…selection only work when the IDs for movies are distributed uniformly over the range 1..MAX…returned in a different order from what you specify in the …by a secondary index. But the result was that it created a temporary table to count…scan the `title` table first, grouping by kind_id in index order. …
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
… 9 primary key SELECTs followed by a PK UPDATE …group = 2 innodb_file_per_table = true innodb_read_io_threads = 8 innodb_write_io_threads = 8 innodb_io_capacity = 2000 max…select avg(id) from sbtest$i force key (primary) select count(*) from sbtest$i WHERE k like ‘%0%’ SysBench-0.5/lua: POINT_SELECT…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…selectivity is not good for fast inserts, but it is suitable for range selects by…_log_files_in_group = 2 innodb…max_connections = 2000 max_prepared_stmt_count=500000 max_connect_errors = 10 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 16M max…I understand from documentation …
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
… column. mysql> explain select count(*) cnt,c from gt group by c order by null limit 10; +—-+————-+——-+——+—————+——+———+——+———+—————–+ | id | select_type | table |… (0.03 sec) mysql> set global max_heap_table_size=1000000000; Query OK, …
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…from the six branches are combined with this. — AGGREGATION SQL: SELECT `word`,`md5(word)`,SUM(`count(*)`) AS `count(*)` FROM `aggregation_tmp_27656998` GROUP BY 1,2 ORDER BY…. mysql> select min(id),max(id) from words; +———+———+ | min(id) | max(id) | +———+———+ | 1 | 3088896 …
Post: Air traffic queries in InfiniDB: early alpha
November 2, 2009 By 19 Comments
…: Dynamic Rows: 2000 Avg_row_length: 0 Data_length: 0 Max_data_length: 0 Index_length: 0 Data_free: 0 Auto… records, however calculates it pretty fast. Q0: select avg(c1) from (select year,month,count(*) as c1 from ontime group by YEAR,month) t; Another bumper, on… GROUP BY Origin ORDER BY c DESC LIMIT 10; 4.96 sec Query Q4: mysql> SELECT Carrier, count(*) FROM ontime WHERE DepDelay > 10 AND YearD=2007 GROUP BY…
Comment: Speeding up GROUP BY if you want aproximate results
April 9, 2008 By 24 Comments
… max. If I cast crc32 to BINARY though, my results worked perfectly. mysql> SELECT tag, COUNT(*) AS count, crc32(tag), BINARY crc32(tag) -> FROM tags -> GROUP BY BINARY crc32(tag) -> ORDER BY count DESC -> LIMIT 10 -> ; +————+——-+————+——————-+ | tag | count | crc32(tag…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
… select count(*), min(FlightDate), max(FlightDate) from dim_dateG *************************** 1. row *************************** count(*): 8401 min(FlightDate): 1988-01-01 max(…GROUP BY Carrier ORDER BY c DESC; — Q5 SELECT t.Carrier, c, c2, c*1000/c2 as c3 FROM (SELECT Carrier, count(*) AS c from…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
…dim_date.Year IN (2009) GROUP BY 1 ORDER BY NULL ) — AGGREGATION SQL: SELECT `origin_airport_id`, SUM(`count(*)`) AS `count(*)`, SUM(`sum(AirTime)`) AS `… flight_delayed` FROM `aggregation_tmp_74082863` GROUP BY 1 –POST EXEC: DROP TABLE IF EXISTS `aggregation_tmp#74082863` ; Edit *MIN/MAX are only …
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…count(*) as total_lines from orders o join customers c using(customer_id) join order_lines ol using(order_id) group by…select customer_id, ‘> sum(total_price) total_price, ‘> sum(total_lines) total_lines ‘> from demo.dashboard_customer_sales dsc ‘> group by customer_id ‘> order by…
