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Displaying posts with tag: dataset (reset)
Advantages of weighted lists in RDBMS processing

A list is simply a list of things. The list has no structure, except in some cases, the length of the list may be known. The list may contain duplicate items. In the following example the number 1 is included twice.

Example list:


A set is similar to a list, but has the following differences:

  1. The size of the set is always known
  2. A set may not contain duplicates

You can convert a list to a set by creating a 'weighted list'. The weighted list includes a count column so that you can determine when an item in the list appears more than once:


Notice that there are two number 1 values in the weighted list. In order to make insertions into such a list scalable, consider using partitioning to avoid large indexes.

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MySQL: Using Views as Performance Improvement Tools

The most basic and most oft-repeated task that a DBA has to accomplish is to look at slow logs and filter out queries that are suboptimal, that consume lots of unnecessary resources and that hence slow down the database server. This post looks at why and how VIEWs can help against such suboptimal operations.

Tools to generate large synthetic data sets for testing?

I need to generate large (1TB-3TB) synthetic MySQL datasets for testing, with a number of requirements:

a) custom output formatting (SQL, CSV, fixed-len row, etc)
b) referential integrity support (ie, child tables should reference PK values, no orphans,etc)
c) able to generate multiple tables in parallel
d) preferably able to operate without a GUI and/or manual intervention
e) uses a well defined templating construct for data generation
f) preferably open source

Does anyone out there know of a product that meets at least most of these requirements?

I found a PHP based data generation script ( that is extensible in its output formatting, so it should do everything I need it to do.

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