VALIDATE_STATISTICS

Validates statistics in the XML file generated by EXPORT_STATISTICS.

Syntax

VALIDATE_STATISTICS ( 'XML‑file' )

Parameters

XML‑file

the path and name of the XML file that contains the statistics to validate.

Privileges

Superuser

Reporting Valid Statistics

The following example shows the results when the statistics are valid:

=> SELECT EXPORT_STATISTICS('cust_dim_stats.xml','customer_dimension');
    EXPORT_STATISTICS
-----------------------------------
 Statistics exported successfully
(1 row)
=> SELECT VALIDATE_STATISTICS('cust_dim_stats.xml');
 VALIDATE_STATISTICS
---------------------
(1 row)

Identifying Invalid Statistics

If VALIDATE_STATISTICS is unable to read a document's XML, it throws this error:

=> SELECT VALIDATE_STATISTICS('/home/dbadmin/stats.xml');
                       VALIDATE_STATISTICS
----------------------------------------------------------------------------
Error validating statistics file: At line 1:1. Invalid document structure
(1 row)

If some table statistics are invalid, VALIDATE_STATISTICS returns a report that identifies them. In the following example, the function reports that attributes distinct, buckets, rows, count, and distinctCount cannot be negative numbers. 

=> SELECT VALIDATE_STATISTICS('/stats.xml');
WARNING 0:  Invalid value '-1' for attribute 'distinct' under column 'public.t.x'. 
   Please use a positive value.
WARNING 0:  Invalid value '-1' for attribute 'buckets' under column 'public.t.x'. 
   Please use a positive value.
WARNING 0:  Invalid value '-1' for attribute 'rows' under column 'public.t.x'. 
   Please use a positive value.
WARNING 0:  Invalid value '-1' for attribute 'count' under bound '1', column 'public.t.x'. 
   Please use a positive value.
WARNING 0:  Invalid value '-1' for attribute 'distinctCount' under bound '1', column 'public.t.x'. 
   Please use a positive value.
 VALIDATE_STATISTICS
---------------------
 (1 row)

In this case, run ANALYZE_STATISTICS on the table again to create valid statistics.

See Also