> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/product-development/server-development/quality/benchmarks-and-long-running-tests/benchmark-results/select-random-ranges-and-select-random-point.md). # Select Random Ranges and Select Random Point * `select_random_ranges` (select 10 ranges with a delta as parameter) * `select_random_points` (select 100 random points) ## Findings `select_random_ranges` * A delta of 100 for the ranges gives 3 - 6% performance gain * A delta of 50 for the ranges gives 3 - 15% performance gain * A delta of 5 for the ranges gives up to 70% performance gain * A delta of 1 million shows no difference at all. `select_random_points` * We see up to 150% performance gain fetching index only * We see up to 50% performance gain fetching index and data The absolute numbers are highly RAM depended * We see an up to 250% performance difference on a 2GB system compared to a 4GB system. MariaDB and MySQL were compiled with ``` BUILD/compile-amd64-max ``` MariaDB revision was: ``` revno: 2742 committer: Igor Babaev branch nick: maria-5.2-keycache timestamp: Tue 2010-02-16 08:41:11 -0800 message: WL#86: Partitioned key cache for MyISAM. This is the base patch for the task. ``` sysbench was run with the following parameters: ``` --oltp-table-size=20000000 \ # 20 million rows. --max-requests=0 \ --mysql-table-engine=MyISAM \ --mysql-user=root \ --mysql-engine-trx=no \ --myisam-max-rows=50000000 \ --rand-seed=303 ``` and the following variable parameters ``` --num-threads=$THREADS --test=${TEST_DIR}/${SYSBENCH_TEST} ``` Configuration used for MariDB: ``` --no-defaults \ --datadir=/mnt/data/sysbench/data \ --language=./sql/share/english \ --key_buffer_size=512M \ --key_cache_partitions=32 \ # Off | 32 | 64 --max_connections=256 \ --query_cache_size=0 \ --query_cache_type=0 \ --skip-grant-tables \ --socket=/tmp/mysql.sock \ --table_open_cache=512 \ --thread_cache=512 \ --tmpdir=/mnt/data/sysbench ``` *This page is licensed: CC BY-SA / Gnu FDL* {% @marketo/form formId="4316" %}