How do I determine the right value for innodb_sync_array_size in MySQL? We have version 5.7 deployed on AWS RDS with 32 vCPUs, and it sees about 26 concurrent threads on average. When I measure waits using: show engine innodb mutex, the total number of waits increases by about 143k / hour.

The MySQL documentation does say that a higher number will help with high concurrency and wait situation, but I cannot find any documentation on what to set this number and how to determine whether this will indeed help me.

  • Are you getting a lot of "waiting threads"? (I have not heard of anyone changing it from 1.)
    – Rick James
    Commented Aug 29, 2020 at 6:35
  • @RickJames How do I measure "waiting threads"? Pretty much all the Percona webinar slides have the value set to 16 and they say it should be 16, but don't give an explanation either. Commented Aug 29, 2020 at 7:32
  • The AWS documentation at aws.amazon.com/blogs/database/… also recommends it. My Load Avg 1 min chart shows the count reaching in the range of 14 - 16 on a regular basis. It's still <32 (vCPU). Not sure whether I'd get any performance gains or wait time reduction though. Commented Aug 29, 2020 at 8:20

1 Answer 1


This might help in understanding it more in details.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.