Firebird 6.0.0 complains about plan clause on restore which it uses later on

[tonne1]

FB 6.0.0.2068 issues a warning on restore of a FB5 DB if it finds a plan clause in PSQL, although the engine (FB6) uses this plan later on:

gbak: WARNING:index "PUBLIC"."IDX_CONF" cannot be used in the specified plan

test case:

-- in a FB5 DB:

CREATE TABLE CONF (
  UID   INTEGER NOT NULL,
  PARAM VARCHAR(30) NOT NULL,
  VAL  VARCHAR(100) NOT NULL
);

CREATE INDEX IDX_CONF
ON CONF (UID);

create procedure use_plan
returns (
  result integer
)
as
begin
  select uid from conf where uid = 1
  PLAN (CONF INDEX (IDX_CONF))
  into :result;
  suspend;
end;

-- Backup, then restore with FB6. The above mentioned warning comes up. Then:

-- FB6 uses the plan
select uid from conf where uid = 1
PLAN (CONF INDEX (IDX_CONF))

-- even without the plan clause
select uid from conf where uid = 1

There is no problem with the plan, it is applicable and the engine uses it. Looks more like a glitch in the processing of plan clauses in SPs.

[sim1984]

Specifying explicit plans is evil. It's better to get rid of this in stored routines.

[tonne1]

Of course, but there are very few situations where they have been the last resort, the same goes for plan hints. I'd rather avoid workarounds to help the optimizer. While testing FB6 I found that some of those legacies are not necessary any more. Not yet sure if all of them can go.

But this ticket is about processing plan clauses in FB6. If something is a legitimate part of the language, it should be processed correctly.