Connection mechanism workprocesses in HANA

[Former Member]

Just curious to know if there is anything on HANA server that controls how many work processes it can accomodate. For instance, in oracle there are processes at DB level and you need sufficient processes here to increase work processes in SAP. Checking if there is something similar and if not, what controls how many work processes can connect to HANA Server. I ask this because i ran a query m_transactions on active user transactions and the results doesn't tally. There are fewer processes from query on HANA than the total number of work processes. Also does active here mean work process have connected and have active session ?

Another note, does commit work on the same session in which work process is running or does it behave differently. I am asking because our commits are taking time and we see sql's like commit on connection 0 and 1 most of the times so wondering if work processes that commit run on a specific connection thats exclusive to commit.

Regards

Kalyan

[lbreddemann]

The number of connections that are allowed to the database is usually not effectively limited (I believe the default limit is currently around 64K).

Since sessions are not actively doing anything most of the time (seen from the indexserver perspective) there can be many more sessions connected to the system at the same time than there are worker threads.

As SAP HANA really is a single-process-many-threads design, the connection/session handling is very much closer to e.g. Oracle's SHARED SERVER approach than to what is usually done with NetWeaver on Oracle (1:1 relation workprocess to "shadow"-process on db level).

When you're talking about COMMIT you have to distinguish between the ABAP command COMMIT WORK (or an implicit COMMIT WORK) and the DB command COMMMIT.

On all DBMS platforms those work very differently and the SAP NetWeaver Updater process decouples these two concepts.

That's not specific to SAP HANA though.

- Lars