Where to put slow query logs in MySQL?

Where to put slow query logs in MySQL?

You must ensure that the variable slow_query_log is set to ON, while the slow_query_log_file determines the path where you need to place your slow query logs. If this variable is not set, it will use the DATA_DIR of your MySQL data directory.

How to write slow admin statements in MySQL?

If a log file already is open, it is closed and the new file is opened. The server writes less information to the slow query log if you use the –log-short-format option. To include slow administrative statements in the slow query log, enable the log_slow_admin_statements system variable.

Can a file name affect the slow query log?

Setting the log file name has no effect on logging if FILE is not selected as an output destination. If the slow query log is enabled and FILE is selected as an output destination, each statement written to the log is preceded by a line that begins with a # character and has these fields (with all fields on a single line):

How to enable slow slave update in MySQL?

To enable logging slave updates, use the log_slow_slave_statements option. In MySQL 5.6.10/5.5 and earlier this can only be set in the MySQL configuration file and requires a restart to take effect. In 5.6.11/5.7 and later, the option can be set dynamically.

Why does MySQL make my website so slow?

But they are also infamous for their performance issues. Apache, PHP & MySQL often cause high server load, and drag down the website. Here at Bobcares, we help website owners, digital marketers and web hosts recover from and prevent website performance issues.

Why are MySQL queries blocked during off peak hours?

So we perform such a fix only during off peak hours, and if needed by posting a maintenance schedule notice to prevent online business loss. There are also some situations where queries are blocked due to corruption in session tables, cache tables, etc.

Are there any performance issues with MySQL database?

Performance issues are common problems when administering MySQL databases. Sometimes these problems are, in fact, due to slow queries. In this blog, we’ll deal with slow queries and how to identify these. MySQL has the capability to filter and log slow queries.

How to identify performance issues with slow queries?

Performance issues are common problems when administering MySQL databases. Sometimes these problems are, in fact, due to slow queries. In this blog, we’ll deal with slow queries and how to identify these.

Can a 10 second query cause performance degradation?

The slow queries definition might differ in different cases since there are certain occasions that even a 10 second query is acceptable and still not slow. However, if your application is an OLTP, it’s very common that a 10 second or even a 5 second query is an issue or causes performance degradation to your database.

What does it mean when a query is slow?

The slow query logs will show you a list of queries that have been identified as slow, based on the given values in the system variables as mentioned earlier. The slow queries definition might differ in different cases since there are certain occasions that even a 10 second query is acceptable and still not slow.

How to control the time zone of the slow query log?

It is not possible to change the destination dynamically, so a restart of MySQL is required before the change takes effect. In MySQL 5.7.2 and later, the time zone used for the timestamps in the Slow Query Log can be controlled using the log_timestamps option.

How is the query time measured in MySQL?

The query time is measured from after any initial table locks have been acquired. Queries are written to the slow query log after all locks have been released. This reduces the time locks are held, but means that two queries requiring the same table locks may end up in the slow query log in opposite order.