> In the particular case of my example, Table1 has an index onCODIGO. But this is only an example. In my application there are a
lot of queries like this and in almost every cases the WHERE clause
can use an index.
>of doing the query of my example. It´s the time of completing a
> The time of 2 seconds I mentioned in my message is not the time
process which involves many queries like this.
OK, you were not very clear on this point before. The way you
explained it made it look like a simple single "select" statement of
one field was taking 2 seconds, but now if I understand you
correctly, the two seconds is how long it takes to run this query
>you are forcing Firebird to do a natural read which is the brunt of
> Adam: I don´t understand what you are saying with "I suspect
>Remembering that we were all picturing a single query taking 2
seconds, the only explanation that made sense was if the field was
not indexed. I mentioned this because I also suggested another
problem in your Delphi code which forced the optimiser to check your
query each time, even though you were effectively just changing a
parameter, however this would only account for a wasted 10-100ms per
query, certainly nothing like 2 seconds.
Now we have a better understanding of the problem, can you give the
How many queries are being executed in the process that takes 2
Does your logic look something like
qrytbl1.sql.text := 'select id from table1';
while not qrytbl1.eof do
qrytbl2.sql.text := select id from table2 where table1id = ' + CHR
(39) + qrytbl1ID.Value + CHR(39)
If so, this a huge overhead, and easily fixed using a join operation.