PostgreSQL for Data Architects by 2015

PostgreSQL for Data Architects by 2015

Author:2015
Language: eng
Format: epub
Publisher: Packt Publishing


When we execute this after a database restart, we get the following output (only a few lines displayed):

Shared Hit Blocks: 0 + Shared Read Blocks: 94 + Total Runtime: 2.061

The next time, we get this:

Shared Hit Blocks: 94 + Shared Read Blocks: 0 + Total Runtime: 1.462

The difference is obvious: reads went down, hits went up, and runtime went down, implying that the data to be fetched was available in the buffer.

For a complete list of options available with EXPLAIN, refer to http://www.postgresql.org/docs/current/static/sql-explain.html.



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