v1.4.9.4

## Important Notes: Eliminate Bottlenecks in Processing Large-scale Datasets

In production deployments, entity and relation metadata can grow unbounded as documents are continuously ingested. The source_id (chunk IDs) and file_path fields in entities and relations can accumulate thousands of entries, leading to:

* Performance degradation in vector database operations
* Increased storage costs
* Memory pressure during query operations
* Slower merge operations when processing new documents

LightRAG implements a configurable metadata size control system with two key features:

* Source ID limiting: Controls the maximum number of chunk IDs stored per entity/relation
* File path limiting: Controls the maximum number of file paths displayed in metadata (display-only, doesn't affect query performance)

Both features support two strategies:

* FIFO (First In First Out): Removes oldest entries when limit is reached. Best for evolving knowledge bases, keeps most recent information.
* KEEP: Keeps oldest entries, skips new ones when limit is reached. Best for stable knowledge bases, faster (fewer merge operations)

New environment variables with default values:

```
# Source ID limits (affects query performance)
MAX_SOURCE_IDS_PER_ENTITY=300
MAX_SOURCE_IDS_PER_RELATION=300
SOURCE_IDS_LIMIT_METHOD=FIFO

# File path limits (display only)
MAX_FILE_PATHS=100
```

### Auto Data Migration

**Upgrading to this version requires data migration. If your current system contains a large number of entity relationships, the upgrade process may take an extended period of time.**

## What's New
* Feat: Add offline Docker build support with embedded models and cache by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2222
* Refact: Limit Vector Database Metadata Size to **Support Large Scale Dataset** by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2240
* Feat: Add Optional LLM Cache Deletion for Document Deletion by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2244
* Refact: Add Entity Identifier Length Truncation to Prevent Storage Failures by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2245
* Refact: Add Multimodal Processing Status Support to DocProcessingStatus for **RayAnything Compatibility** by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2248

## What's Changed
* Refact: Improve query result with semantic null returns by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2218
* remove deprecated dotenv package. by @wkpark in https://github.com/HKUDS/LightRAG/pull/2229
* Refact: Frontend UI Fixes and Performance Improvements by @danielaskdd in https://github.com/HKUDS/LightRAG/pull/2234
* Security: Fix SQL injection vulnerabilities in PostgreSQL storage by @lucky-verma in https://github.com/HKUDS/LightRAG/pull/2235
* Update openai requirement from <2.0.0,>=1.0.0 to >=1.0.0,<3.0.0 by @dependabot[bot] in https://github.com/HKUDS/LightRAG/pull/2238
* Update pandas requirement from <2.3.0,>=2.0.0 to >=2.0.0,<2.4.0 by @dependabot[bot] in https://github.com/HKUDS/LightRAG/pull/2239
* Optimize PostgreSQL initialization performance by @yrangana in https://github.com/HKUDS/LightRAG/pull/2237
* fix(docs): correct typo "acivate" → "activate" by @xiaojunxiang2023 in https://github.com/HKUDS/LightRAG/pull/2243

## New Contributors
* @wkpark made their first contribution in https://github.com/HKUDS/LightRAG/pull/2229
* @lucky-verma made their first contribution in https://github.com/HKUDS/LightRAG/pull/2235
* @dependabot[bot] made their first contribution in https://github.com/HKUDS/LightRAG/pull/2238
* @xiaojunxiang2023 made their first contribution in https://github.com/HKUDS/LightRAG/pull/2243

**Full Changelog**: https://github.com/HKUDS/LightRAG/compare/v1.4.9.3...v1.4.9.4