Recommended practice on configuration for Qlik Sense

[Yoichi_Hirotake]

This article provides a list of the best practices for Qlik Sense configuration. It is worth implementing each item, especially for a large environment so that your database can handle the volume of requests coming from all its connected nodes. 

Max Connections

For basic information, see Max Connections.

Specifies the maximum number of concurrent connections (max_connections) to the database. The default value for a single server is 100.

In a multi-node environment, this should be adjusted to the sum of all repository connection pools + 20. By default, this value is 110 per node. 

Assuming two nodes and assuming the default value of 110 per node, the value would be 240.

1. Stop all of the Qlik Sense services
2. Open C:\ProgramData\Qlik\Sense\Repository\PostgreSQL\X.X\postgresql.conf
3. Set max_connections = 110
4. Save the file
5. Restart all of the Qlik Sense Services

How to determine the Database Max Pool

The value of 110 above is a default example. You can further refine the value.

The connection pool for the Qlik Sense Repository is always based on core count on the machine. To date, our advise is to take the core count of your machine and multiply it by five. This will be your max connection pool for the Repository Service for that node.

This should be a factor of CPU cores multiplied by five.

If 90 is higher than that result, leave 90 in place. Never decrease it.

For more information about Database Max Pool Size Connection, see https://wiki.postgresql.org/wiki/Number_Of_Database_Connections

Related Content:

Optimizing Performance for Qlik Sense Enterprise  
PostgreSQL: postgresql.conf and pg_hba.conf explained  
Database connection max pool reached in Qlik Sense Enterprise on Windows 

[Filippo_Nicolussi_P]

To be aligned with the Qlik Sense Version we suggest to check on help. 

For example here  Installing Qlik Sense in a multi-node site ‒ Qlik Sense for administrators   for Qlik Sense May 2021 count seems 110 per node + 20 . 

[mbespartochnyy]

Does anyone know what is the definition of "connection" in this context?

Is it number of some users? Number of servers? Number of requests?

If I see that there are 5 "connections" at the moment. What exactly is it count of?

[Sonja_Bauernfeind]

Hello @mbespartochnyy 

The number of connections refers to database connections as defined by PostgreSQL. For more information about Database Max Pool Size Connection, see https://wiki.postgresql.org/wiki/Number_Of_Database_Connections

It is not directly related to your active Qlik users or their requests. 

All the best,
Sonja 

[diagonjope]

Hi @Sonja_Bauernfeind 

Why is the number of max_connections so high?  Given that there 3-6 Qlik Sense services per node, and, presumably, the connections with the Repository Database are established through the Qlik Repository Service in each node, I have difficulties understanding why this number should be so high.  According to this Digital Ocean post, each active connection uses about 10 MB of RAM, so Increasing this parameter value by 110 per cluster node might increase RAM consumption significantly in the node running the repository database.

Please advise.

Cheers,

++José

[Sonja_Bauernfeind]

Hello @diagonjope 

This would be a question best asked in the Qlik Scalability group. I've also reached out to our subject matter experts to see if I can get you more information directly, but I highly recommend posting in the correct group.

All the best,
Sonja 

[Sonja_Bauernfeind]

Hello again @diagonjope 

In addition to the Scalability group, we recommend reviewing Optimizing Performance for Qlik Sense Enterprise which goes into more detail on this topic.

All the best,
Sonja