File Foreign Table Doesn't Exist when in Exception

[Virendra Kumar <viru_7683@xxxxxxxxx>]

Hello Everyone,

I have a weird situation with file_fdw extension when I am creating a foreign table in anonymous block. Here is setup:

Create extension and server:

======================

postgres=# create extension file_fdw;
CREATE EXTENSION
postgres=# CREATE SERVER log_server FOREIGN DATA WRAPPER file_fdw;
CREATE SERVER

Here is anonymous block, when I query the foreign table (FT) created in block with incorrect data. I get error and the FT is lost. See below:

====================

postgres=# DO $$
postgres$# DECLARE
postgres$# v_ft_file_name text;
postgres$# temp_variable text;
postgres$# v_sql text;
postgres$# log_min_time date;
postgres$# BEGIN
postgres$#
postgres$# v_ft_file_name:='abc.csv';
postgres$#
postgres$# v_sql:= 'CREATE FOREIGN TABLE "'||v_ft_file_name||'"(
postgres$#                   user_name                     text,
postgres$#                   database_name                 text,
postgres$#                   connection_from               text
postgres$#                 ) SERVER log_server
postgres$#                 OPTIONS (filename ''/opt/postgres/122/data/'||v_ft_file_name||''')';
postgres$# execute v_sql;
postgres$# v_sql:='select min(user_name) from "'||v_ft_file_name||'"';
postgres$# execute v_sql into log_min_time; <-- Querying from FT with incorrect data
postgres$#    
postgres$# END;
postgres$# $$ LANGUAGE 'plpgsql';
ERROR:  missing data for column "database_name"
CONTEXT:  COPY abc.csv, line 1: "aa,bb,cc"
SQL statement "select min(user_name) from "abc.csv""
PL/pgSQL function inline_code_block line 19 at EXECUTE

postgres=#

postgres=# select ftrelid::regclass::text from pg_foreign_table
postgres-# where ftrelid::regclass::text like '%abc.csv%';
 ftrelid
---------
(0 rows)

When I don't query the FT I can see the foreign table:

=================

postgres=# DO $$

postgres$# DECLARE
postgres$# v_ft_file_name text;
postgres$# temp_variable text;
postgres$# v_sql text;
postgres$# log_min_time date;
postgres$# BEGIN
postgres$#
postgres$# v_ft_file_name:='abc.csv';
postgres$#
postgres$# v_sql:= 'CREATE FOREIGN TABLE "'||v_ft_file_name||'"(
postgres$#                   user_name                     text,
postgres$#                   database_name                 text,
postgres$#                   connection_from               text
postgres$#                 ) SERVER log_server
postgres$#                 OPTIONS (filename ''/opt/postgres/122/data/'||v_ft_file_name||''')';
postgres$# execute v_sql;
postgres$#
postgres$# v_sql:='select min(user_name) from "'||v_ft_file_name||'"';
postgres$# --execute v_sql into log_min_time; <-Commented SELECT on FT
postgres$#    
postgres$# END;
postgres$# $$ LANGUAGE 'plpgsql';
DO
postgres=#
postgres=#
postgres=# select ftrelid::regclass::text from pg_foreign_table
postgres-# where ftrelid::regclass::text like '%abc.csv%';
  ftrelid  
-----------
 "abc.csv"
(1 row)

postgres=#

When I query the table outside anonymous block it is still there. So I am thinking may be I am missing some concept here or hitting a bug:

====================

postgres=# select min(user_name) from "abc.csv";
ERROR:  missing data for column "database_name"
CONTEXT:  COPY abc.csv, line 1: "aa,bb,cc"
postgres=#
postgres=#
postgres=# select ftrelid::regclass::text from pg_foreign_table                                                                                                                                             where ftrelid::regclass::text like '%abc.csv%';
  ftrelid  
-----------
 "abc.csv"
(1 row)

Regards,

Virendra Kumar