Amazon Redshift - Table Statistics

Imported Statistics

info

Statistics are imported when the Import row count and statistics option is selected for the metadata import task.

Statistics	Is imported	Description
Row count		Indicates the number of rows in table
Last user query		Time of last user SELECT operation on table
Number of user queries		Number of user SELECT operation on table
Last user update		Time of last user INSERT, UPDATE and DELETE operations on table
Number of user updates		Sum of user INSERT, UPDATE and DELETE operations on table
Last load time		Time of last user COPY command on table

Requirements

Dataedo requires access to the following tables and views:

Object	Used for
pg_class	Row count
pg_namespace	Schema resolution for row count
SYS_QUERY_HISTORY	Query type and status behind the query and update counters
SYS_QUERY_DETAIL	Per-table query timestamps
SVV_TABLE_INFO	Mapping query history to table names

Row count comes from the catalog and works for any user with USAGE on the schema. Everything else does not:

• Amazon Redshift documents that SVV_TABLE_INFO is "visible only to superusers".
• SYS_QUERY_HISTORY is "visible to all users. Superusers can see all rows; regular users can see only their own data."

A dedicated read-only Dataedo account therefore imports row count only. Query-based statistics need elevated privileges — the query and update counters, timestamps, and last load time stay empty until the account is a superuser or receives the access below:

ALTER USER dataedo_user SYSLOG ACCESS UNRESTRICTED;
GRANT SELECT ON SVV_TABLE_INFO TO dataedo_user;

Limitations

• Row count is only an estimate used by the planner. It is updated by VACUUM, ANALYZE, and a few DDL commands. If the table has never been vacuumed or analyzed, the row count is 0.
• SVV_TABLE_INFO returns no information for empty tables, so tables that have never held data get no query statistics.
• Amazon Redshift purges query history automatically. Activity older than the retention window of your cluster or workgroup is no longer reflected in the counters and timestamps.

Learn more

Read more about table statistics import in main article