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visits member for 2 years, 11 months
seen Dec 18 at 23:11

Dec
18
comment Optimizing “Removing duplicates” thread state
If the intermediate state results in a lot of rows with no index, then MySQL would have to do a full table scan to remove duplicates, which would take a long time. I am having the same issue and I will need to see if adding an index to a table would help, or if I have to rewrite my query in some way.
Nov
28
awarded  Popular Question
Oct
13
awarded  Famous Question
Aug
24
comment How large should be mysql innodb_buffer_pool_size?
Some people suggest that IOs over 200 are too much unless you have an SSD with much faster write speed. I don't know if they are correct. chriscalender.com/iops-innodb_io_capacity-and-the-innodb-plugin
Aug
15
revised Subqueries run very fast individually, but when joined are very slow
added an update about the query's speed with a larger number of rows
Aug
8
awarded  Notable Question
Jul
28
comment Are individual queries faster than joins?
I agree with everything Jon is saying. If you are going to do multiple selects then you can maintain consistency in MySQL by using table or row locks, which I'm sure every major RDBMS can do. In the ORM I'm working on now, there are builder objects that wire things like customer and invoice. If I'm looking at a customer view, it will use a query that gets invoices for that customer using invoices::getBy('customer_id',$cust_id) or something like that. The executed query would be a simple join.
Apr
24
awarded  Tumbleweed
Apr
17
comment What is the best way to manage user access to MySQL via PHP?
As Leonard has said, you should limit the types of queries different users can make. Don't give write access, or ALTER TABLE access, to users that only need to read data.
Apr
17
asked MySQL - How to grant read access to all tables, write access to a few, to one user for multiple databases?
Feb
11
comment Preordering the table by a specified column
I couldn't figure out why my InnoDB table was not ordered by its primary key until I saw this answer. I thought it was called a "composite index" rather than "clustered index," but either way I now see that the table is ordered by my 2nd column, which is part of such an index (along with column 3).
Jan
30
awarded  Yearling
Jan
9
awarded  Popular Question
Jul
23
comment How can I speed up “show columns” on MySQL?
+1 for putting [mysqld] there. It might be obvious to many that this setting would go under mysqld, but may not be obvious for those who would ask this question. By the way, this sped up SELECT COUNT(*) on one of my information_schema tables to 6 seconds from over a minute. Still slow, but a huge improvement.
Jul
3
comment Mysql Innodb: InnoDB: ERROR: the age of the last checkpoint is InnoDB: which exceeds the log group capacity
Wouldn't it be advisable to copy the ib_logfile* to another location for backup before deleting them?
Jun
5
revised Why would increase in innodb_buffer_pool_size slow down MySQL?
added results of shell commands while mysql process is running
Jun
4
comment Why would increase in innodb_buffer_pool_size slow down MySQL?
@RolandoMySQLDBA I added the query results to the question. I can rerun the shell commands during the process tonight.
Jun
4
revised Why would increase in innodb_buffer_pool_size slow down MySQL?
added results of suggested queries
Jun
4
comment Why would increase in innodb_buffer_pool_size slow down MySQL?
@RolandoMySQLDBA I added them but those were run NOT during the process in question. I can give you the output while the process is running if you want.
Jun
4
revised Why would increase in innodb_buffer_pool_size slow down MySQL?
added details on the queries being performed and some shell command output