Top 3 alerts in HANA databases:
ALERT_ID ALERT_NAME
58 Plan cache size
0 Internal statistics server problem
3 Inactive services
My favorite is the alert 58. SAP simply cannot provide a good default size for the HANA plan cache. So every HANA DBA has to initially adapt the plan cache and reevaluate the size in case of alert 58.
The optimal size depends on your workload, you don't want to waste memory but you also don't want to impede performance either. The SAP note 1977253 clarifies all questions, for ABAP systems I calculate the recommended plan cache size directly via SQL:
select max(connections)*15*1024*1024 from (select snapshot_id,count(distinct connection_id) connections from _sys_statistics.host_connections group by snapshot_id)
For alert 0 there is no check threshold, I believe this is an error which is raised automatically once the statistics server detects some issues. Also the severity level 5 makes this alert unique. Anyway, here you'll have to dive into the trace files and search for a suitable SAP note to fix this.
The situation for alert 3 is quite similar. "Inactive services" is a very sensitive alert which is probably already known to you. Again, there is no panacea since it is just a symptom for different kind of issues.
ALERT_ID ALERT_NAME
58 Plan cache size
0 Internal statistics server problem
3 Inactive services
My favorite is the alert 58. SAP simply cannot provide a good default size for the HANA plan cache. So every HANA DBA has to initially adapt the plan cache and reevaluate the size in case of alert 58.
The optimal size depends on your workload, you don't want to waste memory but you also don't want to impede performance either. The SAP note 1977253 clarifies all questions, for ABAP systems I calculate the recommended plan cache size directly via SQL:
select max(connections)*15*1024*1024 from (select snapshot_id,count(distinct connection_id) connections from _sys_statistics.host_connections group by snapshot_id)
For alert 0 there is no check threshold, I believe this is an error which is raised automatically once the statistics server detects some issues. Also the severity level 5 makes this alert unique. Anyway, here you'll have to dive into the trace files and search for a suitable SAP note to fix this.
The situation for alert 3 is quite similar. "Inactive services" is a very sensitive alert which is probably already known to you. Again, there is no panacea since it is just a symptom for different kind of issues.
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