Oci_close does not release the connection when using DRCP

Question

Hello everyone,
we are currently testing the deplyment of DRCP with 11g. I have the whole thing setup (correctly to my best knowledge), but I am facing an issue. The call to oci_close does not seem to release the connection to the pool as I would expect and therefore we see similar behavior like we were getting without using the DRCP.
Our setup is using two RAC instances running 11.1.0.6.0, I am using PHP 5.1.6 with PECL installed oci8 1.3.4. The DRCP pool is configured and started, each with 100 max servers.
When the webserver is idle it looks, well, idle.
SQL> SELECT INST_ID,NUM_BUSY_SERVERS FROM GV$CPOOL_STATS;
INST_ID NUM_BUSY_SERVERS
1 0
2 0
The script is as simple as it gets:
<?php
$c = oci_pconnect('scott','tiger','IWPPOOLED');
$s = oci_parse($c, 'select * from emp');
$r = oci_execute($s, OCI_DEFAULT);
oci_close($c);
sleep(30);
?>
What I would expect is that the script would connect to the pool, do the work for a tiny moment and then release the connection for usage by other script.
But after I point the browser to the script, I get a 30 second loading time (as expected) but the server is busy all the time, like this:
SQL> SELECT INST_ID,NUM_BUSY_SERVERS FROM GV$CPOOL_STATS;
INST_ID NUM_BUSY_SERVERS
1 0
2 1
After the 30 second sleep, it is released and busy servers are back to 0.
If I load the server with ab using 256 connections:
ab -n 1000000 -c 256 -k http://mywebserver/ocitest.php
the pool is maxed out and the connects are stalling:
SQL> SELECT INST_ID,NUM_BUSY_SERVERS FROM GV$CPOOL_STATS;
INST_ID NUM_BUSY_SERVERS
1 95
2 95
My network config for this service is following:
IWPPOOLED =
(DESCRIPTION =
(LOAD_BALANCE=ON)
(FAILOVER=ON)
(ADDRESS = (PROTOCOL = tcp)(HOST = 10.1.16.33)(PORT = 1521))
(ADDRESS = (PROTOCOL = tcp)(HOST = 10.1.16.34)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = IWP)
(SERVER=POOLED)
(FAILOVER_MODE=
(TYPE=SELECT)
(METHOD=BASIC)
(RETRIES=5)
(DELAY=3)
The phpinfo() look like this:
OCI8 Support enabled
Version 1.3.4
Revision $Revision: 1.269.2.16.2.38.2.20 $
Active Persistent Connections 1
Active Connections 1
Oracle Instant Client Version 11.1
Temporary Lob support enabled
Collections support enabled
Directive Local Value Master Value
oci8.connection_class IWPAPP IWPAPP
oci8.default_prefetch 100 100
oci8.events On On
oci8.max_persistent -1 -1
oci8.old_oci_close_semantics Off Off
oci8.persistent_timeout -1 -1
oci8.ping_interval -1 -1
oci8.privileged_connect Off Off
oci8.statement_cache_size 20 20
I am using the instant client for 11g
Any ideas?
Thanks!
Michal

Answer 1

Don't forget to use oci_free_statement($s); See "Closing Oracle Connections" in The Underground PHP and Oracle Manual. (I was just simplifying this example today for the next release of the manual).
You may also see the "dedicated optimization", where a pooled server in a non- maxed-out pool is retained (unless needed by another PHP process) under the assumption that the initial PHP process might become active again. See http://www.oracle.com/technology/tech/php/pdf/php-scalability-ha-twp.pdf
Feel free to email me offline (see my profile) if there are questions/data you don't want to post.
cj
Edited by: cj2 on Oct 16, 2008 8:12 AM