add compression docs

v3-docs/docs/.vitepress/config.mts

@@ -431,6 +431,15 @@ export default defineConfig({
         ],
         collapsed: true,
       },
+      {
+        text: "Performance",
+        items: [
+          {
+            text: "WebSocket Compression",
+            link: "/performance/websocket-compression",
+          },
+        ],
+      },
     ],
 
     socialLinks: [

v3-docs/docs/performance/websocket-compression.md

@@ -0,0 +1,57 @@
+# Websocket Compression in Meteor
+
+Meteor's stream server uses the permessage-deflate extension for websocket compression by default. While compression can help reduce bandwidth usage, it may impact performance in reactivity-intensive applications due to the computational overhead of compressing numerous DDP messages.
+
+## Configuration
+
+### Disabling Compression
+
+You can disable websocket compression by setting the `SERVER_WEBSOCKET_COMPRESSION` environment variable to `false`:
+
+```bash
+SERVER_WEBSOCKET_COMPRESSION=false
+```
+
+### Custom Compression Settings
+
+To customize compression settings, set `SERVER_WEBSOCKET_COMPRESSION` to a JSON string with your desired configuration:
+
+```bash
+# Example with custom settings
+SERVER_WEBSOCKET_COMPRESSION='{"threshold": 2048, "level": 1}'
+```
+
+Available configuration options:
+
+- `threshold`: Minimum message size (in bytes) before compression is applied (default: 1024)
+- `level`: Compression level (0-9, where 0=none, 1=fastest, 9=best compression)
+- `memLevel`: Memory level (1-9, lower uses less memory)
+- `noContextTakeover`: When true, compressor resets for each message (default: true)
+- `maxWindowBits`: Window size for compression (9-15, lower uses less memory)
+
+## Verifying Compression Status
+
+You can check if compression is enabled through the Meteor shell:
+
+```javascript
+Meteor.server.stream_server.server.options.faye_server_options.extensions
+```
+
+Results interpretation:
+- `[]` (empty array): Compression is disabled
+- `[{}]` (array with object): Compression is enabled
+
+## Performance Considerations
+
+- For apps with high message throughput or frequent small updates, disabling compression may improve performance
+- Large message payloads may benefit from compression, especially over slower network connections
+- Consider monitoring CPU usage and response times when adjusting compression settings
+
+## Default Configuration
+
+When enabled, the default configuration uses:
+- Compression threshold: 1024 bytes
+- Compression level: Z_BEST_SPEED (fastest)
+- Memory level: Z_MIN_MEMLEVEL (minimum memory usage)
+- Context takeover: Disabled
+- Window bits: Z_MIN_WINDOWBITS (minimum window size)