This topic describes bitmap indexes in ApsaraDB for SelectDB and how to use the bitmap indexes.
Background information
A bitmap index is a data structure that can be quickly created and accelerates queries. This topic describes how to create a bitmap index. This topic also describes the usage notes and common issues about creating a bitmap index.
Create a bitmap index
Syntax:
CREATE INDEX [IF NOT EXISTS] <index_name> ON <table_name> (<column>) USING BITMAP;The following table describes the parameters.
Parameter | Description |
table_name | The name of the table for which you want to create a bitmap index. |
column | The name of the column on which you want to create a bitmap index. |
Query information about a bitmap index
Syntax:
SHOW INDEX FROM [db_name.]<table_name>;Delete a bitmap index
Syntax:
DROP INDEX [IF EXISTS] index_name ON [db_name.]table_name;Usage notes
You can create a bitmap index only on a single column.
Bitmap indexes can be applied to all columns in the Duplicate or Unique key model and key columns in the Aggregate key model.
Bitmap indexes take effect only on data in the Segment V2 format. When you create a bitmap index for a table, the storage format of the table is converted to the Segment V2 format by default.
Bitmap indexes support the following data types:
TINYINTSMALLINTINTBIGINTCHARVARCHARDATEDATETIMELARGEINTDECIMALBOOL