7. Checking Partition Number and Data Skew

This step checks whether there are enough partitions and if data is properly balanced across your cluster.

1. Check the total core-to-partition ratio per leaf for the database that is having trouble:

   • Run SHOW PARTITIONS on the database in question and compare that with the total number of cores in your cluster.

   • Is this ratio at least 1:1? If you have high concurrency, consider increasing the concurrency from 2, 3, or 4 to 1 core to partition ratio.

2. Check that your data is balanced across the cluster properly by running EXPLAIN REBALANCE PARTITIONS on the database in question. If you see a non-empty set, run REBALANCE PARTITIONS on the database.

3. Check that your data is redundant by running EXPLAIN RESTORE REDUNDANCY. If you see a non-empty set, run RESTORE REDUNDANCY.

4. Data Skew: refer to the Detecting and Resolving Data Skew.