analyze_db_health incorrectly parses double quotation marks for db objects with them

[ChristophorusReyhan]

The MCP tools is checking dbarepo, but nowhere in the documentation that mention this.
Here's the response:

╭──────────────────── ✅ Tool Response postgres-mcp_8000.analyze_db_health ─────────────────────╮
│                                                                                               │
│  Arguments:                                                                                   │
│                                                                                               │
│                                                                                               │
│  {                                                                                            │
│    "health_type": "all"                                                                       │
│  }                                                                                            │
│                                                                                               │
│  Response:                                                                                    │
│                                                                                               │
│  Error calculating database health: relation "dbarepo."Count_Session_id_seq"" does not exist  │
│  LINE 5:                 FROM "dbarepo"."""Count_Session_id_seq"""                            │
│                               ^                                                               │
│                                                                                               │
╰───────────────────────────────────────────────────────────────────────────────────────────────╯

[ChristophorusReyhan]

Turns out it's a permission problem, whoops.

[ChristophorusReyhan]

Turns out, it is not permission issue. My bad

In psql i can describe it just fine using a read only user

IMBI=# \d dbarepo."Count_Session_id_seq"
               Sequence "dbarepo.Count_Session_id_seq"
  Type   | Start | Minimum |  Maximum   | Increment | Cycles? | Cache
---------+-------+---------+------------+-----------+---------+-------
 integer |     1 |       1 | 2147483647 |         1 | no      |     1
Owned by: dbarepo."Count_Session".id

I think the problem is the way double quotes is being parsed in sequence_health_calc.py.
In here:

attrs = await SafeSqlDriver.execute_param_query(
    self.sql_driver,
    """
    SELECT
        has_sequence_privilege('{}', 'SELECT') AS readable,
        last_value
    FROM {}
    """,
    [Identifier(schema, sequence), Identifier(schema, sequence)],
)

The problem is that Identifier(schema, sequence) is being passed a sequence name that likely already contains quotes from the parsing, and then Identifier() is adding more quotes.
So if sequence = '"Count_Session_id_seq"' (string with quotes), then Identifier(schema, sequence) produces "dbarepo"."""Count_Session_id_seq""".

See the error FROM "dbarepo"."""Count_Session_id_seq"""

The _parse_sequence_name method needs to strip quotes from the parsed name, maybe something like this?:

def _parse_sequence_name(self, default_value: str) -> tuple[str, str]:
    """Parse schema and sequence name from default value expression."""
    # Remove nextval and cast parts
    clean_value = default_value.replace("nextval('", "").replace("'::regclass)", "")
    clean_value = clean_value.replace("('", "").replace("'::text)", "")
    
    # Split into schema and sequence
    parts = clean_value.split(".")
    if len(parts) == 1:
        schema, seq_name = "public", parts[0]
    else:
        schema, seq_name = parts[0], parts[1]
    
    # Remove quotes from both schema and sequence name
    schema = schema.strip('"')
    seq_name = seq_name.strip('"')
    
    return schema, seq_name