[support] Problem with Drupals built in cache

Jamie Holly hovercrafter at earthlink.net
Thu Jan 20 17:06:25 UTC 2011


You're using the regular memcache module. I've never used that one. 
Maybe someone who has would have an idea. Personally, I use cacherouter 
since it offers more features and flexibility.

Jamie Holly
http://www.intoxination.net
http://www.hollyit.net


On 1/20/2011 10:32 AM, Margusja wrote:
> In error log there is no problems recorded.
>
> tnx for link. I'll check it out. Maybe it helps me closer to resolve my
> problem.
>
> config lines from settings.php
>           $conf['cache_inc'] = './sites/all/modules/memcache/memcache.inc';
>           $conf['memcache_key_prefix'] = 'seb_default';
>
> Tervitades, Margus (Margusja) Roo
> +372 51 48 780
> http://margus.roo.ee
> msn: margusja at kodila.ee
> skype: margusja
>
>
> On 1/20/11 5:14 PM, Jamie Holly wrote:
> >  You got a lot of misses in there. Have you checked your error logs to
> >  see if anything is going on? One thing that is possible is that you are
> >  hitting the 1mb limit for objects in memcache with the variable cache.
> >  This thread has some details on it:
> >
> >  http://groups.drupal.org/node/116764
> >
> >  Also if you could post your memcache configuration from settings.php to
> >  see if anything is going on in there.
> >
> >  Jamie Holly
> >  http://www.intoxination.net
> >  http://www.hollyit.net
> >
> >
> >  On 1/20/2011 10:01 AM, Margusja wrote:
> >>  Tnx for hints.
> >>
> >>  I enabled memcache in my PHP conf. And I think the module is loaded.
> >>  [16:50:57 root at arendus ~]# php -i | grep memcache
> >>  memcache
> >>  memcache support =>    enabled
> >>  memcache.allow_failover =>    1 =>    1
> >>  memcache.chunk_size =>    32768 =>    32768
> >>  memcache.compress_threshold =>    20000 =>    20000
> >>  memcache.default_port =>    11211 =>    11211
> >>  memcache.hash_function =>    crc32 =>    crc32
> >>  memcache.hash_strategy =>    consistent =>    consistent
> >>  memcache.lock_timeout =>    15 =>    15
> >>  memcache.max_failover_attempts =>    20 =>    20
> >>  memcache.protocol =>    ascii =>    ascii
> >>  memcache.redundancy =>    1 =>    1
> >>  memcache.session_redundancy =>    2 =>    2
> >>  Registered save handlers =>    files user memcache
> >>
> >>  [16:49:22 root at arendus ~]# echo stats | nc localhost 11211
> >>  STAT pid 30211
> >>  STAT uptime 23950
> >>  STAT time 1295535057
> >>  STAT version 1.2.8
> >>  STAT pointer_size 32
> >>  STAT rusage_user 0.130980
> >>  STAT rusage_system 0.311952
> >>  STAT curr_items 473
> >>  STAT total_items 1763
> >>  STAT bytes 587316
> >>  STAT curr_connections 10
> >>  STAT total_connections 242
> >>  STAT connection_structures 15
> >>  STAT cmd_flush 0
> >>  STAT cmd_get 9007
> >>  STAT cmd_set 1763
> >>  STAT get_hits 1025
> >>  STAT get_misses 7982
> >>  STAT evictions 0
> >>  STAT bytes_read 11112904
> >>  STAT bytes_written 8412213
> >>  STAT limit_maxbytes 67108864
> >>  STAT threads 5
> >>  STAT accepting_conns 1
> >>  STAT listen_disabled_num 0
> >>  END
> >>
> >>  Still in mysqld log:
> >>  110120 16:53:15       4102 Connect    user at localhost on db
> >>                4102 Query       SET NAMES "utf8"
> >>                4102 Query       SELECT 1 FROM access WHERE type = 'host'
> >>  AND 'IP' LIKE mask AND status = 0 LIMIT 0, 1
> >>                4102 Query       INSERT INTO semaphore (name, value, expire)
> >>  VALUES ('variable_cache_regenerate',
> >>  '14419249754d384c5bd38895.47612777', 1295535225.8664)
> >>                4102 Query       SELECT * FROM variable
> >>                4102 Query       DELETE FROM semaphore WHERE name =
> >>  'variable_cache_regenerate' AND value = '14419249754d384c5bd38895.47612777'
> >>                4102 Query       SELECT name, filename, throttle FROM system
> >>  WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight
> >>  ASC, filename ASC
> >>                4102 Query       SELECT * FROM languages ORDER BY weight
> >>  ASC, name ASC
> >>                4102 Query       SELECT dst FROM url_alias LIMIT 0, 1
> >>
> >>
> >>
> >>  Tervitades, Margus (Margusja) Roo
> >>  +372 51 48 780
> >>  http://margus.roo.ee
> >>  msn: margusja at kodila.ee
> >>  skype: margusja
> >>
> >>
> >>  On 1/20/11 4:03 PM, Jamie Holly wrote:
