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Re: [HACKERS] tables >2GB

From: dg(at)illustra(dot)com (David Gould)
To: maillist(at)candle(dot)pha(dot)pa(dot)us (Bruce Momjian)
Cc: maillist(at)candle(dot)pha(dot)pa(dot)us, hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] tables >2GB
Date: 1998-03-19 20:09:43
Message-ID: 9803192009.AA07425@hawk.illustra.com (view raw or flat)
Thread:
Lists: pgsql-hackers
> > Now that we know the storage manager code that splits tables over 2GB
> > into separate files doesn't work(Irix), can we rip out that code and
> > just use the OS code to access >2GB files as normal files.  Now, most
> > OS's can support 64-bit files and file sizes.
> > 
> > Because it is isolated in the storage manager, it should be easy.
> 
> Can someone knowledgeable make a patch for this for our mega-patch?
> 

There are still quite a few OS's out there that do not support >2GB files
yet. Even my beloved Linux (x86)...

So, how about we fix the storage manager instead?

A neat thing that Illustra does is allow you to stripe a table across
multiple directories. You get big tables, easy storage management, and
a nice performance boost.

create stripedir('stripe1', '/disk1/data/stripe1');
create stripedir('stripe2', '/disk2/data/stripe2');

create table giant_table (...) with (stripes 4, 'stripe1', 'stripe2');
 -- the '4' is the number of pages to interleave.

Then the smgr just distributes the blocks alternately across the stripes.

read_block(blockno, ...stripeinfo)
{
   ...
   stripe = (blockno / stripe_interleave ) % number_of_stripes;
   stripe_block = blockno / number_of_stripes;

   fd = stripe_info->fd[stripe];
   lseek(fd, stripe_block * BLOCKSIZE, SEEK_SET);
   ...
}

All vastly oversimplified of course....

-dg

David Gould            dg(at)illustra(dot)com           510.628.3783 or 510.305.9468 
Informix Software  (No, really)         300 Lakeside Drive  Oakland, CA 94612
 - I realize now that irony has no place in business communications.

   
   

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Next:From: The Hermit HackerDate: 1998-03-19 20:14:24
Subject: Re: [HACKERS] tables >2GB
Previous:From: Bruce MomjianDate: 1998-03-19 19:57:13
Subject: Re: AW: [HACKERS] varchar() vs char16 performance

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