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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