SAP HANA : Adjust the data retention time of Embedded Statistics Server tables
With the embedded statistics server the retention time for most of the histories is already 42 days.
Nevertheless there are still a few histories with a rather small default retention time. Check ID 750 ("Stat. server tables with retention < 42 days") of SQL: "HANA_Configuration_MiniChecks" (SAP Note 1969700) reports tables where the retention time may be increased to 42 days, however there are no .ini configuration parameters as such to adjust this.
To see all the statistic server tables, associated IDs, and current retention value execute the mini check SQL "HANA_StatisticsServer_Histories_RetentionTime" which can be found in the collection of SQL statements attached to SAP Note 1969700 - SQL Statement Collection for SAP HANA.
Then you can adjust the retention time with the following command:
UPDATE _SYS_STATISTICS.STATISTICS_SCHEDULE SET RETENTION_DAYS_CURRENT=42 WHERE ID=5006;
In this example we are setting the retention of the HOST_HEAP_ALLOCATORS table (id 5006) to 42 days.
Experience has shown that a retention time of 6 weeks (42 days) is a good compromise between size and analysis capabilities. Having 6 weeks of history available it is always possible to compare current issues with a time of the same load one month back (e.g. month's end closing).
Note : The standalone statistics server mainly used a retention time of 30 days. Rather than adjusting the retention time, it is recommended to switch to the Embedded Statistics Server (ESS).