I have a server (MS Windows Server 2012 R2 Datacenter 64GB RAM 2TB+ disk space) running mySQL 5.0. When I start the mySQL server, right off the bat it allocates 214,000 handles. Is that normal? I've been looking into this because I am trying to run an application that executes multiple unique queries over thousands of records and it is just crawling.
I have changed query_cache_size from 160M to 0M in the my.ini file as query caching will not benefit this application. Still no change in handles. I'm not sure what else I can do to fix this. Does anyone have any ideas?
The server is:
MySQL 5.0.60sp1-enterprise-gpl-nt
There are a ton of options. Here are what I think are the relevant ones (I could be wrong I am not an expert)
[mysqld]
default_storage_engine=InnoDB
innodb_file_per_table
innodb_flush_method=unbuffered
lower_case_table_names=2
max_allowed_packet=48M
max_heap_table_size=64777216
max_connections=3010
query_cache_size=0M
table_cache=6020
tmp_table_size=16M
thread_cache_size=64
myisam_max_sort_file_size=100G
myisam_max_extra_sort_file_size=100G
key_buffer_size=20M
read_buffer_size=64K
read_rnd_buffer_size=256K
innodb_additional_mem_pool_size=15M
innodb_flush_log_at_trx_commit=1
innodb_buffer_pool_size=709M
innodb_thread_concurrency=50
Related
I have a really big website built old fashioned with PHP & MYSQL.
I have more than 1,000 different queries in my website, on different PHP pages, and it's really hard to update all of them to MYSQLI.
I bought VPS server with 4GB RAM and in the past months I experience really slow page loads.
When I restart my server, everything runs smoothly, but after couple of hours/days the website is getting muchu slower with loading time of 3+ seconds for a page load. I notice that the mysqld service is increasing and increasing in memory usage, from 80MB on server restart it reached about 400MB and more of usage.
I put in the end of my index.php mysql_close() but it seem like the connection number still increasing.
Questions
What can cause unlimited increment in mysql memory usage?
Updating all my queries to MYSQLI may improve the performance?
Some information:
innodb_version
5.5.31
protocol_version
10
slave_type_conversions
version
5.5.31-log
version_comment
MySQL Community Server (GPL)
version_compile_machine
x86_64
version_compile_os
Linux
storage engine: Mixed (Somes tables are INNODB,some tables are MyISAM.
my.cnf:
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
max-connections=100000
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
thread_cache_size=5
table_open_cache=99390
sort_buffer_size=512M
read_rnd_buffer_size=512M
query_cache_size=512M
query_cache_limit = 16M
query_cache_type = 1
slow_query_log=1
slow_query_log_file=slow_query_log.log #
long_query_time=5
log-queries-not-using-indexes=1
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
I have about ~6-7 queries running when I use show processlist
max-connections=100000 -- Yikes! Drop to 1000
table_open_cache=99390 -- drop to, say, 2000
sort_buffer_size=512M -- drop to 1% of RAM, say, 40M
read_rnd_buffer_size=512M -- ditto
query_cache_size=512M -- too big; slows things down; drop to 40M
long_query_time=5 -- not low enough to catch much; drop to 2
log-queries-not-using-indexes=1 -- clutters the slowlog without providing much info; change to 0
You did not say which Engine you are using. Read this for advice on MyISAM and InnoDB.
1000 pages -- that's not too many.
Which web server? If Apache, don't set MaxClients to more than 20.
2022 postscript: The query_cache_size and query_cache_type variables have been removed from mySQL 8.0.3+.
We are not able to create a stable configuration of a production server with MySQL and Tomcat Application Server. The MySQL throws very often an error:
MySQL: Out of memory (Needed 429496728 bytes)
It was a Windows Server 2012 with 64 GB of RAM. We see in the process tab, that the MySQLd commited 64 GB of RAM (that means all the available RAM in the server).
For your explaination, the Application uses completly inMemory based Tables in the MySQL Server.
