Add maximumPendingConnections property for load-shedding#2387
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vlsi wants to merge 1 commit intobrettwooldridge:devfrom
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Add maximumPendingConnections property for load-shedding#2387vlsi wants to merge 1 commit intobrettwooldridge:devfrom
vlsi wants to merge 1 commit intobrettwooldridge:devfrom
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Under traffic spikes or database outages, threads can accumulate unboundedly waiting for pool connections, then fail in a thundering herd after connectionTimeout. This adds an opt-in admission control that rejects getConnection() calls immediately when too many threads are already waiting, preventing waiter buildup and reducing the blast radius of pool exhaustion. The property defaults to 0 (unlimited) for full backward compatibility. Refs: brettwooldridge#580 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Feb 14, 2026
| super(config); | ||
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| this.connectionBag = new ConcurrentBag<>(this); | ||
| this.connectionBag = new ConcurrentBag<>(this, config.getMaximumPendingConnections()); |
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The drawback of passing getMaximumPendingConnections is that ConcurrentBag won't react to the changes of maximumPendingConnections.
An alternative options could be:
a) Pass HikariConfig to ConcurrentBag
b) Add interface ConcurrentBagConfig { int getMaximumWaiters(); int getMaximumObjects();} so the bag could query the required limits
Any thoughts?
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Under traffic spikes or database outages, threads can accumulate unboundedly waiting for pool connections, then fail in a thundering herd after
connectionTimeout. This adds an opt-in admission control that rejectsgetConnection()calls immediately when too many threads are already waiting, preventing waiter buildup and reducing the blast radius of pool exhaustion.The property defaults to 0 (unlimited) for full backward compatibility.
Fixes #580