"List me all databases that have a current replication delay of more than 10 seconds."
"Easy. Let's fetch the data from Merlin."
And that is how it started.
The mem schema has a table inventory_attributes, which decodes reported attribute names into attribute_ids:
Continue reading "Make me a MEM replication delay screen"
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Archive for the ‘Monitoring and Merlin’ Category
Make me a MEM replication delay screen
Июль 20th, 2011Getting SQL from a SPAN port
Март 18th, 2010
Recently I needed the query stream hitting a very busy master. Normally I would have been using the MySQL Proxy to collect queries, but on a very busy machine the Proxy is as much of a problem as it is part of the solution, so I chose a different approach.
I had a SPAN port configured for the master, which is Ciscospeak for a port on a switch which mirrors all traffic of one or more other ports. I had an otherwise idle machine listening to the SPAN port on a spare network card. That way it is possible to collect traffic to and from the master without any interference with the master.
On the listener box, I had tcpflow collecting data to my master (and only traffic to, not from the master):
The processor is called extract_queries and it's souce can be found below. It would be used like so:
The Source: (extract_queries.c)
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I had a SPAN port configured for the master, which is Ciscospeak for a port on a switch which mirrors all traffic of one or more other ports. I had an otherwise idle machine listening to the SPAN port on a spare network card. That way it is possible to collect traffic to and from the master without any interference with the master.
On the listener box, I had tcpflow collecting data to my master (and only traffic to, not from the master):
CODE:
tcpflow -i eth1 dst master and port 3306
These tcpflow files now need to be processed into a slow-log like format for further processing. For that I wrote a very simple processor in C after some experimentation with tcpdump and mk-query-digest had been shown as being too slow to keep up.The processor is called extract_queries and it's souce can be found below. It would be used like so:
CODE:
# mkdir flow
# cd flow
# tcpflow -i eth1 dst master and port 3306
(wait 1h)
(break)
# cd ..
# find flow -print0 | xargs -0 extract_queries -u > slow
# mysqldumpslow -s c slow > stats
# cd flow
# tcpflow -i eth1 dst master and port 3306
(wait 1h)
(break)
# cd ..
# find flow -print0 | xargs -0 extract_queries -u > slow
# mysqldumpslow -s c slow > stats
The Source: (extract_queries.c)
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