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Post: SQL Injection Questions Followup
July 26, 2012 By 2 Comments
…(“,”, array_fill(0, count($params), “?”)); $sql = “SELECT * FROM Bugs WHERE bug_id IN ($placeholders)”; $stmt = $pdo->prepare($sql); $stmt->execute($params); Radu M… customer who uses dynamic SQL in stored procedures extensively. They found that it was awkward because of the limits of the procedure…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… that it parses by running the SELECT portion, adding LIMIT 0 to the SELECT part of the query. convert….view. mysql> select flexviews.get_sql( -> flexviews.get_id(‘demo’,'dashboard_customer_sales’)) -> as ‘SQL‘ \G *************************** 1. row *************************** SQL: SELECT NULL as …
Post: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 28, 2007 By 57 Comments
…: mysql> SELECT SQL_NO_CACHE SQL_CALC_FOUND_ROWS * FROM count_test WHERE b = 555 ORDER BY c LIMIT 5; Results with SQL_CALC_FOUND… EXPLAINs: mysql> explain SELECT SQL_CALC_FOUND_ROWS * FROM count_test WHERE b = 999 ORDER BY c LIMIT 5; +—-+————-+————+——+—————+——+———+——-+——-+————-+ | id | select_type | table | type…
Post: Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
… of the distributed reduction discussed above. If you have any limitation in resources in a cluster (cpu, memory, disk, power,etc…, and a WHERE clause that uses an IN clause: — INPUT SQL: select origin_airport_id, count(*), sum(AirTime), sum(DepDelay), sum(DepDelay….Year IN (2009) GROUP BY 1 ORDER BY NULL ) — AGGREGATION SQL: SELECT `origin_airport_id`, SUM(`count(*)`) AS `count(*)`, SUM(`sum(AirTime…
Post: Updated msl (microslow) patch, installation walk-through!
April 20, 2008 By 17 Comments
… file sql/sql_cache.cc patching file sql/sql_class.cc patching file sql/sql_class.h patching file sql/sql_parse.cc patching file sql/sql_select.cc patching file sql/sql… both SET SESSION and SET GLOBAL. log_slow_rate_limit=# Rate limit statement writes to slow log to only those from every…
Post: MySQL Server Variables - SQL layer or Storage Engine specific.
June 8, 2006 By 14 Comments
… per single insert statement. concurrent_insert – Enables concurrent insert (while Selects are running) for MyISAM storage engine. Other Storage engine ether… but tables will be badly corrupted on crash. delayed_insert_limit, delayed_insert_timeout, delayed_queue_size Delayed inserts configuration. Technically… Innodb. Some SQL level items as Query Cache also could use this feature. low_priority_updates If enabled selects will get higher…
Post: MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown
March 14, 2013 By 2 Comments
…) optimizer issue: a “SELECT *” taking half the time to execute than the same “SELECT one_indexed_column” query …With ICP, the actual number of rows read at SQL layer is actually very different from the “rows”… edge case — but I would call it a limitation of the current query planner. However I would…
Post: MySQL extensions for hosting
April 24, 2008 By 11 Comments
… for only a few customers simply because their skills in SQL are limited. The real life customers generate very uneven load – some…: 20 Busy_time: 1 Rows_fetched: 7861 Rows_updated: 240 Select_commands: 1759 Update_commands: 254 Other_commands: 85 Commit_transactions… see their own statistics only information_schema support to allow SELECT query transformations, joins and better filtering for the statistics Also…
Comment: How To Test Your Upgrades - pt-upgrade
July 24, 2012 By 7 Comments
….1.100,u=perc,p=perc,P=3306 –convert-to-select –limit 100% –temp-database pt_upgrade –clear-warnings-table pt_upgrade…,warnings –compare-results-method rows, Should I use –convert-to-select in the above pt-upgrade query? I have same set… have those warning or errors so we can rewrite the sql queries if required? Thanks for your time.
