Intermittent Poor Performance Retrieving PL/SQL Object Types (Doc ID 1222553.1)

Symptoms

When using the JDBC Thin driver to invoke PL/SQL packages that return results as PL/SQL objects, intermittently the performance becomes very slow in load tests.

Some details from representative tests follow; the same behavior may manifest in other circumstances as well.

Sample load test details:
* 3 packages
* All packages are using PL/SQL objects
* When a 100-user test is run, performance is fine
* When running load test (run for periodic time) of 200-400 users, then a huge load/huge CPU usage is seen from any of the 3 packages

Details from another load test:
* Anonymous block running 100,000 times with a stored procedure with a PL/SQL object type
* This reproduces the problem

It's been observed that in these tests, the DBMS_PICKLER package runs occasionally, and seems to correlate with the spikes in bandwidth.

This reproduces across multiple target 10.2.0.3 databases.
This reproduces when using the 9.0.x, 9.2.x.x, and 10.2.x.x JDBC driver.

Changes

Cause

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