Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-10-06 Thread Robert Haas
On Tue, Sep 16, 2014 at 6:49 AM, Heikki Linnakangas hlinnakan...@vmware.com wrote: As it happens, I also wrote an implementation of Slice-by-4 the other day If Heikki's version works I see little need to use my/Abhijit's patch. That version has part of it under the zlib license. If Heikki's

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-16 Thread Amit Kapila
On Sat, Sep 13, 2014 at 1:33 AM, Heikki Linnakangas hlinnakan...@vmware.com wrote: On 09/12/2014 10:54 PM, Abhijit Menon-Sen wrote: At 2014-09-12 22:38:01 +0300, hlinnakan...@vmware.com wrote: We probably should consider switching to a faster CRC algorithm again, regardless of what we do with

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-16 Thread Andres Freund
On 2014-09-16 15:43:06 +0530, Amit Kapila wrote: On Sat, Sep 13, 2014 at 1:33 AM, Heikki Linnakangas hlinnakan...@vmware.com wrote: On 09/12/2014 10:54 PM, Abhijit Menon-Sen wrote: At 2014-09-12 22:38:01 +0300, hlinnakan...@vmware.com wrote: We probably should consider switching to a

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-16 Thread Heikki Linnakangas
On 09/16/2014 01:28 PM, Andres Freund wrote: On 2014-09-16 15:43:06 +0530, Amit Kapila wrote: On Sat, Sep 13, 2014 at 1:33 AM, Heikki Linnakangas hlinnakan...@vmware.com wrote: On 09/12/2014 10:54 PM, Abhijit Menon-Sen wrote: At 2014-09-12 22:38:01 +0300, hlinnakan...@vmware.com wrote: We

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-16 Thread Andres Freund
On 2014-09-16 13:49:20 +0300, Heikki Linnakangas wrote: I used http://create.stephan-brumme.com/crc32/#slicing-by-8-overview as reference - you can probably see the similarity. Any implementation is going to look more or less the same, though; there aren't that many ways to write the

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-16 Thread Amit Kapila
On Tue, Sep 16, 2014 at 4:27 PM, Andres Freund and...@2ndquadrant.com wrote: On 2014-09-16 13:49:20 +0300, Heikki Linnakangas wrote: I used http://create.stephan-brumme.com/crc32/#slicing-by-8-overview as reference - you can probably see the similarity. Any implementation is going to look

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-12 Thread Andres Freund
On 2014-09-12 23:03:00 +0300, Heikki Linnakangas wrote: On 09/12/2014 10:54 PM, Abhijit Menon-Sen wrote: At 2014-09-12 22:38:01 +0300, hlinnakan...@vmware.com wrote: We probably should consider switching to a faster CRC algorithm again, regardless of what we do with compression. As it

Re: CRC algorithm (was Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes)

2014-09-12 Thread Arthur Silva
Em 12/09/2014 17:23, Andres Freund and...@2ndquadrant.com escreveu: On 2014-09-12 23:03:00 +0300, Heikki Linnakangas wrote: On 09/12/2014 10:54 PM, Abhijit Menon-Sen wrote: At 2014-09-12 22:38:01 +0300, hlinnakan...@vmware.com wrote: We probably should consider switching to a faster CRC