Re: Postgresql, PSN hack and table limits

From: Mark Morgan Lloyd <markMLl(dot)pgsql-general(at)telemetry(dot)co(dot)uk>
To: pgsql-general(at)PostgreSQL(dot)org
Subject: Re: Postgresql, PSN hack and table limits
Date: 2011-05-01 20:42:38
Message-ID: ipkgk0$1fr$
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Tom Lane wrote:
> Jasen Betts <jasen(at)xnet(dot)co(dot)nz> writes:
>> On 2011-05-01, Mark Morgan Lloyd <markMLl(dot)pgsql-general(at)telemetry(dot)co(dot)uk> wrote:
>>> Somebody is making a very specific claim that Postgres can support a
>>> limited number of rows:
>>> "INPS (a data forensics team) said that there is 7 main Databases all
>>> hosted at different data centers but linked over a type of 'cloud' Each
>>> database uses PostGRESSQL which would mean the most amount of data each
>>> database could hold with no stability issues is aproximitely equal to
>>> that of 10,348,439 Rows"
>>> Does anybody have any idea where they've got hold of this figure?
>> the figure is within 1% of the maximun size for data stored in text
>> (or bytea) column.
> No it isn't; the max size per field is 1GB. Although actually
> manipulating such field values will probably not work very well unless
> you have a 64-bit machine, else you'll hit address-space issues.
> I could believe that a specific application using specific fields in
> a specific way in a 32-bit machine might start to hit "out of memory"
> errors for field widths somewhere in the tens-of-MB range. But the
> stated claim is about number of rows, not row width, and the exactness
> and breadth of the claim is, well, ridiculous on its face.
> I think INPS's level of knowledge about PG must be about as good as
> their ability to spell it :-(
> BTW, there *is* a hard limit of 32TB per table, arising from the limited
> size of BlockNumber. But it's hard to believe that INPS's claim has
> anything to do with that.

I suspect that INPS is something to do with the French police, so might
have been briefed by somebody who purports to know what he's talking
about. But I'm assuming that whoever put those ramblings on Pastebin is
unreliable, the only reason I mentioned it was that specific claims were
being made which might become widely repeated.

Mark Morgan Lloyd
markMLl .AT. .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]

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