RFR: JDK-8277795: ldap connection timeout not honoured under contention [v3]

[Mark Sheppard]

On Tue, 14 Dec 2021 15:26:54 GMT, Rob McKenna <robm at openjdk.org> wrote:

>> This fix attemps to resolve an issue where threads can stack up on each other while waiting to get a connection from the ldap pool to an unreachable server. It does this by having each thread start a countdown prior to holding the pools' lock. (which has been changed to a ReentrantLock) Once the lock has been grabbed, the timeout is adjusted to take the waiting time into account and the process of getting a connection from the pool or creating a new one commences.
>> 
>> Note: this fix also changes the meaning of the connection pools initSize somewhat. In a situation where we have a large initSize and a small timeout the first thread could actually exhaust the timeout before creating all of its initial connections. Instead this fix simply creates a single connection per pool-connection-request. It continues to do so for subsequent requests regardless of whether an existing unused connection is available in the pool until initSize is exhausted. As such it may require a CSR.
>
> Rob McKenna has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Allow the test to pass on MacOSX

src/java.naming/share/classes/com/sun/jndi/ldap/LdapClientFactory.java line 70:

> 68:     public PooledConnection createPooledConnection(PoolCallback pcb, long timeout)
> 69:         throws NamingException {
> 70:         return new LdapClient(host, port, socketFactory,

any need to perform sanity check against erroneous negative values on the timeout supplied here and in other parts of the solution

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PR: https://git.openjdk.java.net/jdk/pull/6568