8 ms·
ClickHouse uses skip indexes. They basically answer the question "is the value I'm seeking not in the block." For example, there are a couple varieties of Bloo
by hodgesrm 5y ago
ClickHouse uses skip indexes. They basically answer the question "is the value I'm seeking not in the block."
For example, there are a couple varieties of Bloom filters, which allow you to test for presence of string sequences in blocks. This allows ClickHouse to skip reading and uncompressing blocks (actually called granules) unnecessarily.