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Using mysqld (latest xampp version). My.ini

port= 3306
socket = "D:/xampp/mysql/mysql.sock"
basedir = "D:/xampp/mysql"
tmpdir = "D:/xampp/tmp"
datadir = "D:/xampp/mysql/data"
pid_file = ""
key_buffer = 32M
max_allowed_packet = 4M
table_cache = 64
sort_buffer_size = 2M
net_buffer_length = 8K
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
log_error = "mysql_error.log"

query_cache_size = 32M
thread_concurrency = 4
table_open_cache = 512
wait_timeout = 600

max_connections = 250

CPU parameters are {i5, 4GB ram} Computer dedicated to MySQL and Apache.

DB using only MyISAM tables. Consists of few dozen tables with < 100k records. One table has logs (> 2m records and usually in write-only mode). All tables have indexes. No queries are fired with more than 10ms execution time.

Usually at 19:00 GMT+2 server stops responding (hangs, with 0% load) for 20-60 seconds, then resumes work normally. No activity for clients are allowed during this hang time.

What this can be? Any scheduled maintenance?

I've done "show processlist" There are countless connections with "Waiting for table lock" and one "Writing to net" on localhost computer.

Query is fairly simple and cannot be long. (it's begin queried like 2-3 times per second, and these hangs happend like once in few hours)

Any idea what might be causing it? (mb some net catch, buffer)

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migrated from Oct 8 '13 at 10:26

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Running Windows, correct? I'd check the Scheduled Tasks in the Control Panel. – jerdiggity Oct 8 '13 at 6:37
Using MyISAM isn't the best of decisions IMO, but that's besides the point. More details are required in order for you to get an answer: are you using replication? are there crons running? What type of connections are you using (not persistant connections, I hope...)? And how are you connection (what extension, when do you connect, when do you disconnect, are you using transactions?...). Even if you were to answer these questions, this question doesn't fit SO, it should be on the DBA exchange site, I do think – Elias Van Ootegem Oct 8 '13 at 6:38
If you execute show processlist; during this time do you see anything strange? – sal00m Oct 8 '13 at 6:40
Apache has ~17 persistent connections (I have ~100-200 php queries / second) and creating a connection every time is really time consuming. No transactions. Php using only simple queries. < 0.01s No cron jobs. No replications. Will check tasks and processes. Thank you. – Anfet Oct 8 '13 at 12:31
Usual problem is I cannot even connect to the server during those outages. – Anfet Oct 8 '13 at 12:32

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