Compression

Dictionary Encoding

Dictionary encoding means: instead of storing the same string over and over, store each unique string once in a dictionary and replace every occurrence with a tiny integer ID. In trace storage, strings like service.name=api-gateway appear in thousands of spans — without dictionary encoding, each copy wastes memory.

① Raw Span Data

Below are 20 example spans with three string fields each. Notice how many strings repeat.

#	service.name	http.method	span.name

② Encode

Click to replace every string with its dictionary ID. Watch the data shrink.

Dictionary (ID → String)

ID	String	Bytes

Encoded Data

#	service	method	name

③ Compression Stats

④ Add Custom Spans

Add your own spans and see how the dictionary grows — or doesn't — when strings repeat.

Try adding a span with an existing service name — the dictionary won't grow, but a new ID reference will appear.