Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-10 Thread John Turner
On Sun, Sep 10, 2017 at 1:24 PM Tom Lane wrote: > > For every other purpose, PG just pays attention to the actual column > values' lengths. > > Thanks for elaborating, Tom. This would appear to be a(nother) case where PG represents the voice of sanity as compared with 'the

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-10 Thread Tom Lane
John Turner writes: > On Sun, Sep 10, 2017 at 10:42 AM Merlin Moncure wrote: >> Nope. Memory usage is proportional to the size of the string, not the >> maximum length for varchar. Maximum length is a constraint. > Ok, thanks for verifying. I was

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-10 Thread John Turner
On Sun, Sep 10, 2017 at 10:42 AM Merlin Moncure wrote: > On Friday, September 8, 2017, John Turner wrote: > >> >> >> On Fri, Sep 8, 2017 at 6:57 AM Tom Lane wrote: >> >>> Ron Johnson writes: >>> > Based on

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-10 Thread Merlin Moncure
On Friday, September 8, 2017, John Turner wrote: > > > On Fri, Sep 8, 2017 at 6:57 AM Tom Lane > wrote: > >> Ron Johnson >

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-08 Thread John Turner
On Fri, Sep 8, 2017 at 6:57 AM Tom Lane wrote: > Ron Johnson writes: > > Based on LENGTH(offending_column), none of the values are more than 144 > > bytes in this 44.2M row table. Even though VARCHAR is, by definition, > > variable length, are there

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-08 Thread Merlin Moncure
On Thu, Sep 7, 2017 at 10:48 PM, Ron Johnson wrote: > Hi, > > v 9.2.7 > > Based on LENGTH(offending_column), none of the values are more than 144 > bytes in this 44.2M row table. Even though VARCHAR is, by definition, > variable length, are there any internal design issues

Re: [GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-08 Thread Tom Lane
Ron Johnson writes: > Based on LENGTH(offending_column), none of the values are more than 144 > bytes in this 44.2M row table. Even though VARCHAR is, by definition, > variable length, are there any internal design issues which would make > things more efficient if it

[GENERAL] B-tree index on a VARCHAR(4000) column

2017-09-07 Thread Ron Johnson
Hi, v 9.2.7 Based on LENGTH(offending_column), none of the values are more than 144 bytes in this 44.2M row table. Even though VARCHAR is, by definition, variable length, are there any internal design issues which would make things more efficient if it were dropped to, for example,