How to create index for Map Type Column or one key of it?
[version 21.8.10 revision 54449] #31801
You can create index for map keys, or for map values. Example:
CREATE TABLE test_table
(
id UInt64,
value Map(Int64, String),
index value_key_index mapKeys(value) TYPE bloom_filter GRANULARITY 4
) ENGINE=MergeTree ORDER BY id;
Link to documentation https://clickhouse.com/docs/en/engines/table-engines/mergetree-family/mergetree/#available-types-of-indices.
参考：https://github.com/ClickHouse/ClickHouse/issues/31801
标签：Map,index,Column,create,value,key,ClickHouse From： https://blog.51cto.com/u_15236724/5889952