SlowQL for VS Code

Static SQL analysis with 272 built-in rules across 14 SQL dialects. Catches security vulnerabilities, performance regressions, reliability issues, compliance risks, cost inefficiencies, and code quality problems as you type. No database connection required.

Features

272 rules across six dimensions:

Dimension	What it catches
Security	SQL injection, hardcoded credentials, privilege escalation, SSRF
Performance	Full scans, missing indexes, N+1 patterns, locking issues
Reliability	Data loss risk, race conditions, missing transactions
Quality	NULL comparison errors, implicit joins, naming issues
Cost	Cloud warehouse anti-patterns, unnecessary scans
Compliance	GDPR, HIPAA, PCI-DSS, SOX violations

14 SQL dialects with dialect-specific rules:

PostgreSQL, MySQL, SQL Server (T-SQL), Oracle, SQLite, Snowflake, BigQuery, Redshift, ClickHouse, DuckDB, Presto, Trino, Spark, Databricks.

107 rules are dialect-aware and only fire on the relevant engine. 165 universal rules fire on all dialects.

Schema-aware validation. Point SlowQL at your DDL files to detect references to non-existent tables, columns, and get index suggestions.

Quick Start

Install SlowQL with LSP support:
```
 pip install "slowql[lsp]"
```
Install this extension from the VS Code Marketplace.
Open any .sql file. Diagnostics appear in the Problems panel automatically.

The status bar shows SlowQL state: running, error, or disabled.

Settings

Setting	Default	Description
slowql.enable	true	Enable or disable the language server
slowql.dialect	(empty, auto)	SQL dialect for dialect-specific rules
slowql.command	python	Python executable path
slowql.args	["-m", "slowql.lsp.server"]	Language server arguments
slowql.schemaFile	(empty)	Path to DDL file for schema validation
slowql.databaseUrl	(empty)	Database connection string for live schema
slowql.trace.server	off	Trace LSP communication for debugging

Dialect Selection

Set slowql.dialect to your database engine to enable dialect-specific rules. Leave empty for auto-detection.

    {
      "slowql.dialect": "postgresql"
    }

Schema Validation

Point to your DDL file to catch missing tables and columns:

    {
      "slowql.schemaFile": "db/schema.sql"
    }

Or connect to a live database:

    {
      "slowql.databaseUrl": "postgresql://user:pass@localhost:5432/mydb"
    }

Commands

Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P):

Command	Description
SlowQL: Restart Language Server	Restart the background analysis engine
SlowQL: Show Status	Show server state, dialect, and rule count

Requirements

Python 3.11+ and SlowQL with LSP extras:

    pip install "slowql[lsp]"

If using a virtual environment, set slowql.command to the full path:

    {
      "slowql.command": "/path/to/venv/bin/python"
    }

Troubleshooting

Server not starting. Check the SlowQL output channel (View then Output then SlowQL) for error details. Common causes:

slowql[lsp] not installed. Run pip install "slowql[lsp]"
Wrong Python path. Set slowql.command to your Python binary.
Virtual environment not activated. Use the full path to the venv Python.

No diagnostics appearing. Verify the file language is set to SQL (bottom right of VS Code). Check that slowql.enable is true.

SlowQL: Offline SQL Static Analyzer

Makroumi