DROP_STATISTICS

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

Caution: Before you drop statistics, be aware that sstatistics can be time consuming to regenerate.

Syntax

DROP_STATISTICS ('[ scope ]'[, 'category'] [, 'column[,...]' )

Parameters

scope

Specifies the target table as follows:

[schema.]table

If set to an empty string, Vertica drops statistics for projections of all database tables.
category

The category of statistics to drop for the named table, one of the following:

  • BASE (default) drops histograms and row counts (min/max column values, histogram).
  • HISTOGRAMS drops only histograms. Row counts statistics remain.
  • ALL drops all statistics.
column

The name of a column in table, typically a predicate column. You can specify multiple comma-delimited columns. Vertica narrows the scope of dropped statistics to the specified columns only.

Privileges

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