Reducing run times by breaking a problem into parts that can be completed by separate execution paths simultaneously.

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Mathematical or Computing Alternatives for MySQL Combination Queries operating toward their Performance Limit

We regularly run a contest that is becoming quite popular. In the contest, we need to select the combinations of contestants from 8 groups whose cost is under a threshold, and who combined have the ...
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Are the following statements concerning sys.dm_exec_requests true?

Parallel plans mean that cpu_time can be greater than total_elapsed time. Therefore, per-query wait time is not possible to determine accurately from DMVs on servers with more than one CPU thread. ...
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Parallel insert in db2

I am trying to import from 8 files and insert into a single table in db2. I am running 8 .sql files that will do the task, but only one of them actually seem to be running and inserting into table. ...
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Oracle parallel query: finding out which Producer a Consumer is waiting for

One of our materialized view refresh's (part of a daily ETL routine) was hanging today; it usually completes within 5 minutes, but this time, I had to kill it after 23 hours. V$SESSION contained this ...
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Why does removing a RID by creating a clustered index lose parallelism and slow down execution by 2X

If I remove a RID lookup by replacing 2 non-clustered indices (non unique) with 2 identical clustered indicies (non-unique) where there weren't any before, why does this query slow down by a factor ...
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Sql Server, a single threaded query spawns multiple threads (or internal parellelizaion during execution)

In Sql Server, when I run a procedure or a query that takes multiple minutes, sometimes spawns multiple threads. Even though there is no MAXDOP hint or necessity in the query, I see multiple instances ...
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MySQL Cluster lock wait timeout exceeded when trying to deal with huge amount of queries

I'm trying to deal with many connections and sometime I get following error: ERROR : Lock wait timeout exceeded; try restarting transaction The bigger number of queries the least number of ...
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Why are there more MySQL deadlocks on my 8-core machine than 16-core?

I'm running a bunch of scripts in parallel that do: START TRANSACTION REPLACE INTO... REPLACE INTO... REPLACE INTO... ... COMMIT On my 8-core machine, where 8 of these processes are running in ...