Re: Do we need multi-column frequency/histogram stats? WAS Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Tomas Vondra
On 04/23/2017 04:16 PM, Bruce Momjian wrote: On Sun, Apr 23, 2017 at 10:01:16AM -0400, Bruce Momjian wrote: On Sun, Apr 23, 2017 at 11:44:12AM +0100, Simon Riggs wrote: For us "functional dependency" would sound like something to do with functions (e.g. CREATE FUNCTION), so just "dependency" ap

Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Tomas Vondra
On 04/23/2017 12:44 PM, Simon Riggs wrote: On 23 April 2017 at 09:17, Dean Rasheed wrote: On 23 April 2017 at 03:37, Bruce Momjian wrote: In looking at the new multi-column statistics "dependency" option in Postgres 10, I am quite confused by the term "dependency". Wouldn't "correlation" be

Do we need multi-column frequency/histogram stats? WAS Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Bruce Momjian
On Sun, Apr 23, 2017 at 10:01:16AM -0400, Bruce Momjian wrote: > On Sun, Apr 23, 2017 at 11:44:12AM +0100, Simon Riggs wrote: > > For us "functional dependency" would sound like something to do with > > functions (e.g. CREATE FUNCTION), so just "dependency" appears to me > > to be the best term for

Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Bruce Momjian
On Sun, Apr 23, 2017 at 11:44:12AM +0100, Simon Riggs wrote: > For us "functional dependency" would sound like something to do with > functions (e.g. CREATE FUNCTION), so just "dependency" appears to me > to be the best term for this. > > There are multiple statistics for dependency stored, hence

Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Simon Riggs
On 23 April 2017 at 09:17, Dean Rasheed wrote: > On 23 April 2017 at 03:37, Bruce Momjian wrote: >> In looking at the new multi-column statistics "dependency" option in >> Postgres 10, I am quite confused by the term "dependency". Wouldn't >> "correlation" be clearer and less confusing as "colum

Re: [HACKERS] Statistics "dependency"

2017-04-23 Thread Dean Rasheed
On 23 April 2017 at 03:37, Bruce Momjian wrote: > In looking at the new multi-column statistics "dependency" option in > Postgres 10, I am quite confused by the term "dependency". Wouldn't > "correlation" be clearer and less confusing as "column dependency" > already means something else. > Actu

[HACKERS] Statistics "dependency"

2017-04-22 Thread Bruce Momjian
In looking at the new multi-column statistics "dependency" option in Postgres 10, I am quite confused by the term "dependency". Wouldn't "correlation" be clearer and less confusing as "column dependency" already means something else. -- Bruce Momjian http://momjian.us EnterpriseDB