Re: [Monotone-devel] nvm.sqlite3.binary adapted to rosters (and finished)

[Conrad Steenberg]

Hi Christof

Just out of curiosity, do you notice speed improvements as well as the
obvious size reduction?

Thanks!

Conrad

On Fri, 2006-01-13 at 19:37 +0100, Christof Petig wrote:
> Hi,
> 
> I finished the first part (base64->BLOB) of migrating the database
> layout to use BLOBs and am very pleased with the results:
> 
> ## ------------- ##
> ## Test results. ##
> ## ------------- ##
> 
> All 298 tests behaved as expected.
> PASS: ./testsuite
> ==================
> All 2 tests passed
> ==================
> 
> $ cat MT/revision
> c60d6232e87c2f388eca77b32f77e328c967c139
> 
> ...  61265920 monotone_BLOB.db
> ...  87126016 monotone026.db
> ... 167739392 monotone025.db
> 
> So rosters shrunk the database by 50% and BLOBs shrink by another 30% !
> 
> IMHO BLOBs are as readable as base64 encoded text (containing several
> newlines) and gzip compressed values end at the first NUL byte (so they
> don't display).
> 
> I checked the diff to mainline again and did not find any strange
> arrangements (unlike the time I announced cvssync to be ready for
> review), so perhaps we might consider switching to BLOBs and rosters at
> once in 0.26final.
> 
> I wrote this patch to be minimally invasive so removing base64 coding
> from internal data structures (e.g. cert) could be a nice project for
> the future.
> 
> _Perhaps_ using BLOBs for IDs (hex->BLOB) might give a win, too. But
> that's a different story because this clearly hurts command line
> interaction with the database.
> 
>    Christof
> 
> Caveats:
> 
> sqlite> select cast('ABC' as BLOB)='ABC';
> 0
> 
> so we have to remember which columns are stored as BLOB and pass
> appropriate data types to the query (that's what queryarg is for). And
> we also have to cast revision_certs.value to TEXT before comparing it to
> a string.
> Proper use of column affinities (actually specifying a column type)
> should help a bit.
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-- 
Conrad Steenberg <address@hidden>
California Institute of Technology

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