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Closed 10 years ago.
I need to do some analysis of table usage within my MySQL system. Can anyone point me in the right direction on a method for identifying which table has been queried most often in a given time-period i.e. if there are 30 tables, I want to know which table is accessed most.
You should use pt-table-usage to analyze the general query log. It will out put nice information about table usage (as long as you're not using stored procedures or stored functions cause those will be missed).
Enable query logging temporarily while your application is running and review the log. It can have some performance impact, so you don't want to leave it permanently enabled.
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Closed 10 years ago.
I've been looking for a very fast and efficient way to search a database of an enormous size without using anything other than PHP and Mysql. What would be some options I could use?
The exact same way you would do it if you had 100's of rows. That's what indexes are for.
The most you can do is pay attention to the design of the tables, indexing strategy, and throw enough hardware at the solution.
If there was a silver bullet that anyone could answer in a paragraph or two here that applied universally (since you didn't give any insight to your table structure), don't you think it would already be built into MySQL?
The good news is that you will probably find that for most searches MySQL will do the job just fine even on massive databases.
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Closed 11 years ago.
I don't think innoDB could work because I need to truncate often very large tables (some GB) and i need every bit of disk space.
I have 3 tables that contain over 2 millions rows. I need to do a large number of queries for second (>50). I have only one user.
InnoDB tables area transactional and only useful where you may need to revert a commit in case something goes wrong specifically in a RDMBS environment. Based on the information you have provided which is not to none, if your only requirement is fast reads and writes I would say go with MyISAM. There are other engines too which are in-memory (definitely not a good idea with GB's of data) and have various other properties, but without more details it's hard to say if one of the others is a better fit.
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Closed 11 years ago.
thish is a general question about the "big" database player.
I want to know how these DBMS manage deleted record. In particular: does they free space and re-utilize that free space ?
Hope not to be off topic.
Thank you!
In general, they mark a deleted record as deleted, and they keep track of how much free space is available (and where), and will reuse the storage eventually (for new or updated records), but not necessarily in a timely manner.
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Closed 11 years ago.
I want to create a table that populates off of other tables and automatically updates as they are updated. How do I do that?
http://dev.mysql.com/doc/refman/5.0/en/triggers.html
Triggers can be run on inserts, updates, and deletes, so you can attach whichever ones meet your need.
Inside your trigger, you can run additional SQL statements, or work with the row that is being inserted or updated.
You'll find that triggers are very powerful, but some people don't like them because they are somewhat hidden, and people often don't check for their existence. I personally think that's a bogus argument against them since it leads to worse hacks, but be aware that you need to document them so people don't forget they are there.
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Closed 10 years ago.
When storing data in MySQL and storing the same data in SQL Server, will the size of the database differs or will it be the same for both?
Updated: What I mean exactly if we have 20 GB of disk space, and we used both SQL Server and MySQL and stored the same data exactly for example, texts, dates. All data were the same exactly in both databaes, then will the size of both be the same?
The size of the DB on disk is entirely implementation dependent, so it will likely be different. If it's not, it's just a fluke. It is also something that you shouldn't really worry about. Just buy enough disk.
It depends on many factors: block/page size, kind of data, kind of tables, type of indexes, recovery model (ms sql), data types and so on and so on.