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Re: Why is Postgres so much better than MySQL? -- was Re: MySQL -- was mysql backup quesiton



 > [hidden email] wrote: 
>> This is a very important discussion, IMHO so, and I know I'm at least 
>> partially responsible, lets try to keep it polite. OK? 
>> 
> As always. 
>>> On Sat, 2008-01-05 at 23:43 -0500, Mark Woodward wrote: 
>>> ... 
>>> 
>>>> Like any high performance product, if you never push it or never 
>>>> compare 
>>>> it, you won't notice the difference. A Porsche doesn't feel much 
>>>> different than a Volkswagen sitting in a garage. 
>>>> 
>>>> MySQL does not support SQL well enough to create really efficient 
>>>> queries. MySQL's query analyzer does not do a very good job at mapping 
>>>> a 
>>>> query to an access plan. When the amount of data you wish to access is 
>>>> negligible these things are also negligible.  When the amount of data 
>>>> is 
>>>> non-trivial, MySQL is catastrophic. 
>>>> 
>>>> After that, MySQL's performance in a high volume site is abysmal. As 
>>>> long as it is read-only, you are fine. If you start adding table 
>>>> updates, inserts, or deletes MySQL's performance profile crumbles. Why 
>>>> do you think you see so many "Can't access database" messages from 
>>>> MySQL 
>>>> sites that have been slashdotted? 
>>>> 
>>> It never cease to amaze me about the bad claims of MySQL performance. I 
>>> work at a company that typically has 30,000 - 50,000 simultaneous users 
>>> on their site in a social network setting. High reads, high writes, on 
>>> MySQL 4.x. Performance is great. 
>>> 
>> 
>> What does that translate to in regards to hits? What kinds of queries do 
>> you use? Do you use MySQL as the session manager? 
>> 
> The code to support this application was badly written. It queries the 
> database more often than it needs to. The code was never intended to 
> support this level of traffic. MySQL is currently being used to manage 
> sessions, though moving forward we wish to move it out of that role. 


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