At the default threshold
A hash near 128 fields, showing the cost either side of the cliff
type: hash keys: 1000000 elements: 100 value-bytes: 32
Redis Encoding Threshold Calculator
See where the encoding flips and what it costs. This is the page that explains why a dataset grew sharply with no code change.
Paste below, or drop a file anywhere on this panel
Or drop a file anywhere on this panel. Nothing is uploaded: the analysis runs in this tab.
The answer appears here
Paste on the left and press Calculate. Nothing leaves this tab.
Formatted
Results
Nothing else to flag.
No formatting problems, and nothing the rules object to. Worth remembering what that covers: this reads the file you pasted, not the account or cluster it will be applied to.
No finding matches that filter.
Wanted a different tool?
- Redis Memory Calculator if you want the memory total rather than the threshold itself, because that applies this cliff across a whole keyspace.
Examples
Real input you can load into the tool above. Each one shows a different thing going wrong, because that is what the tool is for.
Already past it
A collection that is already using the pointer-based encoding
type: hash keys: 1000000 elements: 500 value-bytes: 32
Common mistakes
These are the ones that fail silently. The config is accepted, nothing raises an error, and the consequence arrives later.
Raising the threshold without understanding the trade
A listpack is a flat array, so lookups within it are linear. Raising the limit to 5000 saves memory and makes every field access scan.
Instead:Raise it modestly, and only where the collection is read whole rather than by field.
Assuming the threshold applies to the value only
Both hash-max-listpack-entries and hash-max-listpack-value apply. One long field name or value converts the whole key.
Instead:Check both. A single outlier converts the key permanently.
Expecting the encoding to convert back
Redis never converts a collection back to the compact encoding, even after elements are removed.
Instead:The conversion is one way. Only recreating the key restores it.
Related redis tools
Redis Hash Slot Calculator Which of the 16,384 slots does this key land in? Redis Hash Tag Tester Will these keys survive a multi-key command? Redis Key Name Validator Legal is not the same as workable Redis Memory Calculator The encoding decides, not the data Redis Key Count to Memory The fixed cost per key Redis Bitmap Memory Calculator Sized by the highest bit, not the set ones
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