See the my.ini Configuration
[client]
port=3306
[mysql]
default-character-set=utf8
[mysqld]
port=3306
basedir="F:/MySQL Server 5.6/"
datadir="F:/MySQL Server 5.6/data/"
character-set-server=utf8
default-storage-engine=MyISAM
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
max_connections=200
query_cache_size=0
# table_cache=256
tmp_table_size=6G
max_heap_table_size=6G
max_tmp_tables=2048
open_files_limit=40000
thread_cache_size=8
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=32M
myisam_use_mmap=0
concurrent_insert=2
key_buffer_size=2G
read_buffer_size=512M
read_rnd_buffer_size=512M
sort_buffer_size=128M
bulk_insert_buffer_size=32M
#skip-innodb
innodb_additional_mem_pool_size=15M
innodb_flush_log_at_trx_commit=1
innodb_log_buffer_size=7M
innodb_buffer_pool_size=686M
innodb_log_file_size=343M
innodb_thread_concurrency=34
slow_query_log=1
log-queries-not-using-indexes=1
long_query_time=1
log-output=FILE,TABLE
slow_query_log_file="F:/MySQL Server 5.6/localhost-slow-query.log"
event-scheduler=ON
Does anybody have a suitable solution to get this fixed?
We also use the MySQL Tuner to get informations, here the results:
What I cannot attach is the MySQL Tuner results as image (too few reputations). But look here.
Up for 39days
Data in Memory Tables 42G (Tables:281)
Data in MyISAM tables 31G (Tables 668)
total buffers: 2.3G global + 144.5M per Thread (200 max threads)
maximum possible memory usage: 30.5G (47% of installed RAM)
Key buffer size /total MyISAM indixes: 640M/7.0G
query cache disabled
joins performed without indixes: 337737
Our Access 2010 database recently hit the 2GB file size limit, so I ported the database to MySQL.
I installed MySQL Server 5.6.1 x64 on Windows Server 2008 x64.
All OS updates and patches are loaded.
I am using the MySQL ODBC 5.2w x64 Driver, as it seems to be the fastest.
My box has an i7-3960X with 64GB RAM and a 480GB SSD.
I use Access Query Designer as I prefer the interface and I regularly need to append missing records from one table to the other.
As a test, I have a simple Access Database with two linked tables:
tblData links to another Access Database and
tblOnline uses a SYSTEM DSN to a linked ODBC table.
Both tables contain over 10 million records.
Some of my ported working tables already have over 30 million records.
To select records to append, I use a field called INDBYN which is either true or false.
First I run an Update query on tblData:
UPDATE tblData SET tblData.InDBYN = False;
Then I update all matching records:
UPDATE tblData INNER JOIN tblData ON tblData.IDMaster = tblOnline.IDMaster SET tblData.InDBYN = True;
This works reasonably fast, even to the linked ODBC table.
Lastly I Append all records where INDBYN is False to tblOnline.
This is also acceptable speed, although slower than appends to a Linked Access table.
Within Access everything works 100% and is incredibly fast, except the DB is getting too big.
On the Linked Access Table, it takes 2m15s to update 11,500,000 records.
However, I now need to move the SOURCE table to MySQL, as it is reaching the 2GB limit.
So in future I will need to run the UPDATE statement on a linked ODBC table.
So far, when I run the same simple UPDATE query on the linked ODBC table it runs for more than 20 minutes, and then bombs out saying the query has exceeded the 2GB memory limit.
Both tables are identical in structure.
I do not know how to resolve this and need advice please.
I prefer to use Access as the front-end as I have hundreds of queries already designed for the app, and there is no time to re-develop the app.
I use the InnoDB engine and have tried various tweaks without success. Since my database uses relational tables, it looked like the best option to use INNODB as opposed to MyISAM.
I have turned doublewrite on and off and tried various buffer pool sizes, including query cache. It does not make a difference on this particular query.
