Comments on: How network can impact MySQL Operations ? http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/ Everything about MySQL Performance Sat, 21 Nov 2009 05:23:57 -0800 http://wordpress.org/?v=2.8.4 hourly 1 By: peter http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/comment-page-1/#comment-351272 peter Tue, 02 Sep 2008 18:28:45 +0000 http://www.mysqlperformanceblog.com/?p=482#comment-351272 Pat, Good notice though in this case I mainly was speaking about switched LAN which normally is quite good with latencies. Though bunch of routers between servers can affect both latency and throughput dramatically but distance is your worse enemy in this case. I remember the customer which had performance issues and we asked him how fast is connection between 2 nodes and he told it is 1Gbit direct connection.... though he did not mention the servers actually 100 Miles from each other :) Pat,

Good notice though in this case I mainly was speaking about switched LAN which normally is quite good with latencies. Though bunch of routers between servers can affect both latency and throughput dramatically but distance is your worse enemy in this case.

I remember the customer which had performance issues and we asked him how fast is connection between 2 nodes and he told it is 1Gbit direct connection…. though he did not mention the servers actually 100 Miles from each other :)

]]> By: Pat http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/comment-page-1/#comment-351231 Pat Tue, 02 Sep 2008 14:30:41 +0000 http://www.mysqlperformanceblog.com/?p=482#comment-351231 Another thing worth pointing out is the check the latency of your network connections as well as the throughput. A high throughput high latency link can often give you worse performance (despite the high throughput) than a narrow pipe without latency problems. Especially if you app makes a lot of very fast queries, you may find network round trip takes longer than actual query execution. Another thing worth pointing out is the check the latency of your network connections as well as the throughput. A high throughput high latency link can often give you worse performance (despite the high throughput) than a narrow pipe without latency problems.

Especially if you app makes a lot of very fast queries, you may find network round trip takes longer than actual query execution.

]]> By: peter http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/comment-page-1/#comment-351068 peter Tue, 02 Sep 2008 04:46:40 +0000 http://www.mysqlperformanceblog.com/?p=482#comment-351068 Bill, Sure you want network to be working normally. I would watch error rate on switches as well as on local nodes and on local network traffic you should expect it to be close to zero. If it is not something may be faulty or miss-configured. Bill,

Sure you want network to be working normally. I would watch error rate on switches as well as on local nodes and on local network traffic you should expect it to be close to zero. If it is not something may be faulty or miss-configured.

]]> By: Bill Karwin http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/comment-page-1/#comment-350931 Bill Karwin Mon, 01 Sep 2008 17:38:35 +0000 http://www.mysqlperformanceblog.com/?p=482#comment-350931 Just to correct myself: those anecdotes apply to stranded coaxial network cables, not CAT5. Just to correct myself: those anecdotes apply to stranded coaxial network cables, not CAT5.

]]> By: Bill Karwin http://www.mysqlperformanceblog.com/2008/09/01/how-network-can-impact-mysql-operations/comment-page-1/#comment-350929 Bill Karwin Mon, 01 Sep 2008 17:28:07 +0000 http://www.mysqlperformanceblog.com/?p=482#comment-350929 Another network-level performance concern is faulty cables. When I worked in tech support for InterBase, we helped customers whose performance problems were solved when they replaced the CAT5 cables between their app server and database server. Cables contain tiny copper filaments, and these get metal fatigue if they are bent too frequently. If too many filaments are broken this way, the cable can become faulty. TCP is designed to re-try packets that aren't transmitted reliably, but that cuts down on throughput. We helped a customer who had up to 90% packet loss (which means each packet needs to be re-sent up to 10 times) because of his old, damaged cables. Another network-level performance concern is faulty cables. When I worked in tech support for InterBase, we helped customers whose performance problems were solved when they replaced the CAT5 cables between their app server and database server.

Cables contain tiny copper filaments, and these get metal fatigue if they are bent too frequently. If too many filaments are broken this way, the cable can become faulty. TCP is designed to re-try packets that aren’t transmitted reliably, but that cuts down on throughput.

We helped a customer who had up to 90% packet loss (which means each packet needs to be re-sent up to 10 times) because of his old, damaged cables.

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