diskspace usage recovered on db rebuild - Mailing list pgsql-general

From David Link
Subject diskspace usage recovered on db rebuild
Date
Msg-id 424D8313.9080801@soundscan.com
Whole thread Raw
Responses Re: diskspace usage recovered on db rebuild  (Lonni J Friedman <netllama@gmail.com>)
Re: diskspace usage recovered on db rebuild  (Scott Marlowe <smarlowe@g2switchworks.com>)
List pgsql-general
Greetings worthymen.

I have a question regarding filesystem disk space usage.

We have a production database containing 5 years of sales data.
Linux 2.6.5; Postgresq 7.4.7.  VACUUM ANALZYE the entire database
everynight (about 40min).
It's size, @SUM(pg_class.relpages) * 8192K, is ...

  About 66 Gigabytes on disk.

When I rebuild the database (using pg_dump and pgsql ), the new
resultant database is ..

  About 48 Gigabytes on disk.

A 27% space savings.

Can someone tell me why that is?

Thank you,
David Link
White Plains, NY
Long live Postgres.




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