SAP HANA - Statistics service (Alert|ESS)
About
The SAP HANA statistics server (or: statistics service) is a central tool for monitoring the SAP HANA database.
Among others it performs the following tasks:
- Regular check for critical situations and generation of alerts
- Regular history collection of monitoring information into histories located in the _SYS_STATISTICS schema.
The embedded statistics server (ESS) consists of two components.
- A scheduler
- and workers
| Component run on | Standalone | Multi-tenant configuration |
|---|---|---|
| scheduler | indexserver | nameserver |
| workers | indexserver | indexserver |
On SYSTEMDB for Multi-tenant configuration:
The internal monitoring infrastructure of the SAP HANA database (statistics service) is continuously collecting and evaluating information about status, performance, and resource usage from all components of the SAP HANA database.
This information is historicized to tables and views in the schema _SYS_STATISTICS. You can use these tables and views to analyze system behavior over time.
Articles Related
Architecture
The embedded statistics service (ESS) uses Triggers to execute procedures which are collecting statistics of system-states. Those procedures are executed by the index server.
The collected data are stored in tables, views… in the _SYS_STATISTICS folder. The statistic service is a totally separate service that does not affect any other functionality or components of the system except system statistics.
Starting with revision 94, the statistics server has been disabled and integrated into the index server.
Management
Monitoring - Studio
Administration > Alert
Reinstall
Steps to re-install the embedded statistics service (ESS):
- Disable the embedded statistics service with:
alter system alter configuration ('nameserver.ini','SYSTEM') set ('statisticsserver','active')='false' with reconfigure;
- Connect HANA-Studio to the database.
- Expand all folder and sub-folder of the _SYS_STATISTICS schema.
- Delete all tables, views, … in the _SYS_STATISTICS schema (except the Triggers. You can't delete them, because there is a security mechanism that you could not delete objects where the name starts with “_SYS”).
- If all folders in the _SYS_STATISTICS schema are empty (except for the “Triggers” folder), then start the installation of the embedded statistics service (ESS) with that will also re-create all formerly deleted objects:
alter system alter configuration ('nameserver.ini','SYSTEM') set ('statisticsserver','active')='true' with reconfigure;