…table. It has columns and rows, just like a database table, but it is temporary in nature, usually existing only in…table. When…indexes to the MV. Since the data is already joined together and pre-aggregated, CPU and memory usage may be reduced compared…same point in time.  There are two…
Post: Dynamic row format for MEMORY tables
September 6, 2011 By 5 Comments
…same for both row formats. (Speaking very strictly, the VM Peak value is not comparable due to slightly different number of rows inserted). In…tables are still used for temporary tables where the MEMORY tables with dynamic row format could be used…
Post: Redundant index is not always bad
August 28, 2007 By 7 Comments
…row data from the table. So – we can extend index `state_id_idx` (`state_id`) by two columns: ALTER TABLE…comparing with non-convering index. But if run the test for Q1 we have: 25.40 q/s, that in…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…used at the time of this post are 5.5.30 and 5.6.10, each of which are GA when…row in set (0.00 sec) Now compare…rows in set (0.00 sec) mysql> select sq.*, pages / ((@@innodb_buffer_pool_size / 16384)) * 100 pct_buffer_pool from ( select table_name, index…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
…index prefix compression prevents one from using a binary search on a B-tree node. We could not compare…when this should be helpful the most. Q3: Does Innodb secondary Indexes trees are allocated in two extents same as primary key tree or stored in…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
…row-by-row updates. But you would still have to update the RT index as data changes, using application code. Since RT indexes are in…table…same hardware, I got results that are least comparable…when I present the popular Percona Training in…
Post: Paul McCullagh answers your questions about PBXT
November 20, 2009 By 2 Comments
…use case for the PBXT engine, and how does it compare in performance? Â When would I use…uses 16K pages for the index data and (approximately) 32K pages for the table data. Both sizes can be set using…in turn tries to acquire LOCK_plugin! Unfortunately a thread hangs if it tries to acquire the same…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…two portions in…same as “reservation” – before falling back to complex wait using sync_array Innodb tries to “yield” to OS hoping when…, compared…index read mysql tables in use…in row lock hash table is number of row lock structures allocated by all transactions. Note not same as number of locked rows…
Post: MySQL Performance - eliminating ORDER BY function
October 17, 2007 By 6 Comments
…using functions when comparing constants or order by. Ie use indexed_col=N is good. function(indexed…table: tst type: ref possible_keys: i key: i key_len: 5 ref: const rows: 10 Extra: Using where; Using filesort 1 row in…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
…when a battery-backed disk controller write-back cache does the same thing. PZ: First Indeed writes are slower with Flash disks compared…rows in contiguous blocks of 64 pages == 1 MB. Then a full table scan would be fast. Maybe the table…
