…from standard input, and outputs the SQL_API statements representing the original SQL statements. Each MV name will be taken from the table…from a monthly summary. The monthly summary is actually another…column `mview$pk` which is an auto_increment BIGINT surrogate key for the table…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 12 Comments
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…TABLE By temporarily dropping secondary indexes from the new table before copying the data, and then recreating them later, ALTER TABLE…TABLE t ADD COLUMN…table” part will not be affected by a slow tmpdir, but rebuilding the indexes will obviously take longer. Another…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
…data sets and queries. Another advantage is that …table `ontime_fact` is created by joining the newly constructed dimension table tables to the staging tables, omitting the dimension columns from…rebooted between tests. A SQL script was fed …-Query adds parallelism when “subqueries in the from clause”…
Comment: When should you store serialized objects in the database?
January 22, 2010 By 42 Comments
…never going to need to be searched using SQL queries, then you may want to consider …is if you add or remove a setting, you don’t have to add/remove a column from your …database table with one other column indexed to map to another table. For example, have a table of accounts, make another table …
Post: Redundant index is not always bad
August 28, 2007 By 7 Comments
… first part of another. I’m speaking about BTREE indexes, for example, KEY (A), and KEY (A,B). From SQL point of view…, which store all needed columns in the index, and there is no need to read row data from the table. So – we can extend index `state_id_idx` (`state_id`) by two columns: ALTER TABLE userinfo DROP KEY state_id, ADD…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… parallelization, so ETL jobs written to rely on SQL tend to get really bogged down. In …to get the totals you add them. Did this gain us anything? We dropped one column, and we just …Aside from star schemas, another tactic I see people try a lot is to build “flexible schemas” with tables that …
Post: Using Flexviews - part one, introduction to materialized views
March 23, 2011 By 2 Comments
…SQL query, and what we normally think of as a result set is really a virtual table. It has columns… from relational algebra, upon which SQL is built. All SQL …tables via CTAS and have them all be transactionally consistent with one another… the table will be considerably cheaper You can add indexes…
Post: Intro to OLAP
July 12, 2010 By 9 Comments
…and the kind of SQL which a ROLAP… which is really just another name for multidimensional …columns which are joined to the dimension tables, such as product_id and customer_id. These are often defined as foreign keys from…table which includes the two different order statuses. Such a dimension would add…
Post: Talking MySQL to Sphinx
April 19, 2009 By 4 Comments
…a support for MySQL wire protocol and SphinxQL – SQL-like language to query Sphinx indexes. This …see Sphinx adds couple of extra columns to result set even if you have not asked it. Another thing… table which will make Sphinx much faster and few others. The true gain from Sphinx however comes from…
Post: EXPLAIN EXTENDED can tell you all kinds of interesting things
June 15, 2010 By 7 Comments
…SQL optimizer. EXPLAIN EXTENDED adds…tables listed. Taking a look at the Extra column we see that MySQL mentions ‘const’ tables. A ‘const’ table is a table…table will be read. This is because these tables contain no indexes. There is another…
