Hello,
After upgrading from PostgreSQL 12.19 to PostgreSQL 16.3 the function "array_agg" gives me the following error under
certainconditions.
ERROR: input of anonymous composite types is not implemented
I was also able reproduce the issue on PostgreSQL 17.4 via the latest currently available Docker image.
Please see the following SQL script for the minimum reproduction.
```
drop table if exists my_table;
create table my_table
(
my_text text
);
-- Insert a minimum of 200,000 rows.
do
$$
declare
counter integer := 0;
begin
while counter < 200000
loop
INSERT INTO my_table (my_text) VALUES ('A simple sentence.');
counter := counter + 1;
end loop;
end;
$$;
select array_agg(t)
from (select my_text from my_table WHERE my_text != '') t;
```
On my machine the issue appears if 200,000 or more rows exist. I used EXPLAIN and noticed that the query plan is
differentif this condition is met.
This is the query plan if fewer than 200,000 rows exist.
```
Aggregate (cost=1935.40..1935.41 rows=1 width=32)
-> Seq Scan on my_table (cost=0.00..1719.90 rows=86199 width=32)
Filter: (my_text <> ''::text)
```
This is the query plan if more than 200,000 rows exist.
```
Finalize Aggregate (cost=3801.65..3801.66 rows=1 width=32)
-> Gather (cost=3801.53..3801.64 rows=1 width=32)
Workers Planned: 1
-> Partial Aggregate (cost=2801.53..2801.54 rows=1 width=32)
-> Parallel Seq Scan on my_table (cost=0.00..2548.00 rows=101411 width=32)
Filter: (my_text <> ''::text)
```
I am also able to reproduce the issue on AWS RDS PostgreSQL 16.3.
Thank you!
