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enable_* MergeTree table settings

These settings are available in system.merge_tree_settings and are autogenerated from ClickHouse source.

enable_adaptive_codec_selection

Experimental feature
Type
Bool
Default
0
Version history
VersionDefault valueComment
26.80New setting.

When enabled, merges and mutations choose a codec per block for columns that use the default codec (no CODEC clause, or CODEC(Default)). The candidates are the table’s default codec (see the default_compression_codec setting), NONE, and specialized codecs suited to the column type. The smallest output wins. Compression is therefore never worse than the default, and incompressible blocks are stored raw. A column whose default codec includes encryption (e.g. AES_128_GCM_SIV) is never selected adaptively, so encryption is always applied. Per-block codecs are reported by the mergeTreeCodecBlockCounts table function.

enable_index_granularity_compression

Type
Bool
Default
1

Compress in memory values of index granularity if it is possible

enable_max_bytes_limit_for_min_age_to_force_merge

Type
Bool
Default
1
Version history
VersionDefault valueComment
26.21Limit part sizes even with min_age_to_force_merge_seconds by default
25.10Added new setting to limit max bytes for min_age_to_force_merge.
25.10New setting

If settings min_age_to_force_merge_seconds and min_age_to_force_merge_on_partition_only should respect setting max_bytes_to_merge_at_max_space_in_pool.

Possible values:

  • true
  • false

enable_mixed_granularity_parts

Type
Bool
Default
1

Enables or disables transitioning to control the granule size with the index_granularity_bytes setting. Before version 19.11, there was only the index_granularity setting for restricting granule size. The index_granularity_bytes setting improves ClickHouse performance when selecting data from tables with big rows (tens and hundreds of megabytes). If you have tables with big rows, you can enable this setting for the tables to improve the efficiency of SELECT queries.

enable_replacing_merge_with_cleanup_for_min_age_to_force_merge

Experimental feature
Type
Bool
Default
0
Version history
VersionDefault valueComment
25.30New setting to allow automatic cleanup merges for ReplacingMergeTree

Whether to use CLEANUP merges for ReplacingMergeTree when merging partitions down to a single part. Requires allow_experimental_replacing_merge_with_cleanup, min_age_to_force_merge_seconds and min_age_to_force_merge_on_partition_only to be enabled.

Possible values:

  • true
  • false

enable_the_endpoint_id_with_zookeeper_name_prefix

Type
Bool
Default
0

Enable the endpoint id with zookeeper name prefix for the replicated merge tree table.

enable_vertical_merge_algorithm

Type
UInt64
Default
1

Enable usage of Vertical merge algorithm.

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