Not the answer you need?
Register and ask your own question!

SHOW DATABASES (any queries on table_schema) extremely slow only on 2/3 nodes

akangakang EntrantCurrent User Role Beginner
We have a Percona XtraDB 5.6 cluster of 3 nodes. For some reason on two nodes, it takes an abnormal amount of time to run queries that involve tables in the information_schema database.

For ex, running "SHOW DATABASES" takes ~5min on node2 and ~3min on node3 whereas on node1, it takes ~0.02sec.

Node1 has a system memory of 8gb and innodb buffer pool size of 3gb.

Node2 and 3 have a system memory of 4gb and innodb buffer pool size of 2gb.

I know that the information_schema tables are stored in memory. I am theorizing that because of a small innodb buffer pool size, node2 and 3 take a long time to query against information_schema. However, when testing on a test cluster, I cannot reproduce this issue by lowering the innodb buffer pool size.

Has anyone ever experienced and know what the issue may be?
Sign In or Register to comment.

MySQL, InnoDB, MariaDB and MongoDB are trademarks of their respective owners.
Copyright ©2005 - 2020 Percona LLC. All rights reserved.