| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Gavin Flower <GavinFlower(at)archidevsys(dot)co(dot)nz>, Peter Geoghegan <pg(at)heroku(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Stephen Frost <sfrost(at)snowman(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com>, Kevin Grittner <kgrittn(at)ymail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, Larry White <ljw1001(at)gmail(dot)com> |
| Subject: | Re: jsonb format is pessimal for toast compression |
| Date: | 2014-08-14 23:15:16 |
| Message-ID: | 53ED4304.1010901@agliodbs.com |
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| Lists: | pgsql-hackers |
On 08/14/2014 04:02 PM, Tom Lane wrote:
> Josh Berkus <josh(at)agliodbs(dot)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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