I've got help to avoid the sort with the previous query, however now
this query suddenly (well, the table size has doubled, so it isn't
that suddenly) takes over a minute to execute.

Here's the query:

select stationnodeid, max(packetid)+1 as q
from roireal_messages group by stationnodeid

Here's the plan:

PLAN (MY_MESSAGES ORDER RDB$PRIMARY3)

Here's the table metadata:

CREATE TABLE "MY_MESSAGES"
(
"NODEID" INTEGER NOT NULL,
"PID" INTEGER NOT NULL,
"MSG" VARCHAR(2000) NOT NULL,
"VALIDTO" TIMESTAMP,
PRIMARY KEY ("NODEID", "PID")
);

The table contains approximately 1 000 000 records, where 99% is for
only one nodeid. Is there any way I can speed up the query execution
radically?

I'm using Firebird 1.5.2 and Windows Server 2003.

// David