> >>>    Then I would check phpinfo to make sure that the memcache extension is
> >>>    loading into PHP (you can do this from admin ->     reports ->     status and
> >>>    then clicking on your PHP version number).
> >>>
> >>>    If that's showing up ok, you can run a command from the terminal to make
> >>>    sure things are being written/read from memcache:
> >>>
> >>>    echo stats | nc {memcache address} {memcache port}
> >>>
> >>>    Your main things to look at are the hits, misses, bytes and connections.
> >>>
> >>>    There are also some versions of memcache + the PHP extension that don't
> >>>    work well together. This can be a hit and miss thing finding them. I
> >>>    know there was a combination in the CentOS repos a year or so ago that
> >>>    caused problems. Getting the latest version of the PHP extension and
> >>>    building it from source would fix that.
> >>>
> >>>    Jamie Holly
> >>>    http://www.intoxination.net
> >>>    http://www.hollyit.net
> >>>
> >>>
> >>>    On 1/20/2011 8:43 AM, Margusja wrote:
> >>>>    Thx for a replay. I checked again my memcache and I think it works fine.
> >>>>
> >>>>    [15:40:16 root at arendus ~]# telnet localhost 11211
> >>>>    Trying 127.0.0.1...
> >>>>    Connected to localhost.
> >>>>    Escape character is '^]'.
> >>>>    stats
> >>>>    STAT pid 30211
> >>>>    STAT uptime 19724
> >>>>    STAT time 1295530831
> >>>>    STAT version 1.2.8
> >>>>    STAT pointer_size 32
> >>>>    STAT rusage_user 0.094985
> >>>>    STAT rusage_system 0.230964
> >>>>    STAT curr_items 67
> >>>>    STAT total_items 1089
> >>>>    STAT bytes 168012
> >>>>    STAT curr_connections 11
> >>>>    STAT total_connections 188
> >>>>    STAT connection_structures 14
> >>>>    STAT cmd_flush 0
> >>>>    STAT cmd_get 6580
> >>>>    STAT cmd_set 1089
> >>>>    STAT get_hits 711
> >>>>    STAT get_misses 5869
> >>>>    STAT evictions 0
> >>>>    STAT bytes_read 9254362
> >>>>    STAT bytes_written 5742821
> >>>>    STAT limit_maxbytes 67108864
> >>>>    STAT threads 5
> >>>>    STAT accepting_conns 1
> >>>>    STAT listen_disabled_num 0
> >>>>    END
> >>>>
> >>>>    rows from settings.php
> >>>>    if(extension_loaded('memcache')){
> >>>>               $conf['cache_inc'] = './sites/all/modules/memcache/memcache.inc';
> >>>>               $conf['memcache_key_prefix'] = 'xxx';
> >>>>    }
> >>>>
> >>>>    Tervitades, Margus (Margusja) Roo
> >>>>    +372 51 48 780
> >>>>    http://margus.roo.ee
> >>>>    msn: margusja at kodila.ee
> >>>>    skype: margusja
> >>>>
> >>>>
> >>>>    On 1/20/11 2:45 PM, Jamie Holly wrote:
> >>>>>      Drupal is still going to check the access table to see if you have any
> >>>>>      blocks in there for the current user, even if the table is empty.
> >>>>>
> >>>>>      The semaphore you are seeing is to prevent a cache stampede. You said
> >>>>>      that once you disabled memcache, everything worked fine. It looks like
> >>>>>      you have a problem with either your memcache server, the PHP memcache
> >>>>>      extension or your settings in Drupal for memcache. I would check the
> >>>>>      server first, since that's the easier. You can just do a telnet to check
> >>>>>      that out. From shell:
> >>>>>
> >>>>>      telnet (server address) (server port)
> >>>>>
> >>>>>      See if it connects OK.
> >>>>>
> >>>>>      As far as Pressflow+Memcache, yeah they work great together. I run that
> >>>>>      combination for a couple of clients, including one that has seen over
> >>>>>      150,000 page an hour, and never had a problem.
> >>>>>
> >>>>>      Jamie Holly
> >>>>>      http://www.intoxination.net
> >>>>>      http://www.hollyit.net
> >>>>>
> >>>>>
> >>>>>      On 1/20/2011 4:12 AM, Margusja wrote:
> >>>>>>      If I disable memcache support in PHP then in the problematic server I
> >>>>>>      see that there no problem anymore. So can memcache and pressflow cache
> >>>>>>      work parallel ?
> >>>>>>
> >>>>>>      Tervitades, Margus (Margusja) Roo
> >>>>>>      +372 51 48 780
> >>>>>>      http://margus.roo.ee
> >>>>>>      msn: margusja at kodila.ee
> >>>>>>      skype: margusja
> >>>>>>
> >>>>>>
> >>>>>>      On 1/20/11 10:09 AM, Margusja wrote:
> >>>>>>>        Hi
> >>>>>>>
> >>>>>>>        I have two separate Drupal instances (Pressflow 6.19) In first one the
> >>>>>>>        local cache works fine. Sql log:
