Lost connection to MySQL server - need help.
Hello, I got a strange problem related to a production server. It has been working OK for months, but yesterday it start to fail. There are several batch scripts using the database in addition to a web application using it. The php scripts running in batch mode began to get: mysql_connect(): Lost connection to MySQL server at 'reading initial communication packet', system error: 111 I stopped the server and restarted it and everything seems to work OK for hours but when the load start to increase, the errors begin to appear again. Today I noticed that after I starte phpMyAdmin and selected one of the databases, phpMyAdmin was hanging and the batch scripts began to fail again. Seems like the server does not handle much load anymore. What's strange is the memory usage. The server is a quad core cpu with 48 Gb memory, where 28 Gb is allocated to innodb (we mostly use innodb). But when using top command, I noticed this: VIRT: 33.9g RES: 9.4g SWAP: 23g at this time over 11G memory is free. vm.swappiness is set to 0. I find it strange that the server is not able to use physical memory but use swap instead. The amount of cpu time used for swapping is rather high during sql queries. The amount of RESident memory may increase slowly over time but very slowly (it can take hours before it increase to 20+ Gb). [PS: I also got a MySQL server running at a dedicated host at home, where the it seem to use the memory as I except it to use: PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ SWAP DATA COMMAND 1462 mysql 20 0 30.0g 27g 3900 S 0.3 87.3 2633:14 844m 29g mysqld ] I would like to have some suggestions what I can do to solve this problem. I have google'd it but found nothing that seem to solve my case. Server: OS: Debian 6 MySQL: 5.1.61-0+squeeze1 my.cnf: # # The MySQL database server configuration file. # [client] port= 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice= 0 [mysqld] # # * Basic Settings # user= mysql pid-file= /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port= 3306 basedir = /usr datadir = /database/mysql tmpdir = /tmp language= /usr/share/mysql/english skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address= 127.0.0.1 ## All applications use 127.0.0.1 when connectiong to the db. # # * Fine Tuning # #key_buffer = 16M max_allowed_packet = 64M thread_stack= 192K #thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP # # * Query Cache Configuration # query_cache_limit = 1M # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin= /var/log/mysql/mysql-bin.log expire_logs_days= 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! thread_cache_size = 192 table_cache = 768 ## key_buffer = 64M ## sort_buffer_size = 256K ## read_buffer_size = 256K ## read_rnd_buffer_size = 256K tmp_table_size=32M max_heap_table_size=32M query_cache_size=128M query_cache_type=2 innodb_open_files=1000 innodb_buffer_pool_size = 28G innodb_additional_mem_pool_size = 8M innodb_flush_log_at_trx_commit = 1 innodb_support_xa = 0 innodb_lock_wait_timeout = 50 ## innodb_flush_method=O_DIRECT innodb_log_files_in_group = 2 ## innodb_log_file_size = 128M innodb_log_buffer_size = 8M innodb_thread_concurrency = 14 innodb_file_per_table max_connections = 100 binlog_cache_size = 1M sort_buffer_size= 16M join_buffer_size= 16M ft_min_word_len = 1 ft_max_word_len = 84 ft_stopword_file= '' default_table_type = InnoDB key_buffer = 2G read_buffer_size= 2M read_rnd_buffer_size= 16M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_max_extra_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab
Re: Lost connection to MySQL server - need help.
