Updated on 2022-12-09 GMT+08:00

Solution to the "Too many parts" Error in Data Tables

Troubleshooting

  1. Log in to the ClickHouse client and check whether abnormal merge exists.

    select database, table, elapsed, progress, merge_type from system.merges;

  2. Do not perform the INSERT operation too frequently, do not insert a small amount of data, and increase the interval for inserting data.
  3. The data table partitions are not properly allocated. As a result, too many partitions are generated and data tables need to be re-partitioned.
  4. If the MERGE operations are not triggered or slow, adjust the following parameters to accelerate them.

    For details, see Accelerating Merge Operations.

    Configuration Item

    Reference Value

    max_threads

    Number of CPU cores x 2

    background_pool_size

    Number of CPU cores

    merge_max_block_size

    The value is an integer multiple of 8192 and is adjusted based on the CPU and memory resources.

    cleanup_delay_period

    Set this parameter to a value that is appropriately less than the default value 30.

Changing the Value of parts_to_throw_insert

Increase the value of this parameter only in special scenarios. This configuration acts as a warning for potential issues to some extent. If the cluster hardware resources are insufficient and this configuration is not adjusted properly, potential service issues cannot be detected in a timely manner, which may cause other faults and increase the difficulty of fault recovery.

Log in to FusionInsight Manager and choose Cluster > Services > ClickHouse. Click Configurations then All Configurations. Click ClickHouseServer > Customization, find the clickhouse-config-customize parameter, add the following configuration, save it, and restart the service.

Name

Value

merge_tree.parts_to_throw_insert

Memory of ClickHouse instances/32 GB x 300 (conservative estimation)

Verify the modification.

Log in to the ClickHouse client and run the select * from system.merge_tree_settings where name = 'parts_to_throw_insert'; command.