Hello Chris, Can pls you share the below command output...
> SHOW STATUS LIKE 'Threads%'; > SELECT @@thread_cache_size, @@net_buffer_length, @@max_allowed_packet; What about the limits.conf config on operating system level? -- WB, MySQL Oracle ACE > Em 07/12/2014, às 20:03, "Chris Knipe" <sav...@savage.za.org> escreveu: > > FYI - just an example... > > mysql> SELECT VERSION(); > ERROR 2006 (HY000): MySQL server has gone away > No connection. Trying to reconnect... > Connection id: 203720459 > Current database: NNTP > > +-----------------------------+ > | VERSION() | > +-----------------------------+ > | 5.5.38-0ubuntu0.12.04.1-log | > +-----------------------------+ > 1 row in set (33.94 sec) > > > mysql> SELECT VERSION(); > +-----------------------------+ > | VERSION() | > +-----------------------------+ > | 5.5.38-0ubuntu0.12.04.1-log | > +-----------------------------+ > 1 row in set (0.00 sec) > > > This is from the mysql client running on the same host as the mysql server, > connected to localhost via TCP. Current connections to the DB was at about > 200 out of 500 > > -- > Chris. > > > > -----Original Message----- > From: Chris Knipe [mailto:sav...@savage.za.org] > Sent: Sunday, December 07, 2014 11:34 PM > To: 'mysql@lists.mysql.com' > Subject: mysql strangeness... > > Hi, > > I have a "not so" busy MySQL server (+- 150 Selects/sec, 180 Deletes/Sec, > 320 Updates/Sec, 90 Inserts/Sec and 200 Replace/Sec), max 512 concurrent > connections. > > The server is running on a Dell R720 with 64GB Ram, Xeon E5-2620. Data is > on a 4 x 3TB (RAID10) SATA3 array, and binlogs on a 4 x 600GB (RAID10) SSD > array. MySQL 5.5.38 > > Up to a while ago (few days / week), everything was running absolutely fine. > Lately however, I have noticed more and more times that I am hitting my max > connection limits. Standard tools like mysql-tuner (which took more than an > hour to run because of slow connections to MySQL), tuning-primer, innotop, > etc. all shows that the configured variables are within normal parameters, > and MySQL is also not under *any* IO load what so ever. I'd say 99% of all > tables are InnoDB, and even the one single Memory table that I have, seems > to be running slow queries :-( I'm also seeing a lot of "connection reset > by peer" network related errors. > > What I am seeing, is that even when there are only like 300 or so > connections established to the server, even the mysql (command utility) > running on the localhost, takes MINUTES to establish a connection to the > mysql server - however, once the connection IS established, queries execute > absolutely fine and within seconds. It's just the initial establishment of > the connection to mysql which is taking forever. The process list shows 99% > of all the active connections in a "READING FROM NET" state (unauthenticated > users). Skip-name-resolve and all those things are disabled, and tcpdumps > also confirmed that mysql is in fact NOT doing DNS lookups. > > The server IMHO is under no significant load at all (dedicated mysql > system), and there's only +- 5Mbps of traffic on the 1Gbps interface in the > server. All in all, graphs indicate 750/800 QPS with about 30% reads, and > 70% writes. > > Can anyone perhaps suggest some things to look into here? I'm pretty sure > that the problem is with the initial establishment of the TCP connection to > mysql, rather than it being a mysql issue related to queries and what not. > Telneting to the mysql socket, I do get the initial greeting from the server > virtually instantaneous like it should be. So the only thing that I can > think of is that something is whacked in terms of authenticating users? > > Box is firewalled, only authorised hosts are permitted to connect, all users > are authenticating by password and IP (%) > > -- > Chris. > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/mysql >
