# Tenzir Node v5.20.0

We continue our quest for better memory usage by switching out the memory allocator to the battle-tested `mimalloc`, as well as adding metrics collecting for memory usage.

## 🚀 Features

### Improved memory allocation & metrics

Dec 17, 2025 · [@IyeOnline](https://github.com/IyeOnline) · [#5512](https://github.com/tenzir/tenzir/pull/5512), [#5544](https://github.com/tenzir/tenzir/pull/5544)

We have expanded the `metrics "memory"` the application provides. When enabled, you can now see metrics for memory allocated via different means. Since this metrics collection affects every single allocation, it is currently disabled by default. To enable collection of these statistics, you can set an environment variable `TENZIR_ALLOC_STATS=true`.

Changed metric layout

This change also changes the structure of `tenzir.metrics.memory`. The system-wide stats `total_bytes`, `free_bytes` and `used_bytes` are now grouped under a `system` key to differentiate them from the `process` memory usage and per-component memory usage added in this release. These process metrics were previously only found in `metrics.process`.

We also switched the default memory allocator used on all platforms to [mimalloc](https://github.com/microsoft/mimalloc), which may reduce the effective memory usage of Tenzir.

## 🔧 Changes

### More permissive syslog parsing

Nov 3, 2025 · [@jachris](https://github.com/jachris) · [#5541](https://github.com/tenzir/tenzir/pull/5541)

The parser for RFC 5424 syslog messages now accepts structured data that slightly diverges from the RFC 5424 specification. In particular, quotes and other special characters are allowed in values unless it’s ambiguous where they belong to.

## 🐞 Bug Fixes

### Error reporting in `load_balance`

Nov 3, 2025 · [@jachris](https://github.com/jachris) · [#5542](https://github.com/tenzir/tenzir/pull/5542)

The `load_balance` operator now correctly reports errors that happen during the actual execution.

### Fixed a shutdown crash in `save_tcp`

Oct 29, 2025 · [@tobim](https://github.com/tobim) · [#5540](https://github.com/tenzir/tenzir/pull/5540)

We fixed an issue that caused the `save_tcp` operator to occasionally crash while shutting down.

[ Download on GitHub ](https://github.com/tenzir/tenzir/releases/tag/v5.20.0)

[Get the release artifacts and source code.](https://github.com/tenzir/tenzir/releases/tag/v5.20.0)