… Multi Range Read) is to perform range scan as follows: * Scan the index, collect the rowids in a buffer (of @@read_rnd_buff_size bytes… ‘sweep’. the expected improvement is that the full records are read sequentially which is faster than doing random disk probing. MRR…
Comment: What exactly is read_rnd_buffer_size
January 16, 2009 By 4 Comments
[...] MySQL Performance Blog: What exactly is read_rnd_buffer_size? [...]
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
… the join_buffer_size increased to 6M, the query time was ~300s while when both the join_buffer_size and the read_rnd_buffer_size/mrr_buffer_size were set… 5.6 w/ join_buffer_size=6M & read_rnd_buffer_size=6M MariaDB 5.5 MariaDB 5.5 w/ join_buffer_size=6M & mrr_buffer_size=6M MariaDB 5.5…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
…_buffer_size – Buffer used for Key preloading, which works for MYISAM tables only. read_buffer_size, read_rnd_buffer_size – Variables used as read buffer for MyISAM tables for Full Table Scan (read_buffer) and for reading rows in sorted order (read_rnd_buffer_size). Other storage…
Comment: MySQL: what read_buffer_size value is optimal ?
September 21, 2008 By 25 Comments
… buffers to 128 kbyte? I put this in my my.cnf: key_buffer_size = 256M sort_buffer_size = 128K read_buffer_size = 128K read_rnd_buffer_size = 128K join_buffer_size = 128K myisam_sort_buffer_size… to the my.cnf): key_buffer_size 268435456 sort_buffer_size 131064 read_buffer_size 126976 read_rnd_buffer_size 126976 join_buffer_size 126976 myisam_sort_buffer_size 131072 The key_buff shows the…
Comment: What does Handler_read_rnd mean?
June 26, 2010 By 15 Comments
…_EXTRA_CACHE enables the record cache, otherwise known as read buffer, and controlled by read_buffer_size. One more odd twist to this. The original… that I do not understand, though, is how incrementing Handler_read_rnd_next is avoided on a MyISAM table without the query…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
… transaction-isolation = READ-COMMITTED max_allowed_packet = 1M max_connections=300 max_connect_errors=100 table_cache = 6000 read_rnd_buffer_size = 2M sort_buffer_size = 32k thread_cache = 16 query_cache_size = 0M thread_concurrency = 8 max_heap_table_size=200M log-output…
Comment: MySQL Connection Timeouts
January 24, 2013 By 4 Comments
…_max_sort_file_size=100G myisam_max_extra_sort_file_size=100G myisam_sort_buffer_size=30M key_buffer_size=129M read_buffer_size=64K read_rnd_buffer_size=256K sort_buffer_size=256K #*** INNODB Specific options *** innodb_data_home_dir=”D:/work/MySQL Datafiles/” innodb_additional_mem_pool_size…
Comment: MySQL File System Fragmentation Benchmarks
July 9, 2008 By 28 Comments
…_max_sort_file_size=100G myisam_max_extra_sort_file_size=100G myisam_sort_buffer_size=185M key_buffer_size=157M read_buffer_size=64K read_rnd_buffer_size=256K sort_buffer_size=256K #*** INNODB Specific options *** innodb_additional_mem_pool_size=20M…
Comment: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 100 Comments
…_buffer = 384M max_allowed_packet = 256M table_cache = 512M sort_buffer_size = 2M read_buffer_size = 2M read_rnd_buffer_size = 1M myisam_sort_buffer_size = 64M thread_cache_size = 80 query_cache_size…_len=3 tmpdir = /opt/ key_buffer_size=256M connect_timeout=180 wait_timeout=360 tmp_table_size=851443712 Can you pl help me…
