I was not complaining; I think JSONB is awesome. But I am one of those people who would like to put 100's of GB (or more) JSON files into Postgres and I am concerned about file size and possible future changes to the format.
On Fri, Aug 8, 2014 at 7:10 PM, Peter Geoghegan <p...@heroku.com> wrote: > On Fri, Aug 8, 2014 at 12:06 PM, Josh Berkus <j...@agliodbs.com> wrote: > > One we ship 9.4, many users are going to load 100's of GB into JSONB > > fields. Even if we fix the compressability issue in 9.5, those users > > won't be able to fix the compression without rewriting all their data, > > which could be prohibitive. And we'll be in a position where we have > > to support the 9.4 JSONB format/compression technique for years so that > > users aren't blocked from upgrading. > > FWIW, if we take the delicious JSON data as representative, a table > storing that data as jsonb is 1374 MB in size. Whereas an equivalent > table with the data typed using the original json datatype (but with > white space differences more or less ignored, because it was created > using a jsonb -> json cast), the same data is 1352 MB. > > Larry's complaint is valid; this is a real problem, and I'd like to > fix it before 9.4 is out. However, let us not lose sight of the fact > that JSON data is usually a poor target for TOAST compression. With > idiomatic usage, redundancy is very much more likely to appear across > rows, and not within individual Datums. Frankly, we aren't doing a > very good job there, and doing better requires an alternative > strategy. > > -- > Peter Geoghegan >
