Query permissions for a specific table in redshift (Groups and Users) - amazon-redshift

Question

I am trying to find a query that lets me get the current permissions on a specific table in Redshift, for both groups and users. I know how to do the actual grant, but I am having a heck of a time finding the correct table(s) to query to get existing permissions.
Other information:
This will be used during a programmatic operation where the table is cascade dropped and re-created to ensure we re-apply the same permissions from before the drop. If there is an option to do this in Python without a conn.execute() query I am open to that as well.
Edit:
I did find the below query before and I tried a quick short version to see if I could get groups:
SELECT *
FROM
(
SELECT
schemaname
,objectname
,usename
,groname
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'select') AND HAS_TABLE_PRIVILEGE(grp.groname, fullobj, 'select') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS sel
FROM
(
SELECT schemaname, 't' AS obj_type, tablename AS objectname, schemaname + '.' + tablename AS fullobj FROM pg_tables
UNION
SELECT schemaname, 'v' AS obj_type, viewname AS objectname, schemaname + '.' + viewname AS fullobj FROM pg_views
) AS objs
,(SELECT * FROM pg_user) AS usrs
,(SELECT * FROM pg_group) AS grp
ORDER BY fullobj
)
WHERE sel = true
and objectname = 'table_name'
This gives me an error saying it can't find the username which is a group name.

Answer 1

You can use the following query with objectname filter to find out permissions for a specific table
SELECT *
FROM
(
SELECT
schemaname
,objectname
,usename
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'select') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS sel
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'insert') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS ins
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'update') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS upd
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'delete') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS del
,HAS_TABLE_PRIVILEGE(usrs.usename, fullobj, 'references') AND has_schema_privilege(usrs.usename, schemaname, 'usage') AS ref
FROM
(
SELECT schemaname, 't' AS obj_type, tablename AS objectname, schemaname + '.' + tablename AS fullobj FROM pg_tables
UNION
SELECT schemaname, 'v' AS obj_type, viewname AS objectname, schemaname + '.' + viewname AS fullobj FROM pg_views
) AS objs
,(SELECT * FROM pg_user) AS usrs
ORDER BY fullobj
)
WHERE (sel = true or ins = true or upd = true or del = true or ref = true)
and objectname = 'my_table'

Answer 2

I finally found something I was able to pick apart for groups and hash together something:
SELECT
namespace, item, type, groname
FROM
(
SELECT
use.usename AS subject,
nsp.nspname AS NAMESPACE,
cls.relname AS item,
cls.relkind AS TYPE,
use2.usename AS OWNER,
cls.relacl
FROM
pg_user use
CROSS JOIN pg_class cls
LEFT JOIN pg_namespace nsp ON cls.relnamespace = nsp.oid
LEFT JOIN pg_user use2 ON cls.relowner = use2.usesysid
WHERE
cls.relowner = use.usesysid
AND nsp.nspname NOT IN ( 'pg_catalog', 'pg_toast', 'information_schema' )
AND nsp.nspname IN ( 'schema' )
AND relacl IS NOT NULL
ORDER BY
subject,
NAMESPACE,
item
)
JOIN pg_group pu ON array_to_string( relacl, '|' ) LIKE'%' || pu.groname || '%'
take apart from How to query user group privileges in postgresql?