You might want to comment bind-address= 127.0.0.1 in your my.cnf and restart mysql server. On 12/10/13 10:49, Jørn Dahl-Stamnes wrote: Hello, I got a strange problem related to a production server. It has been working OK for months, but yesterday it start to fail. There are several batch scripts using the database in addition to a web application using it. The php scripts running in batch mode began to get: mysql_connect(): Lost connection to MySQL server at 'reading initial communication packet', system error: 111 I stopped the server and restarted it and everything seems to work OK for hours but when the load start to increase, the errors begin to appear again. Today I noticed that after I starte phpMyAdmin and selected one of the databases, phpMyAdmin was hanging and the batch scripts began to fail again. Seems like the server does not handle much load anymore. What's strange is the memory usage. The server is a quad core cpu with 48 Gb memory, where 28 Gb is allocated to innodb (we mostly use innodb). But when using top command, I noticed this: VIRT: 33.9g RES: 9.4g SWAP: 23g at this time over 11G memory is free. vm.swappiness is set to 0. I find it strange that the server is not able to use physical memory but use swap instead. The amount of cpu time used for swapping is rather high during sql queries. The amount of RESident memory may increase slowly over time but very slowly (it can take hours before it increase to 20+ Gb). [PS: I also got a MySQL server running at a dedicated host at home, where the it seem to use the memory as I except it to use: PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ SWAP DATA COMMAND 1462 mysql 20 0 30.0g 27g 3900 S 0.3 87.3 2633:14 844m 29g mysqld ] I would like to have some suggestions what I can do to solve this problem. I have google'd it but found nothing that seem to solve my case. Server: OS: Debian 6 MySQL: 5.1.61-0+squeeze1 my.cnf: # # The MySQL database server configuration file. # [client] port= 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice= 0 [mysqld] # # * Basic Settings # user= mysql pid-file= /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port= 3306 basedir = /usr datadir = /database/mysql tmpdir = /tmp language= /usr/share/mysql/english skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address= 127.0.0.1 ## All applications use 127.0.0.1 when connectiong to the db. # # * Fine Tuning # #key_buffer = 16M max_allowed_packet = 64M thread_stack= 192K #thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP # # * Query Cache Configuration # query_cache_limit = 1M # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin= /var/log/mysql/mysql-bin.log expire_logs_days= 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! thread_cache_size = 192 table_cache = 768 ## key_buffer = 64M ## sort_buffer_size = 256K ## read_buffer_size = 256K ## read_rnd_buffer_size = 256K tmp_table_size=32M max_heap_table_size=32M query_cache_size=128M query_cache_type=2 innodb_open_files=1000 innodb_buffer_pool_size = 28G innodb_additional_mem_pool_size = 8M innodb_flush_log_at_trx_commit = 1 innodb_support_xa = 0 innodb_lock_wait_timeout = 50 ## innodb_flush_method=O_DIRECT innodb_log_files_in_group = 2 ## innodb_log_file_size = 128M innodb_log_buffer_size = 8M innodb_thread_concurrency = 14 innodb_file_per_table max_connections = 100 binlog_cache_size = 1M sort_buffer_size= 16M join_buffer_size= 16M ft_min_word_len = 1 ft_max_word_len = 84 ft_stopword_file= '' default_table_type = InnoDB key_buffer = 2G read_buffer_size= 2M read_rnd_buffer_size= 16M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_max_extra_sort_file_size = 10G myisam_repair_threads
Re: Lost connection to MySQL server - need help.
On Saturday 12 October 2013 12:01, nixofortune wrote: You might want to comment bind-address= 127.0.0.1 in your my.cnf and restart mysql server. It does not explain why it works under low load and not under high load. However, I seem to have found something. When I started phpMyAdmin and selected one of the database, the server went away again and I found this in /var/log/syslog: Oct 12 11:53:33 cebycny mysqld: 131012 11:53:33 InnoDB: Assertion failure in thread 140182892447488 in file ../../../storage/innobase/handler/ha_innodb.cc line 8066 Oct 12 11:53:33 cebycny mysqld: InnoDB: Failing assertion: auto_inc 0 Oct 12 11:53:33 cebycny mysqld: InnoDB: We intentionally generate a memory trap. Oct 12 11:53:33 cebycny mysqld: InnoDB: Submit a detailed bug report to http://bugs.mysql.com. Oct 12 11:53:33 cebycny mysqld: InnoDB: If you get repeated assertion failures or crashes, even Oct 12 11:53:33 cebycny mysqld: InnoDB: immediately after the mysqld startup, there may be Oct 12 11:53:33 cebycny mysqld: InnoDB: corruption in the InnoDB tablespace. Please refer to Oct 12 11:53:33 cebycny mysqld: InnoDB: http://dev.mysql.com/doc/refman/5.1/en/forcing-innodb-recovery.html Oct 12 11:53:33 cebycny mysqld: InnoDB: about forcing recovery. Oct 12 11:53:33 cebycny mysqld: 09:53:33 UTC - mysqld got signal 6 ; Oct 12 11:53:33 cebycny mysqld: This could be because you hit a bug. It is also possible that this binary Oct 12 11:53:33 cebycny mysqld: or one of the libraries it was linked against is corrupt, improperly built, Oct 12 11:53:33 cebycny mysqld: or misconfigured. This error can also be caused by malfunctioning hardware. Oct 12 11:53:33 cebycny mysqld: We will try our best to scrape up some info that will hopefully help Oct 12 11:53:33 cebycny mysqld: diagnose the problem, but since we have already crashed, Oct 12 11:53:33 cebycny mysqld: something is definitely wrong and this may fail. Oct 12 11:53:33 cebycny mysqld: Oct 12 11:53:33 cebycny mysqld: key_buffer_size=2147483648 Oct 12 11:53:33 cebycny mysqld: read_buffer_size=2097152 Oct 12 11:53:33 cebycny mysqld: max_used_connections=8 Oct 12 11:53:33 cebycny mysqld: max_threads=100 Oct 12 11:53:33 cebycny mysqld: thread_count=2 Oct 12 11:53:33 cebycny mysqld: connection_count=2 Oct 12 11:53:33 cebycny mysqld: It is possible that mysqld could use up to Oct 12 11:53:33 cebycny mysqld: key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 3941387 K bytes of memory Oct 12 11:53:33 cebycny mysqld: Hope that's ok; if not, decrease some variables in the equation. Oct 12 11:53:33 cebycny mysqld: Oct 12 11:53:33 cebycny mysqld: Thread pointer: 0x7f7f1bf997c0 Oct 12 11:53:33 cebycny mysqld: Attempting backtrace. You can use the following information to find out Oct 12 11:53:33 cebycny mysqld: where mysqld died. If you see no messages after this, something went Oct 12 11:53:33 cebycny mysqld: terribly wrong... Oct 12 11:53:33 cebycny mysqld: stack_bottom = 7f7edf81fe88 thread_stack 0x3 Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(my_print_stacktrace+0x29) [0x7f7edff62b59] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(handle_fatal_signal+0x483) [0x7f7edfd774a3] Oct 12 11:53:33 cebycny mysqld: /lib/libpthread.so.0(+0xeff0) [0x7f7edf4c9ff0] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(gsignal+0x35) [0x7f7eddf6c1b5] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(abort+0x180) [0x7f7eddf6efc0] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::innobase_peek_autoinc()+0x8f) [0x7f7edfe1fa2f] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::info_low(unsigned int, bool)+0x18f) [0x7f7edfe2524f] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::update_create_info(st_ha_create_information*)+0x29) [0x7f7edfe256b9] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(+0x49e3dc) [0x7f7edfd953dc] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysqld_show_create(THD*, TABLE_LIST*)+0x7a8) [0x7f7edfd9d388] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysql_execute_command(THD*)+0x184a) [0x7f7edfc7cb0a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysql_parse(THD*, char*, unsigned int, char const**)+0x3fb) [0x7f7edfc80dbb] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(dispatch_command(enum_server_command, THD*, char*, unsigned int)+0x115a) [0x7f7edfc81f2a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(do_command(THD*)+0xea) [0x7f7edfc8285a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(handle_one_connection+0x235) [0x7f7edfc74435] Oct 12 11:53:33 cebycny mysqld: /lib/libpthread.so.0(+0x68ca) [0x7f7edf4c18ca] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(clone+0x6d) [0x7f7ede00992d] Oct 12 11:53:33 cebycny mysqld: Oct 12 11:53:33 cebycny mysqld: Trying to get some variables. Oct 12 11:53:33 cebycny mysqld: Some pointers may be invalid and cause the dump to abort. Oct 12 11:53:33 cebycny mysqld: Query (7f7f1c0dcbc0): SHOW CREATE TABLE `calculation` Oct 12
Re: Lost connection to MySQL server - need help.
Could be a crash related to innodb data dictionary being out of sync. Could be a bug. http://bugs.mysql.com/bug.php?id=55277 On 12 Oct 2013 11:21, Jørn Dahl-Stamnes sq...@dahl-stamnes.net wrote: On Saturday 12 October 2013 12:01, nixofortune wrote: You might want to comment bind-address= 127.0.0.1 in your my.cnf and restart mysql server. It does not explain why it works under low load and not under high load. However, I seem to have found something. When I started phpMyAdmin and selected one of the database, the server went away again and I found this in /var/log/syslog: Oct 12 11:53:33 cebycny mysqld: 131012 11:53:33 InnoDB: Assertion failure in thread 140182892447488 in file ../../../storage/innobase/handler/ha_innodb.cc line 8066 Oct 12 11:53:33 cebycny mysqld: InnoDB: Failing assertion: auto_inc 0 Oct 12 11:53:33 cebycny mysqld: InnoDB: We intentionally generate a memory trap. Oct 12 11:53:33 cebycny mysqld: InnoDB: Submit a detailed bug report to http://bugs.mysql.com. Oct 12 11:53:33 cebycny mysqld: InnoDB: If you get repeated assertion failures or crashes, even Oct 12 11:53:33 cebycny mysqld: InnoDB: immediately after the mysqld startup, there may be Oct 12 11:53:33 cebycny mysqld: InnoDB: corruption in the InnoDB tablespace. Please refer to Oct 12 11:53:33 cebycny mysqld: InnoDB: http://dev.mysql.com/doc/refman/5.1/en/forcing-innodb-recovery.html Oct 12 11:53:33 cebycny mysqld: InnoDB: about forcing recovery. Oct 12 11:53:33 cebycny mysqld: 09:53:33 UTC - mysqld got signal 6 ; Oct 12 11:53:33 cebycny mysqld: This could be because you hit a bug. It is also possible that this binary Oct 12 11:53:33 cebycny mysqld: or one of the libraries it was linked against is corrupt, improperly built, Oct 12 11:53:33 cebycny mysqld: or misconfigured. This error can also be caused by malfunctioning hardware. Oct 12 11:53:33 cebycny mysqld: We will try our best to scrape up some info that will hopefully help Oct 12 11:53:33 cebycny mysqld: diagnose the problem, but since we have already crashed, Oct 12 11:53:33 cebycny mysqld: something is definitely wrong and this may fail. Oct 12 11:53:33 cebycny mysqld: Oct 12 11:53:33 cebycny mysqld: key_buffer_size=2147483648 Oct 12 11:53:33 cebycny mysqld: read_buffer_size=2097152 Oct 12 11:53:33 cebycny mysqld: max_used_connections=8 Oct 12 11:53:33 cebycny mysqld: max_threads=100 Oct 12 11:53:33 cebycny mysqld: thread_count=2 Oct 12 11:53:33 cebycny mysqld: connection_count=2 Oct 12 11:53:33 cebycny mysqld: It is possible that mysqld could use up to Oct 12 11:53:33 cebycny mysqld: key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 3941387 K bytes of memory Oct 12 11:53:33 cebycny mysqld: Hope that's ok; if not, decrease some variables in the equation. Oct 12 11:53:33 cebycny mysqld: Oct 12 11:53:33 cebycny mysqld: Thread pointer: 0x7f7f1bf997c0 Oct 12 11:53:33 cebycny mysqld: Attempting backtrace. You can use the following information to find out Oct 12 11:53:33 cebycny mysqld: where mysqld died. If you see no messages after this, something went Oct 12 11:53:33 cebycny mysqld: terribly wrong... Oct 12 11:53:33 cebycny mysqld: stack_bottom = 7f7edf81fe88 thread_stack 0x3 Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(my_print_stacktrace+0x29) [0x7f7edff62b59] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(handle_fatal_signal+0x483) [0x7f7edfd774a3] Oct 12 11:53:33 cebycny mysqld: /lib/libpthread.so.0(+0xeff0) [0x7f7edf4c9ff0] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(gsignal+0x35) [0x7f7eddf6c1b5] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(abort+0x180) [0x7f7eddf6efc0] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::innobase_peek_autoinc()+0x8f) [0x7f7edfe1fa2f] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::info_low(unsigned int, bool)+0x18f) [0x7f7edfe2524f] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(ha_innobase::update_create_info(st_ha_create_information*)+0x29) [0x7f7edfe256b9] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(+0x49e3dc) [0x7f7edfd953dc] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysqld_show_create(THD*, TABLE_LIST*)+0x7a8) [0x7f7edfd9d388] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysql_execute_command(THD*)+0x184a) [0x7f7edfc7cb0a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(mysql_parse(THD*, char*, unsigned int, char const**)+0x3fb) [0x7f7edfc80dbb] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(dispatch_command(enum_server_command, THD*, char*, unsigned int)+0x115a) [0x7f7edfc81f2a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(do_command(THD*)+0xea) [0x7f7edfc8285a] Oct 12 11:53:33 cebycny mysqld: /usr/sbin/mysqld(handle_one_connection+0x235) [0x7f7edfc74435] Oct 12 11:53:33 cebycny mysqld: /lib/libpthread.so.0(+0x68ca) [0x7f7edf4c18ca] Oct 12 11:53:33 cebycny mysqld: /lib/libc.so.6(clone+0x6d) [0x7f7ede00992d] Oct 12
Re: Lost connection to MySQL server - need help.
