Why does my SQL query take so long to execute?

Why does my SQL query take so long to execute?

There are a number of things that may cause a query to take longer time to execute: Table lock – The table is locked, by global lock or explicit table lock when the query is trying to access it. Deadlock – A query is waiting to access the same rows that are locked by another query.

How do I enable slow query?

Enable the Slow Query Log

1. Log in to your server as the root user via SSH.
2. Open the my.cnf file with a text editor and add the following block of code under the mysqld section:
3. Create the /var/log/mysql-slow.log file and set its user as the mysql user.
4. Restart MySQL or MariaDB.
5. Start monitoring the slow query logfile.

How do I stop a query in MySQL?

How to Kill MySQL Queries

1. Show processlist;
2. Then review the “Time” field to find the longest running query.
3. Next, run the following command to kill it: kill thread_ID;

How do I write a better SQL query?

Some of the rules for formatting a query are given below:

1. Put each statement in the query in a new line.
2. Put SQL keywords in the query in uppercase.
3. Use CamelCase capitalization in the query and avoid underscore(Write ProductName and not Product_Name).

Why are there so many long running queries in MySQL?

Long running queries/statements/transactions are sometimes inevitable in a MySQL environment. In some occasions, a long running query could be a catalyst to a disastrous event. If you care about your database, optimizing query performance and detecting long running queries must be performed regularly.

Why does MySQL take too long to send data?

As you can see, the SELECT statement used the index and read only 1482 rows. Yet, the query spent 7.536960 seconds sending the data. It is like the query read much more rows it needed.

How long does it take to execute MySQL Query?

Here is what I am trying to execute: I have tried reducing the SELECT * to a SELECT open_hours.id, open_times.meal_type since in reality that’s the only number I’m trying to get right now. It gets me the results in roughly 30 seconds, which still sounds like a lot to me.

What can I do to make MySQL Query faster?

To make the query faster in your case there have three things you can do. Don’t know it will help you or not but According to SQL optimizing query concepts, it must help. Create CLUSTERED INDEX for all your tables. Cluster index makes the SELECT query faster at 30:70 of ratio.