Re: jsonb format is pessimal for toast compression - Mailing list pgsql-hackers

From Josh Berkus
Subject Re: jsonb format is pessimal for toast compression
Date
Msg-id 53ED4304.1010901@agliodbs.com
Whole thread Raw
In response to Re: jsonb format is pessimal for toast compression  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: jsonb format is pessimal for toast compression
List pgsql-hackers
On 08/14/2014 04:02 PM, Tom Lane wrote:
> Josh Berkus <josh@agliodbs.com> writes:
>> So, here's a destruction test case:
>> 200,000 JSON values (plus 2 key columns)
>> Average width 4K (+/- 1K)
>> 183 keys per JSON value
> 
> Is that 183 keys exactly each time, or is 183 the average?

Each time exactly.

> It would be useful to see min/max/avg of pg_column_size() in both
> these cases.

Well, this is 9.4, so I can do better than that.  How about quartiles?
thetype |    colsize_distribution
---------+----------------------------json    | {1777,1803,1890,1940,4424}jsonb   | {5902,5926,5978,6002,6208}

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com



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