I recently wanted to check all tables’ current AUTO_INCREMENT value (if any) for a database dump structure. I wasn’t sure if a tables’ Data Definition Language (DDL) statement contained the current AUTO_INCREMENT value or not. So after I loaded the dump file, I learned of a query to use and find out…
The Newsletter for PHP and MySQL Developers
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[Read more]The following is a short HOWTO about deployment and use of Benchmark-kit (BMK-kit). The main idea of this kit is to simplify your life in running various MySQL benchmark workloads with less blood and minimal potential errors.
Generally as simple as the following :
$ bash /BMK/sb_exec/sb11-Prepare_50M_8tab-InnoDB.sh 32 # prepare data $ for users in 1 2 4 8 16 32 64 128 256 512 1024 2048 do # run OLTP_RW for 5min each load level.. bash /BMK/sb_exec/sb11-OLTP_RW_50M_8tab-uniform-ps-trx.sh $users 300 sleep 15 done
the latest public online version of the following HOWTO is always available from here : http://dimitrik.free.fr/blog/posts/mysql-perf-bmk-kit.html
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I could barely stuff this week’s OpenLampTech issue #31 into the email client to send out. It is that full!
The Newsletter for PHP and MySQL Developers
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In this week’s OpenLampTech issue #31, we are covering articles on:
Original and curated content. PHP, MySQL, and the LAMP stack. All in one place. Every week. …
[Read more]Full table scans can be problematic for performance. Certainly if the scanned tables are large. The worst case is when full table scans are involved in joins and particularly when the scanned table is not the first one (this was dramatic before MySQL 8.0 as Block Nested Loop was used) !
A full table scans means that MySQL was not able to use an index (no index or no filters using it).
Effects
When Full Table Scans happen (depending of the size of course), a lot of data gets pulled into the Buffer Pool and maybe other important data from the working set is pulled out. Most of the time that new data in the Buffer Pool might even not be required by the application, what a waste of resources !
You then understand that another side effect of Full Table Scans is the increase of I/O operations.
The most noticeable symptoms of Full Table Scans are:
Who dares diagram a system and process as complex as InnoDB page flushing? I do.
Who dares diagram a system and process as complex as InnoDB page flushing? I do.
Who dares diagram a system and process as complex as InnoDB page flushing? I do.
We don’t always need all rows from the table as part of the final results set. You can use one (or more) of the comparison operators to filter the rows with a WHERE clause conditional. In this post, we are looking at the equality comparison operator (=)…
The Newsletter for PHP and MySQL Developers
Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.
Image by kalhh from …
[Read more]I’m back again this week with your MySQL, PHP, and LAMP stack media outlet source. There are plenty of great reads in this week’s OpenLampTech newsletter. Enjoy and please share the publication.
The Newsletter for PHP and MySQL Developers
Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.
There is something for everyone in OpenLampTech issue #30. We have articles covering:
Don’t …
[Read more]
Is SQL, or Structured Query Language, a programming language?
That’s a great question! A question that many answer with
emphasis: “No, SQL is not a programming language!” There
are some who answer yes; and they usually qualify that answer
with something like: “SQL is a programming language designed
to communicate with relational databases.”
It strikes me that those saying “yes” are saying that SQL is only a collection of interface methods to read from and write to a database engine. Those saying SQL is not a programming language often qualify that a programming language must have conditional logic and iterative structures, which don’t exist in SQL.
There’s a third group that are fence sitters. They decline to say whether SQL is a programming language, but they also say individuals who only write SQL aren’t programmers. That’s a bit harsh from my perspective.
Before …
[Read more]
