… in many cases you can use result overload to make MySQL to consume so much memory so it will swap badly until it…. General Overload As MySQL does not have much of resource utilization control you can simply run heavy queries to get MySQL Server barely… of the worse because they would both overload IO system and wipe off both MySQL and OS caches which can cause other…
Post: MySQL for Hosting Providers - how do they manage ?
November 28, 2008 By 15 Comments
… over a year ago about 10+ ways to crash or overload MySQL and since that people have come to me and suggested… @a13:=repeat(“a”,1000000); select sleep(1); … Causes MySQL to “leak” 1MB of memory per second with no apparent good reason – no…_mask=0x201d2, order=0, oomkilladj=0 Call Trace: [] out_of_memory+0x8e/0x2f5 [] __alloc_pages+0×245/0x2ce [] __do_page_cache_readahead…
Post: Thoughts on MySQL Replication
July 7, 2006 By 18 Comments
… Memory is much faster than disk and you generally want to have data you’re accessing to be cached in memory by MySQL… replication ? – Small database size. Small meaning working set fits in memory. This reduces waste of storage, removes problem with cache duplication… want to structure replication with median servers to avoid master overload in such case. – No long queries – As I already wrote…
Post: MySQL Prepared Statements
August 2, 2006 By 21 Comments
… consumed time but also required extra memory consumption both on server and client. So in MySQL 4.1 Prepared statement came. Do…. Do not forget to close prepared statements – Many memory leaks reported in MySQL Server turned out to be prepare statements or cursors… statements can be open at the same time to avoid overload. Check execution rate You can take a look at Com…
Post: Are PHP persistent connections evil ?
November 12, 2006 By 32 Comments
…. Threads also take memory resources both on kernel and MySQL size but most problems seems to happen in case of “overload“. In case… tables or having other significant memory requirements you may well out of memory and get crash or have MySQL starting to swap aggressively… connections were added to PHP during times of MySQL 3.22/3.23 when MySQL was simple enough so you could recycle…
Comment: Falcon Storage Engine Design Review
January 13, 2007 By 19 Comments
… care about how much memory in a overloaded sitation which the database might use. Given that the internal memory caches is optimized or has code that optimizes itself during runtime. As a compare is the memory options in regular mysql…, is falcon now the new official transactional db storage in mysql since innodb got bought my oracle? And what happend to…
Post: When to use Hardware upgrade instead of Software Optimization
December 5, 2008 By 5 Comments
… Say you have 10 servers one of them is overloaded and 8 are almost idle. In this case… and it also can be done easily. Is MySQL, Queries, Architecture optimized well enough ? Do not advice… what needs to be done (gettings SSD, upgrading memory, upgrading CPUs). There are number of balancing questions…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…The great things about objects is you can easily overload > methods and get debugging and profiling tools,…traditional database background. > Things are different with MySQL. Good design will help dictate how many… columns will take up tremendous amounts of memory and disk. Because indexes are fast by…
Post: Speeding up GROUP BY if you want aproximate results
March 7, 2008 By 24 Comments
… this query ran for over half an hour badly overloaded server and I had to kill it in the… Of course it would be possible to allocate more memory to the temporary table or switch to filesort method…a hash of the page instead of page itself: mysql> select sum(cnt) from (select count(*) cnt from …
Post: Why you don't want to shard.
August 6, 2009 By 34 Comments
…reasons: Very large working set – The amount of memory you require to keep your frequently accessed data…busy tables, and move them onto their own MySQL server. Partition-by-function keeps the …far exceed average users and some servers are overloaded while others are not.(Tip: There are a…
