What is the significance of running multiple index servers on single tenant database

[prabhjotsingh]

I'm running a 3 node scaleout environment. I have only one tenant database in HANA2.0SPS5 and i see 3 indexserver services running under my single tenant database. Is there any significance or it is waste of ports and SYSTEM resources.
Your reply is appreciated.

[dvankempen]

Got the answer to your question? To improve the knowledge base and make the right answers easier to find, please mark the best answer and close the question. Thanks!

Don’t know how? See https://answers.sap.com/questions/13162472/how-to-mark-an-answer-and-how-to-close-a-question.html

For the readers, before you leave, don't forget to up/down vote the answers. You can vote on the question too.

Thanks.

[dvankempen · Accepted solution]

Hi Prabhjot,

When all three indexservers services are hosted by host 1, the configuration could use a bit of tuning.

When are three indexserver services are running on a single host each, the setup is perfect.

Running multiple indexserver services on a single host is only supported for transition phases, e.g. if you recover a scale-out native SAP HANA backup onto a single host. When done, the additional indexserver services need to be removed.

As documented,

• Scale-Out Architecture of Tenant Databases

[prabhjotsingh · Accepted solution]

Does it make sense to have 3 index services running on tenant database DB2 on HOST1

hdbsql SYSTEMDB=> \c -d HDB
Connected to HDB@scaleout0.dell.co:30013
hdbsql HDB=> select * from M_SERVICES; | HOST | PORT | SERVICE_NAME | PROCESS_ID | DETAIL | ACT | SQL_PORT | COORDI | IS_DA | | ------------------- | ----------- | ------------- | ----------- | ------ | --- | ----------- | ------ | ----- |

| scaleout0.dell.co | 30000 | daemon | 6065 | | YES | 0 | NONE | FALSE |

| scaleout0.dell.co | 30001 | nameserver | 6287 | master | YES | 0 | MASTER | FALSE |

| scaleout0.dell.co | 30002 | preprocessor | 6594 | | YES | 0 | NONE | FALSE |

| scaleout0.dell.co | 30006 | webdispatcher | 7451 | | YES | 0 | NONE | FALSE |

| scaleout0.dell.co | 30010 | compileserver | 6591 | | YES | 0 | NONE | FALSE |

| scaleout0.dell.co | 30003 | indexserver | 6639 | master | YES | 30015 | MASTER | TRUE |

| scaleout0.dell.co | 30004 | scriptserver | 6645 | master | YES | 30034 | MASTER | TRUE |

| scaleout0.dell.co | 30007 | xsengine | 6648 | | YES | 0 | NONE | TRUE |

| scaleout0.dell.co | 30040 | indexserver | 6642 | | YES | 30041 | SLAVE | TRUE |

| scaleout0.dell.co | 30043 | indexserver | 7811 | | YES | 30044 | SLAVE | TRUE |

10 rows selected (overall time 16.936 msec; server time 863 usec)

[dvankempen · Accepted solution]

Updated the answer. Not supported (besides exceptional and temporary use cases)

[prabhjotsingh · Accepted solution]

How is indexserver partitioning helpful when done on the same host.

[dvankempen · Accepted solution]

You can partition tables, not indexservers. To partition, a single indexserver service suffices, i.e. different concepts: related but a requirement.