run the '%s', fallback to master recommended
", $query);
		 break;
	       }
	      }

	      is_select("INSERT INTO test(id) VALUES (1)");
	      is_select("SELECT 1 FROM DUAL");
	      is_select("/*" . MYSQLND_MS_LAST_USED_SWITCH . "*/SELECT 2 FROM DUAL");
	      ?>

	      The above example will output:

	      INSERT INTO test(id) VALUES (1) should be run on the master.
	      SELECT 1 FROM DUAL should be run on a slave.
	      /*ms=last_used*/SELECT 2 FROM DUAL should be run on the server that has run the previous query

SEE ALSO

       Predefined Constants, user filter .Runtime configuration, mysqlnd_ms.disable_rw_split, mysqlnd_ms.enable.

PHP Documentation Group 											     MYSQLND_MS_QUERY_IS_SELECT(3)

Check Out this Related Man Page

MYSQLND_MS_GET_LAST_GTID(3)						 1					       MYSQLND_MS_GET_LAST_GTID(3)

mysqlnd_ms_get_last_gtid - Returns the latest global transaction ID

SYNOPSIS

       string mysqlnd_ms_get_last_gtid (mixed  $connection)

DESCRIPTION

	Returns a global transaction identifier which belongs to a write operation no older than the last write performed by the client. It is not
       guaranteed that the global transaction identifier is identical to that one created for the last write transaction performed by the client.

PARAMETERS

	      o $connection
		- A PECL/mysqlnd_ms connection handle to a MySQL server of the type PDO_MYSQL, mysqli> or  ext/mysql.  The  connection	handle	is
		obtained  when	opening  a  connection	with a host name that matches a mysqlnd_ms configuration file entry using any of the above
		three MySQL driver extensions.

RETURN VALUES

	Returns a global transaction ID (GTID) on success. Otherwise, returns FALSE.

	The function mysqlnd_ms_get_last_gtid(3) returns the GTID obtained when executing the SQL statement from the fetch_last_gtid entry of  the
       global_transaction_id_injection section from the plugins configuration file.

	The function may be called after the GTID has been incremented.

NOTES

       Note

	      mysqlnd_ms_get_last_gtid(3)  requires  PHP  >= 5.4.0 and PECL mysqlnd_ms >= 1.2.0. Internally, it is using a mysqlnd library C func-
	      tionality not available with PHP 5.3.

	       Please note, all MySQL 5.6 production versions do not provide clients with enough information to use GTIDs  for	enforcing  session
	      consistency. In the worst case, the plugin will choose the master only.

EXAMPLES

       Example #1

	      mysqlnd_ms_get_last_gtid(3) example

	      <?php
	      /* Open mysqlnd_ms connection using mysqli, PDO_MySQL or mysql extension */
	      $mysqli = new mysqli("myapp", "username", "password", "database");
	      if (!$mysqli)
		/* Of course, your error handling is nicer... */
		die(sprintf("[%d] %s
", mysqli_connect_errno(), mysqli_connect_error()));

	      /* auto commit mode, transaction on master, GTID must be incremented */
	      if (!$mysqli->query("DROP TABLE IF EXISTS test"))
		die(sprintf("[%d] %s
", $mysqli->errno, $mysqli->error));

	      printf("GTID after transaction %s
", mysqlnd_ms_get_last_gtid($mysqli));

	      /* auto commit mode, transaction on master, GTID must be incremented */
	      if (!$mysqli->query("CREATE TABLE test(id INT)"))
		die(sprintf("[%d] %s
", $mysqli->errno, $mysqli->error));

	      printf("GTID after transaction %s
", mysqlnd_ms_get_last_gtid($mysqli));
	      ?>

SEE ALSO

       Global Transaction IDs.

PHP Documentation Group 											       MYSQLND_MS_GET_LAST_GTID(3)

Linux and UNIX Man Pages

mysqlnd_ms_query_is_select(3) [php man page]

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