Memory Leak When Using Oracle UCP With CLOBs (Doc ID 3075740.1)

Last updated on MARCH 12, 2025

Applies to:

Symptoms

On : 23.5 version, Thin JDBC driver

ACTUAL BEHAVIOR
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When using Oracle Universal Connection Pool (UCP) with the Thin JDBC driver version 23.5 and fetching large result sets containing CLOBs, the application experiences significant memory leaks. The memory usage increases dramatically during operations involving UCP connections, eventually leading to an out-of-memory condition in long-running server applications. In comparison, connections created using DriverManager do not exhibit this memory leak.

EXPECTED BEHAVIOR
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Memory usage should remain stable when using UCP connections, similar to the behavior observed with DriverManager connections. Fetching large result sets containing CLOBs should not result in excessive memory consumption or memory leaks.

Cause

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