pg_statistic

The pg_statistic catalog provides information about table statistics.

Column name	Data type	Description
starelid	oid (references pg_class.oid)	The table or index to which the described column belongs.
staattnum	int2 (references pg_attribute.attnum)	The number of the described column.
stainherit	bool	Specifies whether statistics include values from child tables (TRUE), or only from the specified relation (FALSE).
stanullfrac	float4	The fraction of the column’s entries that are NULL.
stawidth	int4	The average stored width, in bytes, of non-null entries.
stadistinct	float4	The number of distinct non-NULL data values. The possible values are: Positive – Exact count. Negative – The multiplier of table rows. 0 - Unknown.
stakindN	int2	A code number indicating the kind of statistics stored in the N-th slot of the pg_statistic row.
staopN	oid (references pg_operator.oid)	An operator used to derive statistics for the N-th slot. 0 – Not required.
stacollN	oid (references pg_collation.oid)	Collation used when deriving statistics for the N-th slot. 0 – For non-collatable data.
stanumbersN	float4[]	Numerical statistics for the N-th slot, or NULL if not applicable.
stavaluesN	anyarray	Data values for the N-th slot, or NULL if the slot stores no values. Actual element types match the column’s datatype or related types.