[postgis-users] Any native compression strategies suited for a revisioning system?

[nicklas.aven]

Hi
You could take a look at the twkb format. There is encoder (ST_AsTWKB) and decoder (ST_GeomFromTWKB) in PostGIS since version 2.2. Twkb can be stored as bytea in the database. 
HTHNicklas Avén


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-------- Original message --------
From: Peter Devoy <peter at 3xe.co.uk> 
Date: 13/12/2015  15:47  (GMT+01:00) 
To: postgis-users at lists.osgeo.org 
Subject: [postgis-users] Any native compression strategies suited for a	revisioning system? 

I have been tasked with creating a revisioning system for geometries
stored by PostGIS.  To avoid data duplication I thought about storing
only diffs but because that introduces other complications I am
thinking about just storing each revision in its entirety and having a
compression mechanism minimize size on disk.

However, it seems to me that, quite rightly, Postgres's compression
algorithm (PGLZ?) is not optimised for delta encoding or high
compression ratios.  So are there any options short of me implementing
user-defined functions to wrap a compression library?

For clarity, with this method I am thinking each geometry would have a
corresponding row in which a field would hold all revisions in a JSON
data structure.


Peter
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