MEMORY PURGE error: Uncertain data type coverage

Goal

Determine whether the MEMORY PURGE command in Redis 7.0 affects all data types or only specific ones such as strings and lists.

Constraints & Uncertainty

• The command operates on the internal memory allocator (jemalloc or tcmalloc) without explicit documentation of which data structures trigger a purge.
• Community reports suggest differing results for hashes and sets, but no definitive statement exists in the official docs.
• Using the command on a busy instance can introduce latency spikes, so verification must be performed in a controlled environment.

Open Questions

1. Which Redis data types (e.g., strings, lists, hashes, sets, sorted sets) are guaranteed to be considered by MEMORY PURGE?
2. Does the effect of the purge differ between jemalloc and tcmalloc, and if so, how can that be measured?
3. Are there any hidden side‑effects on memory fragmentation metrics when purging complex data structures?