On Saturday 12 October 2013 13:07, Andrew Moore wrote: Could be a crash related to innodb data dictionary being out of sync. Could be a bug. Seems like a bug yes. However, we had a strange situation yesterday when we had several processes in the state copying to tmp table (if i remember the exact phrase). After witing 2 seconds, I restarted the server. It seemed to work OK until the backup started. Perhaps we should restore the database that I suspect cause this, in order to rebuild the complete database. -- Jørn Dahl-Stamnes homepage: http://photo.dahl-stamnes.net/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: Lost connection to MySQL server - need help.
Am 12.10.2013 17:02, schrieb Jørn Dahl-Stamnes: On Saturday 12 October 2013 13:07, Andrew Moore wrote: Could be a crash related to innodb data dictionary being out of sync. Could be a bug. Seems like a bug yes. However, we had a strange situation yesterday when we had several processes in the state copying to tmp table (if i remember the exact phrase). After witing 2 seconds, I restarted the server. It seemed to work OK until the backup started so someone did optimize table on a large table you do yourself not a favour restarting the server in such a moment signature.asc Description: OpenPGP digital signature
Re: Lost connection to MySQL server - need help.
On Saturday 12 October 2013 17:36, Reindl Harald wrote: so someone did optimize table on a large table you do yourself not a favour restarting the server in such a moment 7 hours before the server was shut down, we did a alter table to add a primary key to a table that is read-only from the web application. -- Jørn Dahl-Stamnes homepage: http://photo.dahl-stamnes.net/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: Lost connection to MySQL server - need help.
Am 12.10.2013 19:45, schrieb Jørn Dahl-Stamnes: On Saturday 12 October 2013 17:36, Reindl Harald wrote: so someone did optimize table on a large table you do yourself not a favour restarting the server in such a moment 7 hours before the server was shut down, we did a alter table to add a primary key to a table that is read-only from the web application. which means the table is most likely completly copied in a temp file and depending on the table size this takes time - you killed the alter table i guess signature.asc Description: OpenPGP digital signature
Re: Lost connection to MySQL server - need help.
We had a similar issue a bit back - and although it sounds similar - based on your followups it probably isnt, but will just toss this out there anyhows. We were experiencing connection timeouts when load would ramp up. Doing some digging we learned that our firewall between the servers bandwidth would get consumed by a large wordpress load - and this in essence backed up the rest of the requests until they timed out. We fixed that load issue which reduced the data passing through and have expereinced a significant performance boost in our app let alone reduction of these timeout issues On Sat, Oct 12, 2013 at 12:56 PM, Reindl Harald h.rei...@thelounge.netwrote: Am 12.10.2013 19:45, schrieb Jørn Dahl-Stamnes: On Saturday 12 October 2013 17:36, Reindl Harald wrote: so someone did optimize table on a large table you do yourself not a favour restarting the server in such a moment 7 hours before the server was shut down, we did a alter table to add a primary key to a table that is read-only from the web application. which means the table is most likely completly copied in a temp file and depending on the table size this takes time - you killed the alter table i guess
Re: Lost connection to MySQL server - need help.
sounds like a scheduler issue did you try deadline? http://en.wikipedia.org/wiki/Deadline_scheduler on Linux systems pass elevator=deadline as kernel param Am 12.10.2013 20:58, schrieb Chris McKeever: We had a similar issue a bit back - and although it sounds similar - based on your followups it probably isnt, but will just toss this out there anyhows. We were experiencing connection timeouts when load would ramp up. Doing some digging we learned that our firewall between the servers bandwidth would get consumed by a large wordpress load - and this in essence backed up the rest of the requests until they timed out. We fixed that load issue which reduced the data passing through and have expereinced a significant performance boost in our app let alone reduction of these timeout issues On Sat, Oct 12, 2013 at 12:56 PM, Reindl Harald h.rei...@thelounge.netwrote: Am 12.10.2013 19:45, schrieb Jørn Dahl-Stamnes: On Saturday 12 October 2013 17:36, Reindl Harald wrote: so someone did optimize table on a large table you do yourself not a favour restarting the server in such a moment 7 hours before the server was shut down, we did a alter table to add a primary key to a table that is read-only from the web application. which means the table is most likely completly copied in a temp file and depending on the table size this takes time - you killed the alter table i guess signature.asc Description: OpenPGP digital signature