> >>>>>>>                    326 Query       SET NAMES "utf8"
> >>>>>>>                    326 Query       SELECT 1 FROM access WHERE type = 'host' AND
> >>>>>>>        '195.50.208.170' LIKE mask AND status = 0 LIMIT 0, 1
> >>>>>>>                    326 Query       SELECT data, created, headers, expire,
> >>>>>>>        serialized FROM cache WHERE cid = 'variables'
> >>>>>>>                    326 Query       SELECT data, created, headers, expire,
> >>>>>>>        serialized FROM cache_page WHERE cid = 'http://IP/path/to/node'
> >>>>>>>                    326 Query       SELECT name, filename, throttle FROM system
> >>>>>>>        WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight
> >>>>>>>        ASC, filename ASC
> >>>>>>>                    326 Query       SELECT name, filename, throttle FROM system
> >>>>>>>        WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight
> >>>>>>>        ASC, filename ASC
> >>>>>>>                    326 Quit
> >>>>>>>
> >>>>>>>        But If I request the same node in the second machine. The code is same,
> >>>>>>>        then the Sql log is:
> >>>>>>>                      122 Quit
> >>>>>>>                      123 Query       SET NAMES "utf8"
> >>>>>>>                      123 Query       SELECT 1 FROM access WHERE type = 'host'
> >>>>>>>        AND 'IP' LIKE mask AND status = 0 LIMIT 0, 1
> >>>>>>>                      123 Query       INSERT INTO semaphore (name, value, expire)
> >>>>>>>        VALUES ('variable_cache_regenerate',
> >>>>>>>        '17865562914d37e5d81acd80.47344784', 1295508982.1098)
> >>>>>>>                      123 Query       SELECT * FROM variable
> >>>>>>>                      123 Query       DELETE FROM semaphore WHERE name =
> >>>>>>>        'variable_cache_regenerate' AND value = '17865562914d37e5d81acd80.47344784'
> >>>>>>>                      123 Query       SELECT name, filename, throttle FROM system
> >>>>>>>        WHERE type = 'module' AND status = 1 AND bootstrap = 1 ORDER BY weight
> >>>>>>>        ASC, filename ASC
> >>>>>>>                      123 Query       SELECT * FROM languages ORDER BY weight
> >>>>>>>        ASC, name ASC
> >>>>>>>                      123 Query       SELECT dst FROM url_alias LIMIT 0, 1
> >>>>>>>                      123 Query       SELECT src FROM url_alias WHERE dst =
> >>>>>>>        'hoiused-ja-investeerimine' AND language IN('et', '') ORDER BY language
> >>>>>>>        DESC, pid DESC
> >>>>>>>                      123 Query       SELECT name, filename, throttle FROM system
> >>>>>>>        WHERE type = 'module' AND status = 1 ORDER BY weight ASC, filename ASC
> >>>>>>>                      123 Query       INSERT INTO semaphore (name, value, expire)
> >>>>>>>        VALUES ('locale_cache_et', '17865562914d37e5d81acd80.47344784',
> >>>>>>>        1295508982.4035)
> >>>>>>>                      123 Query       SELECT s.source, t.translation, t.language
> >>>>>>>        FROM locales_source s LEFT JOIN locales_target t ON s.lid = t.lid AND
> >>>>>>>        t.language = 'et' WHERE s.textgroup = 'default' AND s.version = '6.19'
> >>>>>>>        AND LENGTH(s.source)<         75
> >>>>>>>                      123 Query       DELETE FROM semaphore WHERE name =
> >>>>>>>        'locale_cache_et' AND value = '17865562914d37e5d81acd80.47344784'
> >>>>>>>                      123 Query       SELECT s.lid, t.translation, s.version FROM
> >>>>>>>        locales_source s LEFT JOIN locales_target t ON s.lid = t.lid AND
> >>>>>>>        t.language = 'et' WHERE s.source = 'Stores details about batches
> >>>>>>>        (processes that run in multiple HTTP requests).' AND s.textgroup =
> >>>>>>>        'default'
> >>>>>>>        ....
> >>>>>>>        ....
> >>>>>>>        loads of SQLs
> >>>>>>>
> >>>>>>>        The main question why does the last one ask something from semaphore? In
> >>>>>>>        both servers access table is empty. At first I thought the condition
> >>>>>>>        came from that SQL: SELECT 1 FROM access WHERE type = 'host' AND 'IP'
> >>>>>>>        LIKE mask AND status = 0 LIMIT 0, 1 but as I said in both servers access
> >>>>>>>        table is empty.
> >>>>>>>
> >>>>>>>        In both solutions caches are enabled.
> >>>>>>>
> >>>>>>>        Any hints?
> >>>>>>>


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