…function automatically. In cases where this is not useful, simply ignore this column. It is used to prevent wide innodb… *************************** 1. row *************************** cnt: 155187034 1 row in set …number, which is usually obtained with flexviews.get_uow_id_from_datetime() function…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… Rows_examined: 10000000 Rows_affected: 0 Rows_read: 0 # Bytes_sent: 213 Tmp_tables: 0 Tmp_disk_tables: 0 Tmp_table_sizes: 0 # InnoDB… how many rows query sends after group by, distinct and aggregate functions are removed (A) – look at number of rows examined divided by number of…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…. > 2. Not using auto_increment functionality This is right. With some > exception however. For example Innodb tables do internal full table > lock… what kind of JOIN to use so that the right number of rows are scanned and returned. SELECT * FROM articles INNER JOIN… index that has very high cardinality (as high as the number of rows in the table) are potentially very valuable if searches…
Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL
June 22, 2012 By 33 Comments
… Drop Table in Percona Server The main function that is responsible for cleaning the bufferpool…advising people to look beyond average performance numbers because they almost never really matter in … a 20M rows table: sysbench –test=oltp –oltp-table-size=20000000 –mysql-table-engine=innodb –mysql…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… hash table is accessed by using a hash function on the values of the join condition, …innodb_file_per_table=1 innodb_file_format=barracuda innodb_log_file_size=512M innodb_log_files_in_group=2 innodb…be performed because of the increase in the number of rows needed to be joined from supplier table …
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
…idea to retrieve the same number of rows on each benchmark (I noticed 100 rows on SQL and … instance, when testing the InnoDB FT index, I made sure to increase innodb_buffer_pool_size to 50…, and has different requirements for the FT functionality. So one solution may include advanced features …
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
… QUERY TIMING This is the original functionality offered by Microslow patch. The new…: 0.503016 Lock_time: 0.000048 Rows_sent: 56 Rows_examined: 1113 LOGGING OF THE…InnoDB_rec_lock_wait: 0.000000 InnoDB_queue_wait: 0.067538 # InnoDB_pages_distinct: 20 InnoDB_IO_r_ops is the counter for the number…
Post: Bug#12704861
November 20, 2011 By 1 Comment
… to the BLOB allocation. This function is also a likely culprit of InnoDB hangs that were observed when…_low(): Refactored from btr_page_alloc(). Return the number of the allocated page, or FIL_NULL if…_freed_leaves(nonfree=FALSE) to avoid leaking pages. row_build(): Correct a comment, and add a debug…
Post: MySQL Blob Compression performance benefits
January 11, 2008 By 17 Comments
… do it yourself by using COMPRESS/UNCOMPRESS functions or compressing/decompressing things on the client. …Innodb tables. With Innodb tables BLOB gets its own page (allocated outside of clustered index) if the whole row… page or at least reduce number of BLOBs on the row which need to be stored …
Post: Power of MySQL Storage Engines
March 5, 2007 By 3 Comments
… versioning and row level locks so it is question of architecture implementation details of how it would compare to Innodb storage engine… will be an extra pressure to do the fixes. While Innodb was only transactional storage engine there surely was less pressure… by and group by functions so it is implemented in rather hackish way. Same applies to checking number of rows in result set…
