database - 了解 Cloud Spanner INDEX(索引)中的 INTERLEAVE

Question

有什么区别

CREATE INDEX SongsBySingerSongName 
          ON Songs(SingerId, SongName),
          INTERLEAVE IN Singers

和

CREATE INDEX SongsBySingerSongName 
          ON Songs(SingerId, SongName)

Answer 1

Cloud Spanner 会将索引条目与数据表交织在一起。

这意味着每个 SingerId 的 SongsBySingerSongName 索引条目都位于一起。

来自 Spanner > Documentation > Data Definition Language :

Like interleaved tables, entries in an interleaved indexes are stored with the corresponding row of the parent table. See database splits for more details.

和

When should you create an interleaved index? If the index key that you want to use for index operations matches the key of a table, you might want to interleave the index in that table if the row in the table should have a data locality relationship with the corresponding indexed rows.