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Using Parallel Query with Amazon Aurora for MySQL

Percona

Aurora Parallel Query response time (for queries which can not use indexes) can be 5x-10x better compared to the non-parallel fully cached operations. The second and third run used the cached data. It does not use any cache (ie: innodb buffer pool) either. This query is 100% cached. Test data and versions.

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How Parallel Plans Start Up – Part 3

SQL Performance

A reminder of the plan ( click to enlarge ): This is the first point in the process so far that an in-flight execution plan is available (SQL Server 2016 SP1 onward) in sys.dm_exec_query_statistics_xml. Additional parallel workers will be started to run the additional parallel tasks contained in branches B, C, and D. Starting Sequence.

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Percentiles don’t work: Analyzing the distribution of response times for web services

Adrian Cockcroft

I presented this analysis of response time distributions talk in 2016 — at Microxchg in Berlin ( video ). > system.time(wait1 <- normalmixEM(waiting, mu=c(50,80), lambda=.5, Changes in behavior of the system from minute to minute is going to change the height of each peak, as the workload mix and cache hit rates change.

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Nested Loops Joins and Performance Spools

SQL Performance

The general idea is to cache and replay results, saving repeated executions of inner-side operators wherever possible. When a spool is able to replay cached results, this is known as a rewind. You may find it helpful to think of a spool rebind as a cache miss, and a rewind as a cache hit. Lazy Table Spool.

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Intel discloses “vector+SIMD” instructions for future processors

John McCalpin

In the latest (October 2016) revision of Intel’s Instruction Extensions Programming Reference , Intel has disclosed a fairly dramatic departure from these “traditional” approaches. Notes on notation: C[i][j] is invariant in the innermost loop, so I refer to the values in the accumulator as elements of the C array.

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Headless WordPress: The Ups And Downs Of Creating A Decoupled WordPress

Smashing Magazine

When it comes down to how WordPress is programmed, one thing is certain: it doesn’t follow the M odel- V iew- C ontroller (MVC) design pattern that many developers are familiar with. on December 6th, 2016. Improving performance with the decoupled JSON approach. Security concerns. So, What Exactly Is A Decoupled WordPress?

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MariaDB vs MySQL: Key Differences and Use Cases

Percona

GA 23 February 2016 5.7.10-3 MyISAM is modified with segmented key caches, the default temporary table storage engine is Aria (which is a crash-safe MyISAM), the FederatedX engine is a modified FEDERATED engine, and there are more: CONNECT, Mroonga, OQGRAPH, Sequence, SphinxSE, SPIDER, TokuDB and of course MyRocks.