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Fundamentals of table expressions, Part 7 – CTEs, optimization considerations

SQL Performance

I explained that when SQL Server optimizes a query involving derived tables, it applies transformation rules to the initial tree of logical operators produced by the parser, possibly shifting things around across what were originally table expression boundaries. Here’s the attempted solution using a CTE: WITH C AS. ( FROM Sales.

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Which is the Best MongoDB GUI? — 2019 Update

Scalegrid

In 2014, we discussed 4 of the top MongoDB GUIs: MongoVue, MongoHub, RockMongo, and Robo 3T (formerly Robomongo), and again in 2016: MongoDB Compass, Robo 3T, Studio 3T, and MongoBooster. Should have an excellent way to measure server and query performance. Import data from RDBMS like MySQL, PostgreSQL, and SQL Server.

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The challenge is on! Community call for creating the fastest number series generator

SQL Performance

L0 AS ( SELECT 1 AS c. Figure 1: Plan for base CTE cardinality of 2.

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Please help with STRING_SPLIT improvements

SQL Performance

We're mid-cycle between releases, where we're not yet hearing about any of the features planned for SQL Server vNext. In SQL Server 2016, STRING_SPLIT solved a long-missing gap in a language that, admittedly, was not intended for complicated string processing. And that is what I want to bring up today.

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bpftrace (DTrace 2.0) for Linux 2018

Brendan Gregg

C @ns: [256, 512) 10900 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | [512, 1k) 18291 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| [1k, 2k) 4998 |@@@@@@@@@@@@@@ | [2k, 4k) 57 | | [4k, 8k) 117 | | [8k, 16k) 48 | | [16k, 32k) 109 | | [32k, 64k) 3 | |. ply is also C, whereas bpftrace is C++. # Attaching 2 probes. ^C

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Use Physical Backups With MySQL InnoDB Redo Log Archiving

Percona

This issue most often occurs when there is significant MySQL server activity during the backup operation, and the redo log file storage media operates faster than the backup storage media. Enabling redo log archiving on the server requires setting a value for the innodb_redo_log_archive_dirs system variable. Press ^C to stop.

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How Parallel Plans Start Up – Part 3

SQL Performance

This is the third in a five-part series taking a deep dive into the way SQL Server row mode parallel plans start executing. 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.

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