STATSCACHE System Table Description


A pseudo table generated to show statistics cached for use by the NuoDB query optimizer. Rows in SYSTEM.STATSCACHE represent either table or index objects in the database.

Caution: Client applications should never contain code that accesses SYSTEM pseudo tables as they are subject to, and furthermore likely to, change from release to release.


Field Type Description
ID bigint The database ID for the table or index object.
VERSION bigint Index statistics are versioned and this field represents the version number.
TYPE string Currently this is either index or table.
NAME string The name of either the index or the table.
VALID boolean True if valid and usable by the query optimizer.
CARDINALITY bigint The cardinality of the index or table.
DISTINCTCOUNT bigint The number of distinct keys in the index, null for tables.
AVERAGEKEYLENGTH double The average length of a key in the index, null for tables.
HISTOGRAMCOUNT bigint The number of histogram buckets for the index, null for tables.
SPAN string The partitions that are spanned by the statistics. Where tables are not partitioned, or where statistics span all partitions, this column does not populate.