fix(NODE-6589): background task does not prune idle connections when minPoolSize=0 #4569
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baileympearson
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Jun 27, 2025
This reverts commit b2c9675.
durran
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durran
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Jul 1, 2025
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Description
What is changing?
ConnectionPools now run the background thread to prune idle connections even when minPoolSize = 0.
Is there new documentation needed for these changes?
What is the motivation for this change?
Release Highlight
Idle Connections are now pruned during periods of no activity when minPoolSize=0
A MongoClient configured with a maxIdleTimeMS and minPoolSize of 0 is advantageous for workloads that have sustained periods of little or no activity because it allows the connection pool to close connections that are unused during these periods of inactivity. However, due to a bug in the ConnectionPool implementation, idle / perished connections were not cleaned up unless minPoolSize was non-zero.
With the changes in this PR, the ConnectionPool now always cleans up idle connections, regardless of minPoolSize.
Double check the following
npm run check:lintscripttype(NODE-xxxx)[!]: descriptionfeat(NODE-1234)!: rewriting everything in coffeescript