Re: [HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled

2017-10-27 Thread Amit Kapila
On Fri, Oct 27, 2017 at 5:36 PM, Alvaro Herrera wrote: > Amit Kapila wrote: > >> You might want to give a try with the hash index if you are planning >> to use PG10 and your queries involve equality operations. > > So, btree indexes on monotonically increasing sequences

Re: [HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled

2017-10-27 Thread Alvaro Herrera
Amit Kapila wrote: > You might want to give a try with the hash index if you are planning > to use PG10 and your queries involve equality operations. So, btree indexes on monotonically increasing sequences don't write tons of full page writes because typically the same page is touched many times

Re: [HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled

2017-10-27 Thread Amit Kapila
On Fri, Oct 27, 2017 at 11:26 AM, sanyam jain wrote: > Hi, > > I was reading the blog > https://blog.2ndquadrant.com/on-the-impact-of-full-page-writes . > > My queries: > > How randomness of UUID will likely to create new leaf page in btree index? > In my understanding as

Re: [HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled

2017-10-27 Thread Tomas Vondra
On 10/27/2017 07:56 AM, sanyam jain wrote: > Hi, > > I was reading the > blog https://blog.2ndquadrant.com/on-the-impact-of-full-page-writes . > For the record, I assume you're referring to this part: With BIGSERIAL new values are sequential, and so get inserted to the same leaf

[HACKERS] Burst in WAL size when UUID is used as PK while full_page_writes are enabled

2017-10-26 Thread sanyam jain
Hi, I was reading the blog https://blog.2ndquadrant.com/on-the-impact-of-full-page-writes . My queries: How randomness of UUID will likely to create new leaf page in btree index? In my understanding as the size of UUID is 128 bits i.e. twice of BIGSERIAL , more number of pages will be