Behavior of connection.Isvalid() on a multithreaded connection

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Title	Behavior of connection.Isvalid() on a multithreaded connection

URL Name	Behavior-of-connection-Isvalid-on-a-multithreaded-connection

Article Number	000184513

Environment	Product: Connect for JDBC Version: All supported versions OS: Java Database: All supported databases Application: All supported application

Question/Problem Description

In a multithreaded application, the first thread executes a statement that takes 1 minute. Second thread executes connection.isvalid(5), which should return in 5 seconds. Instead, the isValid() call waits for the statement on the other thread to return.

Steps to Reproduce

Clarifying Information

From the JDBC Specification:

isValid
boolean isValid(int timeout)
throws SQLException

Returns true if the connection has not been closed and is still valid. The driver shall submit a query on the connection or use some other mechanism that positively verifies the connection is still valid when this method is called.

The query submitted by the driver to validate the connection shall be executed in the context of the current transaction.

Parameters:
timeout - - The time in seconds to wait for the database operation used to validate the connection to complete. If the timeout period expires before the operation completes, this method returns false. A value of 0 indicates a timeout is not applied to the database operation.

Returns:
true if the connection is valid, false otherwise

https://docs.oracle.com/javase/7/docs/api/java/sql/Connection.html#isValid(int)

Error Message

Defect Number

Enhancement Number

Cause

This is expected behavior. Since the driver needs to submit a query to the server in order to determine whether the connection is valid or not, if the connection is busy executing or processing results for a statement, then isValid is not going to gain access to the connection until all the processing of that statement is complete. Once the connection becomes available for isValid to execute its database operation, then the timer starts for the timeout value as is described by the specification.

Resolution

When isValid() is called, the driver submits a query on the connection to verify that the connection is still valid. If a connection is in use, then the driver's isValid method will wait for the connection to become available before proceeding to assess the connection's state.

Workaround

Notes

Last Modified Date	7/13/2016 8:51 AM

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Behavior of connection.Isvalid() on a multithreaded connection

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