52.53. pg_statistic_ext_data

52.53. `pg_statistic_ext_data`
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## 52.53. `pg_statistic_ext_data` #

The catalog `pg_statistic_ext_data` holds data for extended planner statistics defined in `pg_statistic_ext`. Each row in this catalog corresponds to a statistics object created with `CREATE STATISTICS`.

Normally there is one entry, with `stxdinherit` = `false`, for each statistics object that has been analyzed. If the table has inheritance children or partitions, a second entry with `stxdinherit` = `true` is also created. This row represents the statistics object over the inheritance tree, i.e., statistics for the data you'd see with `SELECT * FROM `table`*`, whereas the `stxdinherit` = `false` row represents the results of `SELECT * FROM ONLY `table``.

Like `pg_statistic`, `pg_statistic_ext_data` should not be readable by the public, since the contents might be considered sensitive. (Example: most common combinations of values in columns might be quite interesting.) `pg_stats_ext` is a publicly readable view on `pg_statistic_ext_data` (after joining with `pg_statistic_ext`) that only exposes information about tables the current user owns.

Table 52.53. `pg_statistic_ext_data` Columns

Column Type Description
`stxoid` `oid` (references `pg_statistic_ext`.`oid`) Extended statistics object containing the definition for this data
`stxdinherit` `bool` If true, the stats include values from child tables, not just the values in the specified relation
`stxdndistinct` `pg_ndistinct` N-distinct counts, serialized as `pg_ndistinct` type
`stxddependencies` `pg_dependencies` Functional dependency statistics, serialized as `pg_dependencies` type
`stxdmcv` `pg_mcv_list` MCV (most-common values) list statistics, serialized as `pg_mcv_list` type
`stxdexpr` `pg_statistic[]` Per-expression statistics, serialized as an array of `pg_statistic` type

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