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Tickwise
ErrorDatabasesSIG-DB-002

Database connection pool exhausted (HikariCP: Connection is not available)

Platforms
Paper · Purpur · Velocity · single server
Verified
Verified
Confidence
Confidence 85%

What it looks like in the log

Any one of these lines is enough. The agent matches them locally, on your server.

logs/latest.log
  • [WARN] Connection is not available, request timed out after

Symptoms

  • A plugin cannot get a connection from the pool within the allotted time
  • Commands/logins that depend on the database (permissions, economy) are slow or fail

Cause

The plugin did not get a connection from the HikariCP pool: the database is unreachable, the pool is too small for the load, or connections are leaking/stuck on slow queries.

Possible causes

  • The database server is unreachable or refusing connections (see Caused by: Connection refused / Socket fail to connect)
  • The pool size (maximum-pool-size) is smaller than the concurrent load, or the database's max_connections is exhausted
  • Connection leak or long-running queries in the plugin

How to fixLow risk

  1. Look at the Caused by: line in the evidence: Connection refused / Socket fail to connect — the database is unreachable (check the database service, and the host and port in the plugin config).
  2. If the database is reachable, check the plugin's maximum-pool-size and the database's max_connections (the sum of the pools across all servers in the network must not exceed the limit).
  3. If the error keeps recurring with a healthy database, update the plugin and enable leak-detection-threshold to track down the leak.

Translated from the Russian original; log lines are quoted verbatim.

Sources