Nope, you got me, I have not clue why that would happen.

My setup also uses pconnect and I cannot get it to open more than 7 connections.

(atleast, without using more than one simultaneous browser session)

    a month later

    Question for you, are you using netscape?
    I found that refreshing a page under netscape causes lots of connections to show up under mysql's SHOW PROCESSLIST, however under IE, only 1 is created.

    I'm investigating further, let me know if you find anything.

    Andrew

      Hmmm, quite interesting. I am using netscape 4.75. I've just tried it out with netscape 6 beta. The difference is 5 persistant connections generated by 4.75 and only 2 by ver 6 beta.

      Lars Brandi Jensen

        Did some more testing, seems like most everything makes more connections, tried apache's benchmarking tool, lynx etc. Could it be IE's KeepAlive HTTP? Another thing, is that the connections eventually get reused after there are about 7 or 8. Very odd indeed.

        Andrew

          2 months later

          I think is happening because the web server has a number of child processes that take http requests, usually between 5-10 children on a low-use apache engine like the one we probably all develop on.

          Any one of these children can take a php request, and when pconnect is called from your script, the php engine only opens and keeps the connection open for that child.

          So if on a subsequent request you get served by a different child of apache, that child will not have a connection yet.

          Then, when all children have had a chance to service a request, and have opened a connection, you'll start to see frequent re-use.

          Your comments about IE's KeepAlive are probably accurate, by keeping the same HTTP connection open, the same apache child is being used, which has already opened up its database connection.

            a month later

            So to fix it I should change the KeepAlive variable? and set it to what?

            KeepAlive is not set to 30.000 (or above) and this is the value I can see in mysql processlist...

            so what should I do.. how to tell mysql or apache "hey you guys, dont keep such old processes - kill all if they reached, lets say, 5000"....

            btw: does 5000 means 5000 seconds?

              a month later

              My connection are not even reuse, I often have 200 process all in sleep mode? What can I do the de process to reuse themself? thanks

                Generally, pconnect saves your processor time, while connect saves your memory. Choose what is more appropriate for you.

                And now the most important thing, I have a server with a quite high load so sometimes, I got this message - "could not connect to mysql server..." - maximum connections limit was reached, but I had a lot of threads with timeout over 30.000 - quite to much... and I was looking for some answer here and on some other resources in interenet, but could find anything.

                Well good news for everyone with the same problem, as old proverb says: RTFM šŸ™‚

                In mysql manual is written anything, you ever would like to know...

                The parameter to adjust the threads timeout is "wait_timeout" - by default set to 28.000.

                Now, to set this value you could to it in two ways: one is, to put in your /etc/my.cnf (of wherever your mysql config file is) or via command line with --set-variable wait_timeout=value (--set-variable var=option)

                  2 months later

                  so for VERY high load sites... connect or pconnect? that is my question.

                    • [deleted]

                    • Post #16

                    pconnect and lots and lots of memory.

                      a year later

                      I run a website that receives around 10k unique users a day, often up to 300-400 users on at a time. We have been having problems with too many connections for mySQL lately and we have 1 gig of ram.

                      I'll try switching pconnect to connect and let you guys know how it works.

                        20 days later

                        Yeah, I have a site that has about 25,000 unique visitors a day, and we recently ran into this same problem. We have 4 webservers talking to one dual processor MySQL server with 500 MB of RAM. We were using pconnect until this last week when we were reaching our max_connections of 250, 350, and then 450. We couldn't bump it up anymore because our MySQL server started swapping at 450 connections.

                        Since then, we have switched to regular mysql_connect and all machines are now happy. Our MySQL server is sleeping again, but our webservers our doing a little more work. Also, I have seen no visual difference in page load time.

                        From my research and experience, I would suggest only using mysql_pconnect if you have tons of RAM on the DB server (1+ GšŸ˜Ž and you can tweak the wait_timeout variable in MySQL to something manageable. The default is 8 hours, which was way too long in our situation.

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