PG_STATISTIC_EXT¶
PG_STATISTIC_EXT records extended statistics about tables in a database. The range of extended statistics to be collected is specified by users. Only system administrators can access this system catalog.
Parameter | Type | Description |
|---|---|---|
starelid | oid | Table or index which the described column belongs to |
starelkind | "char" | Type of an object |
stainherit | boolean | Whether to collect statistics for objects that have inheritance relationship |
stanullfrac | real | Percentage of column entries that are null |
stawidth | integer | Average stored width, in bytes, of non-null entries |
stadistinct | real | Number of distinct, not-null data values in the column for all DNs
|
stadndistinct | real | Number of unique non-null data values in the dn1 column
|
stakindN | smallint | Code number stating that the type of statistics is stored in Slot N of the pg_statistic row. Value range: 1 to 5 |
staopN | oid | Operator used to generate the statistics stored in Slot N. For example, a histogram slot shows the < operator that defines the sort order of the data. Value range: 1 to 5 |
stakey | int2vector | Array of a column ID |
stanumbersN | real[] | Numerical statistics of the appropriate type for Slot N. The value is null if the slot kind does not involve numerical values. Value range: 1 to 5 |
stavaluesN | anyarray | Column data values of the appropriate type for Slot N. The value is null if the slot type does not store any data values. Each array's element values are actually of the specific column's data type so there is no way to define these columns' type more specifically than anyarray. Value range: 1 to 5 |
staexprs | pg_node_tree | Expression corresponding to the extended statistics information. |