allow_experimental_* MergeTree table settings

ClickHouse MergeTree table settings in the allow_experimental_* generated group.

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

allow_experimental_adaptive_codec_selection

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. Only integer-like types are currently adaptive. 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.

allow_experimental_replacing_merge_with_cleanup

Allow experimental CLEANUP merges for ReplacingMergeTree with is_deleted column. When enabled, allows using OPTIMIZE ... FINAL CLEANUP to manually merge all parts in a partition down to a single part and removing any deleted rows.

Also allows enabling such merges to happen automatically in the background with settings min_age_to_force_merge_seconds, min_age_to_force_merge_on_partition_only and enable_replacing_merge_with_cleanup_for_min_age_to_force_merge.

allow_experimental_reverse_key

Obsolete setting, does nothing.

allow_experimental_text_index_phrase_search

Allow creating text indexes with the experimental support_phrase_search argument which stores token positions to support exact phrase matching.