… to start the snapshot while holding a “flush tables with read lock” and the flush operation will take some time to… works well. The tpcc database, which contains a lot of random data that doesn’t compress well showed a compression ration… will be caught by ZFS and the data will be read from the other drive in the mirror. Better availability and…
Post: Testing the Virident FlashMAX II
March 21, 2013 By 1 Comment
… standard deviation on the asynchronous random read throughput measurement is only 5.7MiB/sec. However, the overall read throughput is over 1000MiB/sec… 80%. Finally, we take a look at synchronous random read. At 256 threads, read throughput tops out at 2090MiB/sec, which is about…. For comparison, the FlashMax 1400M synchronous random read test stopped after 64 threads, reaching a synchronous random read throughput of 1345MiB/sec and a…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
… $K=rand(0,10000) // distributed by pareto distribution $C, $PAD = random_string() BEGIN INSERT INTO sbtest (id, k, c, pad) VALUES… is quite suitable for InnoDB, and in it we have random inserts into SECONDARY KEYS (k), which is not so good… = 10 #*** MyISAM Specific options key_buffer_size = 8M read_buffer_size = 1M read_rnd_buffer_size = 4M bulk_insert_buffer_size = 8M…
Post: What does Handler_read_rnd mean?
June 15, 2010 By 15 Comments
… a table based on a “fixed position,” i.e. a random-read. What this actually means varies between storage engines. For MyISAM… random read (if you think of tuples as having a natural order, which historically they did), and the other is just a read… random points in the table, although that might not actually result in random IO if the data is all in memory. Handler_read…
Post: Intel 320 SSD read performance
July 29, 2011 By 11 Comments
… these cards, and now let’s take look on a random read workload. I used a Cisco UCS C250 as base hardware… controller For simulating the workload I used sysbench’s fileio random reads. Scripts and raw results available on Launchpad. Let’s see… previous post), I think this card is very suitable for read-intensive tasks, where you can expect significant improvements. (function() { var…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
… cache) and heavy on random reads. Regardless of the file size, the difference between aligned and misaligned reads was the same and, WT… a larger files (same test I did for random reads) i.e. 8 thread random write benchmark on files totaling to 256GB. With… For the two workloads that are most relevant to databases – random reads and random writes – IO alignment on a 4-disk RAID10 with…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… I usually look for MySQL is performance in random reads and random writes. Sequential reads and writes are rarely the problem for OLTP workloads… mode Doing random read test Threads started! Time limit exceeded, exiting… Done. Operations performed: 773835 Read, 0 Write, 0 Other = 773835 Total Read 11…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… result in a lot of Random I/O. The purpose of MRR is to reduce this Random I/O and make it…, because there is no extra cost for memory access at random locations versus memory access at sequential locations. In fact there… to the storage engine and the counters Handler_read_key and Innodb_rows_read are incremented by ONE. However, when MRR is…
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
… cost for the MySQL query optimizer is a single random 4k data page read. In general, it’s a pretty good metric… about 313 sequential reads (150 million rows / 117 bytes per row / 4096 bytes per read), plus about 150 million random I/Os for the first dimension table, plus 150 million random I/Os for…
Post: Virident tachIOn: New player on Flash PCI-E cards market
June 15, 2010 By 19 Comments
… knowledge needed for FusionIO tuning. First graph is random reads, so see compare read performance As you see in 1 and 4 threads… random reads (16-64 working threads), and it is the maximal results what I’ve seen so far ( again for single card) Random write bandwidth exceeds 400MB/sec (8-16 working threads) Random read/write mix results are also impressive…
