Add CLAUDE.md for Claude Code guidance

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance for Claude Code when working with the amazon-redshift-utils repository.
+
+## Project Overview
+
+Amazon Redshift Utils is a collection of scripts and utilities for Amazon Redshift, a petabyte-scale data warehouse. The repository contains Python scripts, SQL scripts, stored procedures, and admin utilities to optimize Redshift cluster performance.
+
+## Repository Structure
+
+```
+/
+├── src/                          # Main source directory
+│   ├── AdminScripts/             # Diagnostic scripts for clusters
+│   ├── AdminViews/               # Views for cluster management and DDL generation
+│   ├── AnalyzeVacuumUtility/     # Automates VACUUM and ANALYZE operations
+│   ├── ColumnEncodingUtility/    # Applies optimal column encoding to tables
+│   ├── CloudDataWarehouseBenchmark/  # Performance benchmarking workloads
+│   ├── ManifestGenerator/        # Generates manifest files for COPY commands
+│   ├── MetadataTransfer/         # Metadata transfer utilities
+│   ├── QMRNotificationUtility/   # Query Monitoring Rule notifications via Lambda/SNS
+│   ├── RedshiftAutomation/       # Lambda-based automation module
+│   ├── RedshiftIDCMigrationUtility/  # IDC migration utility
+│   ├── SimpleReplay/             # Workload capture and replay utility
+│   ├── StoredProcedures/         # Example stored procedures
+│   ├── SystemTablePersistence/   # System table persistence utilities
+│   ├── UnloadCopyUtility/        # Data migration between clusters via S3
+│   ├── UserLastLogin/            # User login tracking
+│   ├── WorkloadManagementScheduler/  # WLM scheduling
+│   ├── bin/                      # Docker entrypoint scripts
+│   ├── config_constants.py       # Shared configuration constants
+│   ├── redshift_utils_helper.py  # Common helper functions
+│   └── requirements.txt          # Main Python dependencies
+├── Dockerfile                    # Docker build for running utilities
+└── README.md                     # Project documentation
+```
+
+## Key Dependencies
+
+The main dependencies (from `src/requirements.txt`):
+- `pg8000` - PostgreSQL/Redshift database driver
+- `boto3` - AWS SDK for Python
+- `redshift-connector` - Native Redshift connector
+- `pgpasslib` - pgpass file support
+- `shortuuid` - UUID generation
+
+## Running Utilities
+
+### From Command Line
+```bash
+cd src
+python3 ./<folder>/<utility> <args>
+```
+
+### Via Docker
+Build the image:
+```bash
+docker build -t amazon-redshift-utils .
+```
+
+Run utilities:
+```bash
+# Analyze & Vacuum
+docker run --net host --rm -it -e DB=my-database amazon-redshift-utils analyze-vacuum
+
+# Column Encoding
+docker run --net host --rm -it -e DB=my-database amazon-redshift-utils column-encoding
+
+# Unload/Copy
+docker run --net host --rm -it -e CONFIG_FILE=s3://... amazon-redshift-utils unload-copy
+```
+
+Use `--env-file` for environment variables:
+```bash
+docker run --net host --rm -it --env-file redshift_utils.env amazon-redshift-utils analyze-vacuum
+```
+
+## Testing
+
+Tests exist primarily for the UnloadCopyUtility:
+- Unit tests: `src/UnloadCopyUtility/tests/redshift_unload_copy_unittests.py`
+- Regression tests: `src/UnloadCopyUtility/tests/redshift_unload_copy_regressiontests.py`
+- DDL helpers tests: `src/UnloadCopyUtility/tests/ddl_helpers_tests.py`
+
+Run tests with:
+```bash
+cd src/UnloadCopyUtility
+python -m pytest tests/
+```
+
+## Authentication Options
+
+1. **KMS-encrypted password**: Base64-encoded KMS-encrypted string in config
+2. **pgpass file**: Use `.pgpass` file (requires rebuilding modules with `build.sh`)
+3. **PGPASS environment variable**: Set `$PGPASS`
+
+## Key Utilities Overview
+
+### AnalyzeVacuumUtility
+Automates VACUUM and ANALYZE based on table statistics, unsorted rows, and system alerts. Configure with `--analyze-flag` and `--vacuum-flag`.
+
+### ColumnEncodingUtility
+Analyzes compression and generates scripts to apply optimal column encoding using `ANALYZE COMPRESSION`.
+
+### UnloadCopyUtility
+Migrates data between clusters using UNLOAD to S3 (KMS-encrypted) followed by COPY. Configurable via JSON config files.
+
+### SimpleReplay
+Captures and replays workloads from audit logs. Includes extract and replay phases with configurable YAML settings.
+
+### RedshiftAutomation
+Lambda-based automation for running utilities on schedule via CloudWatch Events.
+
+## Build Scripts
+
+- `src/RedshiftAutomation/build.sh` - Builds Lambda deployment package
+- `src/QMRNotificationUtility/lambda/build.sh` - Builds QMR Lambda package
+- `src/UnloadCopyUtility/encryptValue.sh` - Encrypts values with KMS
+
+## Code Style Notes
+
+- Python 3.8+ compatible
+- Uses standard Python conventions
+- SQL scripts use Redshift-specific syntax
+- Configuration typically via environment variables or JSON/YAML files