August 30, 2014

MySQL Wish for 2013 – Better Memory Accounting

With Performance Schema improvements in MySQL 5.6 I think we’re in the good shape with insight on what is causing performance bottlenecks as well as where CPU resources are spent. (Performance Schema does not accounts CPU usage directly but it is something which can be relatively easily derived from wait and stage information). Where we’re […]

What is the largest amount of data do you store in MySQL ?

My previous poll got a great response so I thought I should continue these series. The question of the day today is How much data do your store in your largest MySQL instance ? I’m interested about single instance not the total amount of data you have in MySQL in your Sharded replicated environment. Feel […]

Impact of memory allocators on MySQL performance

MySQL server intensively uses dynamic memory allocation so a good choice of memory allocator is quite important for the proper utilization of CPU/RAM resources. Efficient memory allocator should help to improve scalability, increase throughput and keep memory footprint under the control. In this post I’m going to check impact of several memory allocators on the […]

Troubleshooting MySQL Memory Usage

One of the most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as innodb_buffer_size, key_buffer_size etc, you have reasonable amount of connections but yet MySQL takes much more memory than you would expect, causing swapping or other […]

Dynamic row format for MEMORY tables

The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.

InnoDB Flushing: a lot of memory and slow disk

You may have seen in the last couple of weekly news posts that Baron mentioned we are working on a new adaptive flushing algorithm in InnoDB. In fact, we already have three such algorithms in Percona Server (reflex, estimate, keep_average). Why do we need one more? Okay, first let me start by showing the current […]

Is there benefit from having more memory ?

My post back in April, http://www.mysqlperformanceblog.com/2010/04/08/fast-ssd-or-more-memory/, caused quite interest, especially on topic SSD vs Memory. That time I used fairy small dataset, so it caused more questions, like, should we have more then 128GB of memory? If we use fast solid state drive, should we still be looking to increase memory, or that configuration provides […]

Replication of MEMORY (HEAP) Tables

Some Applications need to store some transient data which is frequently regenerated and MEMORY table look like a very good match for this sort of tasks. Unfortunately this will bite when you will be looking to add Replication to your environment as MEMORY tables do not play well with replication.

How much memory Innodb Dictionary can take ?

The amount of memory Innodb will require for its data dictionary depends on amount of tables you have as well as number of fields and indexes. Innodb allocates this memory once table is accessed and keeps until server is shut down. In XtraDB we have an option to restrict that limit. So how much memory […]

Should I buy a Fast SSD or more memory?

While a scale-out solution has traditionally been popular for MySQL, it’s interesting to see what room we now have to scale up – cheap memory, fast storage, better power efficiency.  There certainly are a lot of options now – I’ve been meeting about a customer/week using Fusion-IO cards.  One interesting choice I’ve seen people make […]