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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)
