7.3.6 The rpd_preload_stats Table

The rpd_preload_stats table stores column level statistics collected from InnoDB tables. The statistics are used to estimate the number of HeatWave nodes required for a given dataset before loading the tables into the HeatWave Cluster.

The rpd_preload_stats table has these columns:

• TABLE_SCHEMA

  The schema name.

• TABLE_NAME

  The table name.

• COLUMN_NAME

  The column name.

• AVG_BYTE_WIDTH_INC_NULL

  The average byte width of the column. The average value includes NULL values.

The rpd_preload_stats table has the following characteristics:

• It is read-only. DDL, including TRUNCATE TABLE, is not permitted.

• It is truncated before new statistics are added.

• It cannot be dropped, truncated, or modified by DML statements directly.

• Statistics are not persisted when the server is shut down.

• It has a limit of 65536 rows.

• Statistics are approximate, based on an adaptive sample scan.

• Statistics are deterministic, provided that the data does not change.