…actually is and what benefits it brings. Multi Range Read With traditional secondary index lookups, if the …_orderdate >= ’1993-08-01′ and o_orderdate < date_add( ’1993-08-01′ ,interval ’3′ month) …as well. But this works only with joins and specifically with Block Access Join Algorithms. So I am not …
Post: How adding another table to JOIN can improve performance ?
August 1, 2008 By 12 Comments
… suboptimal execution for large ranges. Lets take a look at very typical reporting query which queries data for date range for multiple of… first key part is used. Let us now replace the range with IN list in this query: mysql> explain select sum(events… sec. The query with BETWEEN range replaced with IN list was instant 0.00 sec same as the query using join with day list table…
Post: Joining on range? Wrong!
May 17, 2010 By 10 Comments
… to paint it.” — Dr. Emmett Brown I populated these tables with enough data to serve our purpose. Our hypothetical sales query… the date range. A very inefficient approach! MySQL was unable to optimize those simple conditions to match both product id and date range by index and read only the relevant rows. This affects joins only. When you use a range condition on…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… to the ad-by-day table. If you query date ranges most of the time, you should define the primary key… when you have a lot of joins between fact and dimension tables, and so on. With careful tweaking, many of these… scenes from the name-value tables in a complex query with many joins. I have never seen this approach scale well. Use…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
… dimension columns from the projection, instead replacing them with the dimension keys: select dim_date.date_id, origin.airport_id as origin_airport… join dim_date using (date_id) WHERE DepDelay>10 GROUP BY Year) t JOIN (select Year, count(*) as c2 from ontime_fact join dim_date using (date… the size of the date range: — Q8.0 SELECT dest.CityName, COUNT( DISTINCT origin.CityName) from ontime_fact JOIN dim_airport dest on…
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 93 Comments
…it to use index – in this case index range scan will be started and query execution stopped…on many different columns, with worse then perfect selectivity. Various social networking and dating sites are perfect example… possible to use index to do ORDER BY with JOIN MySQL still will not be able to use…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… auto_inc; Compare that to Percona Server with log_slow_verbosity=full: # Time: 111229 3:…# QC_Hit: No Full_scan: Yes Full_join: No Tmp_table: No Tmp_table_on_… 26.23M rss, 62.49M vsz # Current date: Thu Dec 29 07:09:32 2011 #… of the time lies in the range >= 10ms and < 100ms. The “Tables” section …
Post: Analyzing air traffic performance with InfoBright and MonetDB
October 2, 2009 By 50 Comments
… NULL, `DayOfWeek` tinyint(4) DEFAULT NULL, `FlightDate` date DEFAULT NULL, `UniqueCarrier` char(7) DEFAULT NULL, …JOIN (select YEARD,count(*) as c2 from ontime GROUP BY YEARD) t2 ON (t.YEARD=t2.YEARD) with… to crunch. For query Q8 (1year range) traditional transactional oriented stored engine took …
Comment: Joining on range? Wrong!
May 18, 2010 By 10 Comments
… be possible to `trick` mysql. Basically you create a date table with a date_id (surrogate key) in it. You place that id instead of the datefield and you should be able to join properly on the date table where you can use the range function. Yes it is more…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…commanual datadirblogpercona.commanual date_formatblogpercona.commanual datetime…interactive_timeoutblogpercona.commanual join_buffer_sizeblogpercona….range_joinblogpercona.commanual Select_rangeblogpercona.commanual Select_range…commanual updatable_views_with_limitblogpercona.commanual …
