DROP_STATISTICS

Removes statistical data on database projections previously generated by ANALYZE_STATISTICS. When you drop this data, the Vertica optimizer creates query plans using default statistics.

This is a meta-function. You must call meta-functions in a top-level SELECT statement.

Behavior type

Syntax

DROP_STATISTICS ('[[[database.]schema.]table]' [, 'category' [, '[column-list]'] )

Parameters

[database.]schema

Database and schema. The default schema is public. If you specify a database, it must be the current database.

table

Table on which to drop statistics. If set to an empty string, Vertica drops statistics for all database tables and their projections.

category

Category of statistics to drop, one of the following:

• ALL (default): Drop all statistics, including histograms and row counts.

• HISTOGRAMS: Drop only histograms. Row count statistics remain.

column-list

Comma-delimited list of columns in table, typically predicate columns. Vertica narrows the scope of dropped statistics to the specified columns. If you omit this parameter or supply an empty string, Vertica drops statistics on all columns.

Privileges

Non-superuser:

• Schema: USAGE

• Table: One of INSERT, DELETE, or UPDATE

Examples

Drop all base statistics for the table store.store_sales_fact:

=> SELECT DROP_STATISTICS('store.store_sales_fact');
 DROP_STATISTICS
-----------------
               0
(1 row)

Drop statistics for all table projections:

=> SELECT DROP_STATISTICS ('');
 DROP_STATISTICS
-----------------
               0
(1 row)

See also