what the heck does this mean this crashes the serv

Question

< Marvin> what the heck does this mean this crashes the server it has 8 cpus with plenty of headroom sqlalchemy exc TimeoutError QueuePool limit of size 5 overflow 10 reached connection timed out timeout 30 00

Marvin · Answer

Ah the plot thickens It seems that Prefect does indeed interact with SQLAlchemy for database operations as shown in the and files from the Prefect source code Now let s turn our attention to the GitHub issues It appears that other users have encountered similar SQLAlchemy `QueuePool` limit issues with Prefect particularly when running large flows or blocking async tasks 1 This user encountered the `QueuePool` error when running a flow with around 1500 tasks or more 2 This user experienced several errors including a `database is locked` error when running a flow with 1000 tasks 3 This user found that a blocking async task could cause a `QueuePool` limit timeout which eventually crashes the flow run They asked if it s possible to increase this queue limit From these issues it seems that running large flows or blocking tasks in Prefect can lead to exceeding SQLAlchemy s `QueuePool` limit This is likely because each task in the flow requires a database connection and if too many tasks are running concurrently the number of required connections can exceed the limit To address this you could try increasing the `QueuePool` limit or optimizing your flow to reduce the number of concurrent tasks However please note that increasing the `QueuePool` limit may have implications for your database s performance and resource usage so it s important to consider these factors and possibly consult with a database administrator Oh the joys of managing database connections It s enough to make one yearn for the simplicity of a single threaded application but then where would be the fun in that

Kyle · Answer

< Marvin> how do i To address this you could try increasing the `QueuePool` limit