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1.6 KiB
1.6 KiB
system.data_skipping_indices
包含有关所有表中现有数据跳过索引的信息.
列信息:
database
(String) — 数据库名称.table
(String) — 数据表名称.name
(String) — 索引名称.type
(String) — 索引类型.expr
(String) — 索引计算表达式.granularity
(UInt64) — 块中颗粒的数量.data_compressed_bytes
(UInt64) — 压缩数据的大小, 以字节为单位.data_uncompressed_bytes
(UInt64) — 解压缩数据的大小, 以字节为单位.marks_bytes
(UInt64) — 标记的大小, 以字节为单位.
示例
SELECT * FROM system.data_skipping_indices LIMIT 2 FORMAT Vertical;
Row 1:
──────
database: default
table: user_actions
name: clicks_idx
type: minmax
expr: clicks
granularity: 1
data_compressed_bytes: 58
data_uncompressed_bytes: 6
marks: 48
Row 2:
──────
database: default
table: users
name: contacts_null_idx
type: minmax
expr: assumeNotNull(contacts_null)
granularity: 1
data_compressed_bytes: 58
data_uncompressed_bytes: 6
marks: 48