My current my.ini file looks like this:
#-----------------------------------------------------------------------
# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
[client]
no-beep
port=3306
[mysql]
default-character-set=utf8
server_type=3
[mysqld]
port=3306
basedir="C:\Program Files\MySQL\MySQL Server 5.6\"
datadir="E:\MySQLData\data\"
character-set-server=utf8
default-storage-engine=INNODB
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
log-output=FILE
general-log=0
general_log_file="SQLSERVER.log"
slow-query-log=1
slow_query_log_file="SQLSERVER-slow.log"
long_query_time=10
log-error="SQLSERVER.err"
max_connections=100
query_cache_size = 20M
table_open_cache=2000
tmp_table_size=502M
thread_cache_size=9
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=1002M
key_buffer_size=8M
read_buffer_size=64K
read_rnd_buffer_size=256K
sort_buffer_size=256K
innodb_additional_mem_pool_size=32M
innodb_flush_log_at_trx_commit = 1
innodb_log_buffer_size=16M
innodb_buffer_pool_size = 48G
innodb_log_file_size=48M
innodb_thread_concurrency = 0
innodb_autoextend_increment=64M
innodb_buffer_pool_instances=8
innodb_concurrency_tickets=5000
innodb_old_blocks_time=1000
innodb_open_files=2000
innodb_stats_on_metadata=0
innodb_file_per_table=1
innodb_checksum_algorithm=0
back_log=70
flush_time=0
join_buffer_size=256K
max_allowed_packet=4M
max_connect_errors=100
open_files_limit=4110
query_cache_type = 1
sort_buffer_size=256K
table_definition_cache=1400
binlog_row_event_max_size=8K
sync_relay_log=10000
sync_relay_log_info=10000
tmpdir = "G:/MySQLTemp"
innodb_write_io_threads = 16
innodb_doublewrite
innodb = ON
innodb_fast_shutdown = 1
query_cache_min_res_unit = 4096
query_cache_limit = 1048576
innodb_data_home_dir = "E:/MySQLData/data"
bulk_insert_buffer_size = 8388608
Any advice will be greatly appreciated. Thank you in advance.
Communication of MS Access with MySQL thru linked table is slow. Terribly slow. That is the fact which can't be changed. Why is it happening? Access firstly load data from MySQL, then it process the command and finally it puts the data back. In addition, it does this process row by row!
However, you can avoid this if you don't need to use parameters or data from local tables in your "update" query. (In another words - if your query is always same and it use only MySQL data)
Trick is to force MySQL server to process the query instead of Access! This can be achieved by creating "pass-thru" query in Access, where you can write directly your SQL code (in MySQL syntax). Access then sends this command to MySQL server and it is processed directly within that server. So your query will be almost as fast as doing it in local access table.
Access is a single-user system. MySQL with InnoDB is a transaction-protected multi-user system.
When you issue an UPDATE command that hits ten or so megarows, MySQL has to construct rollback information in case the operation fails before it hits all the rows. This takes a lot of time and memory.
Try switching your table access method to MyISAM if you're going to do these truly massive UPDATE and INSERT commands. MyISAM isn't transaction-protected so these operations may run faster.
You may find it helpful to do your data migration with some tool other than ODBC. ODBC is severely limited in its ability to handle lots of data, as you have discovered. For example, you could export your Access tables to flat files and then import them with a MySQL client program. See here... https://stackoverflow.com/questions/9185/what-is-the-best-mysql-client-application-for-windows
Once you've imported your data to MySQL, you then can run Access-based queries. But avoid UPDATE requests that hit everything in the database.
Ollie, I get your point on avoiding UPDATES that hit all rows. I use that to flag rows which are missing from the destination database, and it has been a quick and easy way to append only the missing rows. I see SQLyog has an import tool to Append new records only, but this still runs through all rows in the import table, and runs for hours. I will see if I can export only the data I want to CSV, but would still be nice to get the ODBC connector to work faster than present, if at all possible.
I have a MySQL 5.1.61 database running behind two load balanced Apache webservers hosting a fairly busy (100K uniques per day) Wordpress sites. I'm caching with Cloudflare, W3TC, and Varnish. Most of the time, the database server handles traffic very well. "show full processlist" shows 20-40 queries at any given time, with most being in the sleep state.
Periodically, though (particularly when traffic spikes or when a large number of comments are cleared), MySQL stops responding. I'll find 1000-1500 queries running, many "sending data", etc. No particular query seems to be straining the database (they're all standard Wordpress queries), but it just seems like the simultaneous volume of requests causes all queries to hang up. I'm (usually) still able to log in, to run "show full processlist", or other queries, but the 1000+ queries already in there just sit. The only solution seems to be to restart mysql (sometimes violently via kill -9 if I can't connect).
