Frequently Asked Question

When running reports , there is generally 2 seperate connections that need to be used (assuming the report data is returned from a single data source).
1 connection is made to the Yellowfin DB to get the report definitions, check user access etc..
1 connection is also made to the data source to actually retrieve the data

By default the connection settings for both the YF DB and data source are :




Min Connections: Number of connections that are opened upon startup
Max Connections: Number of max connections allowed. If a 6th connection is made, it will wait until one is free.
Refresh Time: This simply refreshes all connections (this helps make sure none of the connections are corrupted or become stale)
Use secondary pool: Can be used to run ONLY Yellowfin background tasks (e.g. Broadcasts, Caching views/filters). If enabled this gives you the same parameters as above.

So how does Yellowfin decide to open or close a connection ?
When Yellowfin starts, 1 connection is made to the YF DB and 1 to each datasource.
When a user opens a report, the connections opened during startup are used, the user then closes the report. If a 2nd user then logs in and opens the same report, the same connection is used.
However if 2 users try to run 2 reports at the same time another connection must be opened;
-If they are running reports from different data sources, then 2 connections will be used for the Yellowfin DB and 1 connection will each be used for the data sources.
-If they are running reports from the same data source, 2 connections will be used for the Yellowfin DB and 2 connections will be used for the data source

As you can see extra connections are only opened if none are free, so unless you have multiple users running reports at the same time there is usually no need to increase the Max Connecitons.
Though if you have reports that take a long time to run you may need to consider this, as the connection to the data source will be used until the report is loaded.

Related posts:

How to increase the number of Max connections for the Yellowfin repository DB

How to increase the number of Max connections for a data source