Re: indexable and locale - Mailing list pgsql-hackers

Sorry, found messages of people objecting to the patch.  Patch reversed
out.


[Charset iso-8859-1 unsupported, filtering to ASCII...]
> Hello again,
> I thought I should start making some small contibutions before 7.0.
> 
> Attached is a patch to the old problem discussed feverly before 6.5.
> What is does:
> for locale-enabled servers: 
>     use index if last char before '%' is ascii.
> for non-locale servers: 
>     do not use locale if last char is non-ascii since it is wrong anyway.
> 
> Comments?         
> 
> regards,
> -- 
> -----------------
> G_ran Thyni
> On quiet nights you can hear Windows NT reboot!

> diff -c pgsql/src/backend/optimizer/path/indxpath.c work/pgsql/src/backend/optimizer/path/indxpath.c
> *** pgsql/src/backend/optimizer/path/indxpath.c    Wed Oct  6 18:33:57 1999
> --- work/pgsql/src/backend/optimizer/path/indxpath.c    Fri Oct 15 19:54:34 1999
> ***************
> *** 1934,1968 ****
>       op = makeOper(optup->t_data->t_oid, InvalidOid, BOOLOID, 0, NULL);
>       expr = make_opclause(op, leftop, (Var *) con);
>       result = lcons(expr, NIL);
> - 
>       /*
> !      * In ASCII locale we say "x <= prefix\377".  This does not
> !      * work for non-ASCII collation orders, and it's not really
> !      * right even for ASCII.  FIX ME!
> !      * Note we assume the passed prefix string is workspace with
> !      * an extra byte, as created by the xxx_fixed_prefix routines above.
>        */
> ! #ifndef USE_LOCALE
> !     prefixlen = strlen(prefix);
> !     prefix[prefixlen] = '\377';
> !     prefix[prefixlen+1] = '\0';
> ! 
> !     optup = SearchSysCacheTuple(OPRNAME,
> !                                 PointerGetDatum("<="),
> !                                 ObjectIdGetDatum(datatype),
> !                                 ObjectIdGetDatum(datatype),
> !                                 CharGetDatum('b'));
> !     if (!HeapTupleIsValid(optup))
> !         elog(ERROR, "prefix_quals: no <= operator for type %u", datatype);
> !     conval = (datatype == NAMEOID) ?
> !         (void*) namein(prefix) : (void*) textin(prefix);
> !     con = makeConst(datatype, ((datatype == NAMEOID) ? NAMEDATALEN : -1),
> !                     PointerGetDatum(conval),
> !                     false, false, false, false);
> !     op = makeOper(optup->t_data->t_oid, InvalidOid, BOOLOID, 0, NULL);
> !     expr = make_opclause(op, leftop, (Var *) con);
> !     result = lappend(result, expr);
> ! #endif
> ! 
>       return result;
>   }
> --- 1934,1970 ----
>       op = makeOper(optup->t_data->t_oid, InvalidOid, BOOLOID, 0, NULL);
>       expr = make_opclause(op, leftop, (Var *) con);
>       result = lcons(expr, NIL);
>       /*
> !      * If last is in ascii range make it indexable,
> !      * else let it be.
> !      * FIXME: find way to use locate for this to support
> !      *        indexing of non-ascii characters.
>        */
> !     prefixlen = strlen(prefix) - 1;
> !     elog(DEBUG, "XXX1 %s", prefix);
> !     if ((unsigned) prefix[prefixlen] < 126)
> !       {
> !         prefix[prefixlen]++;
> !         elog(DEBUG, "XXX2 %s", prefix);
> !         optup = SearchSysCacheTuple(OPRNAME,
> !                     PointerGetDatum("<="),
> !                     ObjectIdGetDatum(datatype),
> !                     ObjectIdGetDatum(datatype),
> !                     CharGetDatum('b'));
> !         if (!HeapTupleIsValid(optup))
> !           elog(ERROR, "prefix_quals: no <= operator for type %u", datatype);
> !         conval = (datatype == NAMEOID) ?
> !           (void*) namein(prefix) : (void*) textin(prefix);
> !         con = makeConst(datatype, ((datatype == NAMEOID) ? NAMEDATALEN : -1),
> !                 PointerGetDatum(conval),
> !                 false, false, false, false);
> !         op = makeOper(optup->t_data->t_oid, InvalidOid, BOOLOID, 0, NULL);
> !         expr = make_opclause(op, leftop, (Var *) con);
> !         result = lappend(result, expr);
> !       }
>       return result;
>   }

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