allow_experimental_adaptive_codec_selection
When enabled, merges and mutations choose a codec per block for columns that use the default codec (noCODEC 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 withis_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 experimentalsupport_phrase_search argument
which stores token positions to support exact phrase matching.