Cannot Get Dynamic Exec of SP to Return INOUT Param - postgresql

Question

Using PostgreSQL 13.2, wherein a stored procedure (the Requestor) is given a name of a list of stored procedures to run (the job group). All sp's executed this way are coded to write a log record as their last task. I have chosen to pull that 'append log' code from all of the sp's, and instead send back the log record (always a single record) using an INOUT rowtype param, but have run into trouble. In my example below, the requestor sp will load the records returned from the sp's it calls into a temp table shaped like the permanent log table.
That permanent table looks like this:
create table public.job_log (
log_id integer,
event_id integer,
job_id integer,
rows_affected integer);
Any one of the jobs that is executed by the requestor sp might look like this one:
CREATE OR REPLACE procedure public.get_log_rcd(
inout p_log_rcd public.job_log)
LANGUAGE 'plpgsql'
as
$BODY$
declare
v_log_id integer = 40;
v_event_id integer = 698;
v_job_id integer = 45;
v_rows_affected integer = 60;
begin
select
v_log_id
, v_event_id
, v_job_id
, v_rows_affected
into
p_log_rcd.log_id,
p_log_rcd.event_id,
p_log_rcd.job_id,
p_log_rcd.rows_affected;
end;
$BODY$
This sample sp doesn't do anything--it's purpose here is only to simulate initialize of the log parameters to return to caller.
Again, the requestor sp that's going to run jobs like the one above creates a temp table with the same structure as the permanent log:
drop table if exists tmp_log_cache;
create temp table tmp_log_cache as table public.job_log with no data;
If the requestor sp didn't have to do dynamic SQL, it would look something like this block here:
do
$$
declare
big_local public.job_log;
begin
call public.get_log_rcd( big_local );
insert into tmp_log_cache (
log_id
, event_id
, job_id
, rows_affected )
values (
big_local.log_id
, big_local.event_id
, big_local.job_id
, big_local.rows_affected);
end;
$$;
Doing a
select * from tmp_log_cache;
Returns a row containing the 4 column values expected, all is well. But, dynamic execution is required. And, as I'm sure most folks here know, the following dog don't hunt:
do
$$
declare
big_local public.job_log;
v_query_text varchar;
v_job_name varchar = 'public.get_log_rcd';
begin
select 'call ' || v_job_name || '( $1 );'
into v_query_text;
execute v_query_text using big_local::public.job_log;
insert into tmp_log_cache (
log_id
, event_id
, job_id
, rows_affected )
values (
big_local.log_id
, big_local.event_id
, big_local.job_id
, big_local.rows_affected);
end;
$$;
The above dynamic statement executes without error, but the insert statement only has NULL values to work with--a row is inserted, all nulls. Any suggestions warmly welcomed. The sp's that comprise the various job groups could probably have been implemented as functions, although in all cases their primary tasks are to massage, normalize, cleanse telemetry data, not to spit anything out, per se.

Answer 1

Hmm, the documentation states that "parameter symbols (...) only work in SELECT, INSERT, UPDATE, and DELETE commands.", so this probably isn't possible using parameters.
But as a workaround you can build a dynamic DO and include a variable to get the values and the INSERT in there.
DO
$o$
DECLARE
v_query_text varchar;
v_job_name varchar := format('%I.%I',
'public',
'get_log_rcd');
BEGIN
v_query_text := concat('DO ',
'$i$ ',
'DECLARE ',
' big_local public.job_log; ',
'BEGIN ',
' CALL ', v_job_name, '(big_local); ',
' INSERT INTO tmp_log_cache ',
' (log_id, ',
' event_id, ',
' job_id, ',
' rows_affected) ',
' VALUES (big_local.log_id, ',
' big_local.event_id, ',
' big_local.job_id, '
' big_local.rows_affected); ',
'END; ',
'$i$; ');
EXECUTE v_query_text;
END;
$o$;
db<>fiddle

Answer 2

Thanks--I would not have considered the ability to execute a 'do' using execute. It just would not have occurred to me. Well, here's my solution: flip to functions.
With the understanding that my 'Requestor' is only given sp's to run because that's what we had to do with SQL Server and it was reflex, I did the 1-line change needed to flip my example sp above to a function:
CREATE OR REPLACE function public.get_log_rcdf(
inout p_log_rcd public.job_log)
returns public.job_log
LANGUAGE 'plpgsql'
as
$BODY$
declare
v_log_id integer = 40;
v_event_id integer = 698;
v_job_id integer = 45;
v_rows_affected integer = 60;
begin
select
v_log_id
, v_event_id
, v_job_id
, v_rows_affected
into
p_log_rcd.log_id,
p_log_rcd.event_id,
p_log_rcd.job_id,
p_log_rcd.rows_affected;
end;
$BODY$
In fact, the change to a function required the addition of a RETURNS line. Done. Then, the dynamic call was tweaked to a SELECT and the execute modified with an INTO:
do
$$
declare
big_local public.job_log;
v_query_text varchar;
v_job_name varchar = 'public.get_log_rcdf';
begin
select 'select * from ' || v_job_name || '( $1 );'
into v_query_text;
raise info 'SQL text is: %', v_query_text;
execute v_query_text into big_local using big_local;
insert into tmp_log_cache (
log_id
, event_id
, job_id
, rows_affected )
values (
big_local.log_id
, big_local.event_id
, big_local.job_id
, big_local.rows_affected);
end;
$$;
and the process now works exactly as desired. I tidy up my handling of the dynamic function name as illustrated in the first answer, and I think we're done here.