Memory Issue on RDS MYSQL 8

Question

Hi Team,

We are facing a memory issue with the RDS mysql 8.0.33:

It is an r6g.large instance size RDS. We checked the memory consumption using the query below:

SELECT
  TABLE_NAME AS `Table`,
  ROUND((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024) AS `Size (MB)`,
  ROUND((INDEX_LENGTH) / 1024 / 1024) AS `Size (MB)`
FROM
  information_schema.TABLES
WHERE
  TABLE_SCHEMA = "testenv_prod"
ORDER BY
  (DATA_LENGTH + INDEX_LENGTH) DESC;

The indexes that are consuming memory amount to 4172MB. We have no clues or evidence about where the memory leak is occurring. When we reboot the instance, it goes back to 16GB, but within 5-6 hours, it drops to 1-2GB.

Regina · Answer

Hi, 
The issue seems to be related to the indexes, with a total consumption of 4172MB.
Consider reviewing the indexes on the tables in the "testenv_prod" schema. Check for any unusually large or redundant indexes.
Also I recommend you to check the MySQL error log for any entries or warnings related to memory issues. The error log might provide additional clues about what is happening during the memory drop.
And the last, Review your queries, stored procedures and other application code for any unoptimized queries or operations that could be paging/caching data in memory over time.

Memory Issue on RDS MYSQL 8

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