Alex Krohn <alex@gossamer-threads.com> writes:
>> What does EXPLAIN VERBOSE select * from foo where a like 'Test/%';
>> show?
Well, the indexqual is just what it should be for C locale:
:indxqual ((
{ EXPR :typeOid 16 :opType op :oper
{ OPER :opno 1061 :opid 1052 :opresulttype 16 } :args (
{ VAR :varno 1 :varattno 1 :vartype 1042 :vartypmod 29 :varlevelsup 0 :varnoold 1 :varoattno 1}
{ CONST :consttype 1042 :constlen -1 :constisnull false :constvalue 9 [ 9 0 0 0 84 101 115 116 47 ] :constbyval false
})}
{ EXPR :typeOid 16 :opType op :oper
{ OPER :opno 1058 :opid 1049 :opresulttype 16 } :args (
{ VAR :varno 1 :varattno 1 :vartype 1042 :vartypmod 29 :varlevelsup 0 :varnoold 1 :varoattno 1}
{ CONST :consttype 1042 :constlen -1 :constisnull false :constvalue 9 [
9 0 0 0 84 101 115 116 48 ] :constbyval false })}))
This mess translates as
a >= 'Test/'::bpchar AND a < 'Test0'::bpchar
which is what the LIKE index optimizer is supposed to generate.
I infer that one or the other of these conditions yields false on your
machine, which should not be happening if the thing is in C locale.
regards, tom lane