Re: Where to find information on the new HOT tables?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Dimitri Fontaine wrote:
-- Start of PGP signed section.
> Le Thursday 07 February 2008 20:43:57 Bruce Momjian, vous avez ?crit?:
> > Does the release note item on HOT need additions?
> 
> If I put the release not item on HOT here:
> 
> -=-=-=-
> Heap-Only Tuples (HOT) accelerate space reuse for most UPDATEs and DELETEs 
> (Pavan Deolasee, with ideas from many others) 
> 
> UPDATEs and DELETEs leave dead tuples behind, as do failed INSERTs. Previously 
> only VACUUM could reclaim space taken by dead tuples. With HOT dead tuple 
> space can be reclaimed     at the time of INSERT or UPDATE if no changes are made 

                         ^^^

> to indexed columns. This allows for more consistent performance. Also, HOT 
> avoids adding duplicate index entries.
> -=-=-=-

OK, what I did was to add the word "automatically" at the location
indicated.  Hopefully that will help.

> I'd say it only misses the transparent & automatic precision, telling the 
> users they don't have anything to do about HOT: PostgreSQL is able on its own 
> to decide when HOT is or is not safe to use.
> And I have to get it back that documentation is not verbose enough about how 
> HOT is working, just that you have to know where to look...
> 
> What about Alvaro's concern about manual vacuuming policies editing wrt to 
> HOT?

I think most people will be using autovacuum, and those who aren't will
have to realize that HOT makes vacuuming less needed.

-- 
  Bruce Momjian  <bruce@xxxxxxxxxx>        http://momjian.us
  EnterpriseDB                             http://postgres.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

---------------------------(end of broadcast)---------------------------
TIP 7: You can help support the PostgreSQL project by donating at

                http://www.postgresql.org/about/donate

[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux