# MASTER\_POS\_WAIT

## Syntax

```sql
MASTER_POS_WAIT(log_name,log_pos[,timeout,["connection_name"]])
```

## Description

This function is useful in [replication](https://mariadb.com/docs/server/server-usage/storage-engines/myrocks/myrocks-and-replication) for controlling primary/replica synchronization. It blocks until the replica has read and applied all updates up to the specified position (`log_name,log_pos`) in the primary log. The return value is the number of log events the replica had to wait for to advance to the specified position. The function returns `NULL` if the replica SQL thread is not started, the replica's primary information is not initialized, the arguments are incorrect, or an error occurs. It returns -1 if\
the timeout has been exceeded. If the replica SQL thread stops while`MASTER_POS_WAIT()` is waiting, the function returns `NULL`. If the replica is past the specified position, the function returns immediately.

If a `timeout` value is specified, `MASTER_POS_WAIT()` stops waiting when `timeout` seconds have elapsed. `timeout` must be greater than 0; a zero or negative `timeout` means no `timeout`.

The `connection_name` is used when you are using [multi-source-replication](https://mariadb.com/docs/server/ha-and-performance/standard-replication/multi-source-replication). If you don't specify it, it's set to the value of the [default\_master\_connection](https://mariadb.com/docs/server/ha-and-performance/standard-replication/replication-and-binary-log-system-variables) system variable.

Statements using the `MASTER_POS_WAIT()` function are not [safe for statement-based replication](https://mariadb.com/docs/server/ha-and-performance/standard-replication/unsafe-statements-for-statement-based-replication).

<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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