HOLOGRES_STATISTIC.HG_STATS_MISSING lists tables in the current database that are missing statistics. Query this view to identify which tables need ANALYZE, then run ANALYZE selectively to improve query performance.
Tables without up-to-date statistics cause the query optimizer to generate poor execution plans, such as an incorrect join order that results in large-table shuffles, slow queries, or out-of-memory (OOM) errors.
Prerequisites
Before you begin, ensure that you have:
A Hologres instance running V2.2.15 or later
SCHEMA USAGE or higher permission on the schemas you want to inspect
Fields
The following table describes the fields in HOLOGRES_STATISTIC.HG_STATS_MISSING.
| Field | Data type | Description |
|---|---|---|
schemaname | TEXT | Schema name |
tablename | TEXT | Table name |
nattrs | INTEGER | Number of columns |
tablekind | TEXT | Table type (for example, internal table, foreign table) |
fdwname | TEXT | Foreign data wrapper (FDW) name. Populated for foreign tables only |
autovacuum_enabled | TEXT | Whether Auto Analyze is enabled for the table. Available in V3.1 and later |
reason | TEXT | Reason why statistics are missing. Use this field to determine the next action. Available in V3.1 and later |
The view includes non-partitioned tables, partitioned tables, foreign tables, and materialized views. Other table types are excluded and are not counted in the Number of tables missing DB statistics monitoring metric.
Find and fix tables with missing statistics
Step 1: Check the monitoring metric
To see which databases have tables missing statistics, open the Hologres Management Console. In the left navigation pane, click Instances. On the product page of your target instance, in the left navigation pane, click Monitoring Information to view the Number of tables missing DB statistics metric.
Step 2: Query the view
Run the following query in the target database to list all tables with missing statistics.
SELECT * FROM hologres_statistic.hg_stats_missing;Example output:
schemaname | tablename | nattrs | tablekind | fdwname
------------+-------------------+--------+-------------------+---------
public | spatialxxxxx | 5 | table |
public | smtxxx | 4 | foreign table | oss_fdw
public | smtxxxxx | 4 | foreign table | oss_fdw
public | view_xxxxxx | 14 | materialized view |
(4 rows)On V3.1 and later, check the reason field to understand why each table is missing statistics, and the autovacuum_enabled field to see whether Auto Analyze is configured for it.
Step 3: Run ANALYZE
Run ANALYZE on the tables that need statistics. The following example analyzes a single table.
ANALYZE spatialxxxxx;Repeat for each table returned by the view.
Step 4: Verify the result
Return to Monitoring Information in the Hologres Management Console. The Number of tables missing DB statistics metric should decrease.
