Re: [COMMITTERS] pgsql: Compress GIN posting lists, for smaller index size.

On 01/23/2014 09:18 PM, Stefan Kaltenbrunner wrote:
> On 01/22/2014 06:28 PM, Heikki Linnakangas wrote:
>> Compress GIN posting lists, for smaller index size.
>>
>> GIN posting lists are now encoded using varbyte-encoding, which allows them
>> to fit in much smaller space than the straight ItemPointer array format used
>> before. The new encoding is used for both the lists stored in-line in entry
>> tree items, and in posting tree leaf pages.
>>
>> To maintain backwards-compatibility and keep pg_upgrade working, the code
>> can still read old-style pages and tuples. Posting tree leaf pages in the
>> new format are flagged with GIN_COMPRESSED flag, to distinguish old and new
>> format pages. Likewise, entry tree tuples in the new format have a
>> GIN_ITUP_COMPRESSED flag set in a bit that was previously unused.
>>
>> This patch bumps GIN_CURRENT_VERSION from 1 to 2. New indexes created with
>> version 9.4 will therefore have version number 2 in the metapage, while old
>> pg_upgraded indexes will have version 1. The code treats them the same, but
>> it might be come handy in the future, if we want to drop support for the
>> uncompressed format.
>>
>> Alexander Korotkov and me. Reviewed by Tomas Vondra and Amit Langote.
>
> it seems that this commit made spoonbill an unhappy animal:
>
> http://www.pgbuildfarm.org/cgi-bin/show_log.pl?nm=spoonbill&dt=2014-01-23%2000%3A00%3A04

Hmm, all the Sparcs. Some kind of an alignment issue, perhaps? I will
investigate..

- Heikki

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- Heikki