watching queries per second (vmstat style) on MySQL

Good trick!

mysqladmin ext -ri 1 |grep -i -e queries -e \-

view raw vmsqlstat.sh hosted with ❤ by GitHub

	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Qcache_queries_in_cache | 5282 |
	| Queries | 669070336 |
	| Slow_queries | 2950563 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Innodb_data_pending_fsyncs | -1 |
	| Qcache_free_memory | -2440 |
	| Qcache_queries_in_cache | 1 |
	| Queries | 211 |
	| Slow_queries | 0 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Qcache_queries_in_cache | 0 |
	| Queries | 177 |
	| Slow_queries | 0 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Innodb_data_pending_fsyncs | -1 |
	| Innodb_os_log_pending_fsyncs | -1 |
	| Qcache_queries_in_cache | 0 |
	| Queries | 133 |
	| Slow_queries | 0 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Open_files | -8 |
	| Qcache_queries_in_cache | 0 |
	| Queries | 687 |
	| Slow_queries | 0 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	| Open_files | -2 |
	| Qcache_queries_in_cache | -13 |
	| Qcache_total_blocks | -12 |
	| Queries | 544 |
	| Slow_queries | 0 |
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+
	+-----------------------------------+--------------+

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:D

Compiling a .cpp source with OpenCV libs in MacOSX/Ubuntu 13.04

Yes!.... the way to run cpp is different between OS:

	# MacOS X 10.7.x
	# You need opencv is installed (macports)
	g++ -ggdb `pkg-config --cflags opencv` `pkg-config --libs opencv` header.cpp header2.cpp program.cpp -o program

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	# Ubuntu 13.04 / Mint 15
	# opencv from source because package version doesn't have nonfree modules separated (SURF/SIFT)
	# and you can have problems (install pkg-config too)
	g++ -o program program.cpp `pkg-config opencv --cflags --libs`

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;)

massive-kill for mysql sleep connections (concept)

Mmmm.... It is not a good trick.... but it could be useful: https://gist.github.com/vicendominguez/8820342

	#This is a bullshit but... i will kill all the sleep connections which sleeping time starting with 8
	for a in `echo "show processlist" |mysql --user=root --password=tete coredb |egrep 'Sleep[[:space:]]+8[[:digit:]]+' |awk '{ print $1 }'`; do echo "KILL $a" | mysql --user=root --password=tete coredb; done

view raw gistfile1.sh hosted with ❤ by GitHub

Update: Perhaps this is a better way (Mysql procedure): https://gist.github.com/datacharmer/5946490

	-- SQL
	drop procedure if exists purge_slow_queries;
	drop procedure if exists purge_idle_connections;
	drop event if exists auto_purge_slow_queries;
	drop event if exists auto_purge_idle_connections;
	delimiter //
	create procedure purge_idle_connections()
	deterministic
	begin
	declare done boolean default false;
	declare max_time int default coalesce(@max_kill_time, 200);
	declare pid bigint;
	declare c cursor for
	SELECT id
	FROM information_schema.processlist
	WHERE command in ('Sleep')
	AND time > max_time;
	declare continue handler for not found
	set done = true;
	open c;
	set @q_kill = 'KILL ?';
	prepare q_kill from @q_kill;
	PURGELOOP: loop
	fetch c into pid;
	if done then
	leave PURGELOOP;
	end if;
	set @pid = pid;
	execute q_kill using @pid;
	end loop;
	deallocate prepare q_kill;
	end//
	create procedure purge_slow_queries()
	deterministic
	begin
	declare done boolean default false;
	declare max_time int default coalesce(@max_kill_time, 200);
	declare pid bigint;
	declare c cursor for
	SELECT id
	FROM information_schema.processlist
	WHERE state in ('executing')
	AND time > max_time;
	declare continue handler for not found
	set done = true;
	open c;
	set @q_kill = 'KILL ?';
	prepare q_kill from @q_kill;
	PURGELOOP: loop
	fetch c into pid;
	if done then
	leave PURGELOOP;
	end if;
	set @pid = pid;
	execute q_kill using @pid;
	end loop;
	deallocate prepare q_kill;
	end//
	delimiter ;
	create event auto_purge_idle_connections
	on schedule every 10 second
	do call purge_idle_connections();
	create event auto_purge_slow_queries
	on schedule every 10 second
	do call purge_slow_queries();

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:S