… removed. That’s why there is special distribution, which is better, but to other extreme – it is skewed to very small percentage of rows, which makes this distribution good to test cache, but it is hard to… a parameter θ (theta), which defines how skewed the distribution is. A physical sense of this parameter, if to apply to…
Post: Testing Intel SSD 520
May 1, 2012 By 7 Comments
… almost stable 370 MiB/sec throughput, with some strange small periodic drops. To better understand response time ranges, we need to switch… performance SATA is getting closer to level of PCIe cards. Of course PCIe still provides better numbers, but the question is how much… are highly underutilized. With the performance variance we see it is a good question how does it affect MySQL performance, and…
Post: Testing STEC SSD MACH16 200GB SLC
April 25, 2012 By 7 Comments
…/sec, but every 20 min, there is small drop to 87 MiB/sec, which I guess is related to internal garbage collector activity…: Very stable throughput on line 222 MiB/sec To understand better what kind of response time we should expect, I ran… as part of consulting work for STEC, but this post is totally independent and fully reflects our opinion. Follow @VadimTk !function…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… the same page multiple times. Consider if you have a small buffer pool and a very large number of rows from… be increased appropriately for the best possible performance gain. This is not entirely visible in the manual either for MariaDB or… Join, but for now it looks like Nested Loop Join is a much better general purpose join algorithm.
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… were responsible for memory allocation. If you figured out it is related to connections and identified application which causes excessive memory… if you close connection. In Percona Server you can do better as you can query temporary tables too: mysql> select sum… common thing about memory leaks is because it is memory which is allocated and forgotten about, unless it is very small blocks, it should be…
Post: Small things are better
October 8, 2006 By 15 Comments
… to have your recovery plan this kind failures. This is one thing you better to have backups for. Backups however take time…. With MySQL and blocking ALTER TABLE there is yet another reason to keep tables small, so you do not have to use… tables. Current data size is small enough so even single table would not be big problem but it is much easier to write…
Post: READ-COMMITED vs REPETABLE-READ in tpcc-like load
February 11, 2010 By 6 Comments
Question what is better isolation level is poping up again and again. Recently it was discussed in … for InnoDB . Serge in his post explains why READ COMMITED is better for TPCC load, so why don’t we take tpcc… more preferable, however difference is very small. For 300w: I would say both modes are even there, there is no winner for me…
Post: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 27 Comments
… type, but is it really necessary (from performance standpoint)? In this post I’d like to present a small benchmark which shows… about this table before we get to results – this is rather small table which fits in memory in all cases (and dictionary… is 30% lower. Also note the times themselves – traversing about same amount of rows full table scan performs about 25 times better…
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
… think for such CPU bound benchmarks, an old computer is better, if there are small differences, they’ll be easier to observe. I… graph is that the expected correspondence between the time for the queries and the number of sort merge passes. For the small….1.41-3ubuntu12.6-log P.S.: Gnumerics for graphs is so much better than OpenOffice Calc.
Post: Should I buy a Fast SSD or more memory?
April 8, 2010 By 10 Comments
… establish a baseline. The Y axis is transactions/second (more is better), the X axis is the size of innodb_buffer_pool_size… are all relatively small. There are already appliances on the market which use 8 Intel SSD devices). Is a 2x or… small percentage – but in other cases it can be considerably higher. If you don’t know what your working set is…
