Re: [HACKERS] Re: [INTERFACES] using indexes with the OR clause

Jose' Soares wrote:

> David Hartwig wrote:
> >
> > In the "Connect Settings" (either global or per data source) add the
> > following line:
> > SET ksqo TO 'on'
> >
> > Stands for "Key Set Query Oprimizer". It actually breaked those nasty
> > OR's into UNIONS. There will eventually be a radio button for this.
> > We have be in a crunch lately at work.
> >
> Yes, this works well now.
>
> > Are you using row versioning? If so, you may have to overload an
> > operator for > on xid.
>
> Do you mean < I think, because my log says ERROR: Unable to find an
> ordering operator '<' for type xid
> Any way. I tried to create the operators =, < and > but I have some
> troubles to do this.
>
> I modified xidint4.c and xidint4.sql, the sources that you sent me some
> time ago, as follow:
>
> ---------------xidint4.c-------------
> /* Insight Distribution Systems - System V - Apr 1998i
> static char accntnum_c[] = "@(#)accntnum.c 1.1
> /sccs/sql/extend/s.accntnum.
> */
> #include <stdio.h> /* for sprintf() */
> #include <string.h>
> #include "postgres.h"
> #include "utils/palloc.h"
>
> bool xidint4_eq(int32 arg1, int32 arg2);
> bool xidint4_gt(int32 arg1, int32 arg2);
> bool xidint4_lt(int32 arg1, int32 arg2);
>
> bool xidint4_eq(int32 arg1, int32 arg2)
> {
> return (arg1 == arg2);
> }
>
> bool xidint4_gt(int32 arg1, int32 arg2)
> {
> return (arg1 > arg2);
> }
>
> bool xidint4_lt(int32 arg1, int32 arg2)
> {
> return (arg1 < arg2);
> }
>
> --------------------xidint4.sql---------------------------
> create function xidint4_eq(xid,int4)
> returns bool
> as '/usr/local/pgsql/lib/contrib/xidint4.so'
> language 'c';
>
> create function xidint4_gt(xid,int4)
> returns bool
> as '/usr/local/pgsql/lib/contrib/xidint4.so'
> language 'c';
>
> create function xidint4_lt(xid,int4)
> returns bool
> as '/usr/local/pgsql/lib/contrib/xidint4.so'
> language 'c';
>
> create operator = (
> leftarg=xid,
> rightarg=int4,
> procedure=xidint4_eq,
> commutator='=',
> negator='<>',
> restrict=eqsel,
> join=eqjoinsel
> );
>
> create operator < (
> leftarg=xid,
> rightarg=int4,
> procedure=xidint4_lt,
> commutator='<',
> negator='>',
> restrict=intltsel,
> join=intltjoinsel
> );
>
> create operator > (
> leftarg=xid,
> rightarg=int4,
> procedure=xidint4_gt,
> commutator='>',
> negator='<',
> restrict=intgtsel,
> join=intgtjoinsel
> );
>
> This script gives me this message for every operator it creates,
> NOTICE: buffer leak [392] detected in BufferPoolCheckLeak()
> CREATE
>
> but at end seems that it works, I can query a table as:
>
> select xmin from attivita where xmin = 92017;
> select xmin from attivita where xmin > 92016;
> select xmin from attivita where xmin < 92018;
>
> But psqlodbc.log has still the message:
>
> ERROR: Unable to find an ordering operator '<' for type xid
>
> Thanks David for your help.
>
> Jose'

Hmmm... Sound a bit strange. Lets keep an eye on it. Anyway, I have a
minimalist patch which is confined to SQL which accomplishes the same thing.
I just overload the int4 functions. Works well. If you use this patch, be
sure to DROP the other XID operators and functions that you just created to
remove any ambiguity.

++++++++++++++++++++++++++++++++++++++

create function int4eq(xid,int4)
returns bool
as ''
language 'internal';

create operator = (
leftarg=xid,
rightarg=int4,
procedure=int4eq,
commutator='=',
negator='<>',
restrict=eqsel,
join=eqjoinsel
);

create function int4lt(xid,xid)
returns bool
as ''
language 'internal';

create function int4lt(xid,xid)
returns bool
as ''
language 'internal';

create operator < (
leftarg=xid,
rightarg=xid,
procedure=int4lt,
commutator='=',
negator='<>',
restrict=eqsel,
join=eqjoinsel
);