Sumit Dey
Sarkar
10 May 2023
MySQLIn this tutorial we will see tips to increase server sort buffer size.
Resolving the 'Mysql Out of Sort Memory' Error: Tips to Increase Server Sort Buffer Size
If you are a MySQL user, you may have encountered the error message "Mysql Out of sort memory, consider increasing server sort buffer size." This error occurs when MySQL is unable to allocate enough memory to sort data during a query. In the following article, we' will discuss about what this error means, why this error happens, and how you can fix this error so that your MySQL server runs well.
What does the error message mean?
The "Mysql Out of sort memory, consider increasing server sort buffer size" error message indicates that MySQL has run out of memory while trying to sort data during a query. Sorting data is an essential part of many queries, and MySQL uses a buffer to hold the data being sorted. MySQL gives this error if the buffer isn't big enough to hold all the data.
Why does the error occur?
Most of the time, such error comes because the size of the server's sort buffer is too small. The server sort buffer size is the amount of memory allocated by MySQL to sort data during a query. If this number becomes too small, MySQL will not be able to to sort all the data, and these results in the error message.
The data being sorted is too big is another reason for this mistake. When MySQL sorts data, it reads all the data into memory before sorting it. The memory limit may have been reached because the data set is too large.
How to fix the error?
There are several ways to fix the "Mysql Out of sort memory, consider increasing server sort buffer size" error:
1) Increase the server sort buffer size:
As the error message suggests, you can increase the server sort buffer size to allocate more memory for sorting. Simply include the following instruction in your my.cnf file:
sort_buffer_size=1MReplace "1M" with the desired buffer size, in megabytes. The server's buffer space should not be bigger than the server's memory.
2) Optimize your query:
If optimising your query failed after raising the buffer size, try increasing the buffer size again. This involves analyzing the query and identifying ways to reduce the amount of data being sorted. To speed the process of sorting, for example, you can create an index in the columns getting sorted.
3) Use external sorting:
Data that exceeds the memory's capacity must be sorted externally. This involves sorting the data on disk rather than in memory. MySQL has a built-in method for external sorting called "filesort." To use this method, you can add the following line to your my.cnf file:
myisam_sort_buffer_size=1MReplace "1M" with the desired buffer size, in megabytes.
In conclusion, the "Mysql Out of sort memory, consider increasing server sort buffer size" error message can be resolved by increasing the server sort buffer size, optimizing your query, or using external sorting. By implementing these solutions, you can ensure that your MySQL server runs smoothly and efficiently.