All tables are innodb, server has 8 cores, 24GB RAM, plenty of disk space, and the following is my my.cnf:
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
port=3306
skip-external-locking
skip-name-resolve
user=mysql
query_cache_type=1
query_cache_limit=16M
wait_timeout = 300
query_cache_size=128M
key_buffer_size=400M
thread_cache_size=50
table_cache=8192
skip-name-resolve
max_heap_table_size = 256M
tmp_table_size = 256M
innodb_file_per_table
innodb_buffer_pool_size = 5G
innodb_log_file_size=1G
#innodb_commit_concurrency = 32
#innodb_thread_concurrency = 32
innodb_flush_log_at_trx_commit = 0
thread_concurrency = 8
join_buffer_size = 256k
innodb_log_file_size = 256M
#innodb_concurrency_tickets = 220
thread_stack = 256K
max_allowed_packet=512M
max_connections=2500
# Default to using old password format for compatibility with mysql 3.x
# clients (those using the mysqlclient10 compatibility package).
old_passwords=1
#2012-11-03
#attempting a ram disk for tmp tables
tmpdir = /db/tmpfs01
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
Any suggestions how I can potentially improve MySQL config, or other steps to maintain database stability under heavy load?
Like has been said, think outside the box and do sone rooting around why these queries are slow or somehow hung. An oldie but a good source of problems even for (supposedly;) intelligent system engineers is load balancing causing issues across webserver or database sessions. With all that caching and load balancing going on, are you sure everything is always connecting end-to-end as intended?
I agree with alditis & Bjoern
I'm pretty noobish with mysql but running mysqltuner can reveal some config optimisations based on recent queries of the DB https://github.com/rackerhacker/MySQLTuner-perl
And if possible store the DB files on a physically separate partition from the OS, the OS can consume IO which slows the DB. Like with Bjoern's logrotate issue.
First have a look at basic system behavior at the moment of problems. Use both vmstat and iostat if you can find any issues. See if the system starts swapping (pi,po columns in vmstat) and if lots of IO is happening. This is the first step in debugging your problem.
Another source of useful information is SHOW INNODB STATUS. See for http://www.mysqlperformanceblog.com/2006/07/17/show-innodb-status-walk-through/ on how to interpret the output.
It might be that at a certain point in time your writes are killing read performance because they flush the query cache.
I have what seems to be a slowing MySQL restore, and am looking for some tuning advice (I am a PostgreSQL and SQL Server guy).
The dev server has 48GB of RAM, 8 cores, running Centos 6.2 64-bit and MySQL 5.1.61 (same as production MySQL), and 4 x 7200 RPM SAS drives in software managed RAID-10 / XFS. The only MySQL client process is the restore. The dump was taken with a plain mysqldump of all databases on the production server.
I have applied some of the options from http://derwiki.tumblr.com/post/24490758395/loading-half-a-billion-rows-into-mysql, including setting FOREIGN_KEY_CHECKS and UNIQUE_CHECKS to zero. I have included my.cnf below.
Monitoring the restore with mytop and pv (pv backup.sql | mysql -u root -p), it appears that the INSERT INTO statements begin to progressively get slower. qps shown by mytop starts at 3, and drops to 0 at 60% through the dump file. Not sure how accurate mytop is in this case, as 3 inserts (with values) still seems slow. htop shows < 10% CPU utilization on the CPU used by MySQL, and less than 8GB of the 48GB of RAM is being utilized.
Different databases, but similar restore techniques, run about 5-10x faster on the same server using PostgreSQL.
Ideas?
[mysqld]
# my.cnf
socket=/var/lib/mysql/mysql.sock
user=mysql
symbolic-links=0
slow-query-log
long_query_time = 60
log-slow-admin-statements
slow_query_log_file = /var/log/mysql_slow.log
innodb_buffer_pool_size = 2G
max_allowed_packet = 1G
key_buffer_size = 1G
concurrent_insert = 1
innodb_flush_log_at_trx_commit = 2
bulk_insert_buffer_size = 1G
innodb_flush_method = O_DIRECT
Sounds like your innodb indexes are slowing you down. If can change the way you dump the database you can remove all non-primary key indexes load the data then re-add them. Better still order the data to be loaded by the primary key. This is probably too much to ask.
Sounds like you are already aware of these tips: http://dev.mysql.com/doc/refman/5.5/en/optimizing-innodb-bulk-data-loading.html
The flush to disk operation (innodb_flush_log_at_trx_commit = 2) may be happening many times a second. Check your innodb_log_file_size * innodb_log_files_in_group is sufficient to avoid writing to disk too often.
(I assumed you are using Innodb from your settings)