…MySQL server. Queries are logged with timing information, and in the case of Percona Server, a great deal of additional performance… full round-trip time, including network delay, as seen by the application server. … time the queries and write a query log. I suggest writing out something in …
Post: Thoughts on MySQL Replication
July 7, 2006 By 18 Comments
… read intensive envinronments. Write scaling however can be real problem. Not moderate increase of write ratio can dramatically reduce performance but you also…” performance will drop 4 times if write load growth by only 50%. – Delays in replication MySQL replication is fast which means in average delay is…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…disk tables and HEAP for in memory tables. So first MySQL versions did not bother naming variables with storage engines … delay_key_write Delay updating indexes for MyISAM tables. Good for performance but tables will be badly corrupted on crash. delayed_insert_limit, delayed_insert_timeout, delayed…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
… worst case for performance. Optimal mathematical performance requires operations on … materialized views. While writing Flexviews, I learned …but right now only MySQL storage nodes are supported… flight_delayed`=`sum(DepDelay >= 0) flight_delayed` + VALUES(`sum(DepDelay >= 0) flight_delayed`) …
Post: Why delayed flushing can result in less work
December 9, 2009 By 5 Comments
… the overall number of I/O operations performed. Smoothing out the workload can cause more …write combining. In some workloads, the same rows could be updated many, many times — so delaying and permitting write… side effect such as mutex contention inside MySQL or InnoDB. So whether this matters for …
Post: How does MySQL Replication really work?
January 9, 2013 By 9 Comments
… decided to write one now. Of course, there are many aspects of MySQL replication, but…. There could be a network delay, causing a steady delay of few hundred milliseconds,…performance, not writes. Let me explain this further. Assume you have a RAID10 with a bunch of disks and write-back cache. Writes…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
… key writes which kill performance. The problem with writes is OS can delay writes only for fixed amount of time and when it has to perform… written. So I filled bug on this. So what was performance mysql> select count(*) cnt,c from gt group by c order… temporary tables performance to avoid OS writes OS Write cache is not as efficient as I would hope, at least on Linux Performance of…
Post: Implementing efficient counters with MySQL
July 1, 2007 By 16 Comments
…you can’t easily tell it to perform certain action (ie write back to the database) when object…use existing solutions you can use memcache + another mysql instance (or simply the database which is not…counters while being very efficient. By doing these delayed updates you can not only reduce number of…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…engine or database About the cluster For best performance, there should be an even data distribution … data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘ontime_fact’…timer-based innodb-thread-sleep-delay=0 innodb-use-sys-stats-table innodb-write-io-threads=4 …
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… data to their own clients, with no delays. Finally, the analysis is usually multi-dimensional.Â… for the initial insertion, because you can write CSV files with any programming language. Naturally… schemas. The problem is that MySQL doesn’t tend to perform well on a data warehousing workload…
