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Data Skipping Indices
Data skipping indices allow ClickHouse to skip entire blocks of data that don't match query conditions, even for columns not in the sorting key. Use indices like minmax for ranges, set for equality filters, and ngrambf_v1 for string searches. Add indices for columns frequently filtered but not in the sorting key, and monitor their effectiveness.
Data skipping indices are secondary indices that help ClickHouse skip data blocks for columns not in the sorting key. They're essential for optimizing queries that filter by columns that can't be included in the sorting key.
What are Data Skipping Indices?
Data skipping indices store metadata about data blocks, allowing ClickHouse to determine whether a block might contain matching rows without reading it.