Cached list queries now use up to 69% less memory and serve up to 29% more requests_
Appwrite now serializes key-value cache entries in a binary format instead of JSON. Cached list responses consume up to 69% less memory, and cached list throughput increases by up to 29%.
The TTL cache for list queries lets Appwrite serve a repeated listRows call from the key-value cache instead of the database. On a cache hit, Appwrite reads the stored entry, deserializes it into rows, and builds the response.
Appwrite now stores that cache in a binary format instead of JSON. Each cached page is smaller, and Appwrite reads it faster. In benchmarks, cached list queries used up to 69% less memory and served up to 29% more requests per second.
The cache now uses a binary format instead of JSON
Appwrite previously serialized every cache entry as JSON. Because JSON is a text format, each row in a cached page repeats every column name, and numbers are stored as strings of digits. Every cache hit required parsing the full payload.
The cache now uses a compact binary serialization format. It stores each repeated string, such as a column name, once per entry and encodes numbers natively. Appwrite writes and reads fewer bytes per entry and spends less CPU time on deserialization.
Larger pages repeat the same column names more times, so they get the biggest saving.
Cached pages use up to 69% less memory
The table shows the size of one cached page in the key-value cache for each page size.
| Rows per page | JSON | Binary | Reduction |
|---|---|---|---|
| 25 | 16.3 KB | 10.3 KB | 37% |
| 100 | 66.6 KB | 33.6 KB | 50% |
| 250 | 167.8 KB | 64.4 KB | 62% |
| 1,000 | 672.8 KB | 218.9 KB | 67% |
| 5,000 | 3.38 MB | 1.06 MB | 69% |
The same cache memory now holds about three times as many cached pages of 1,000 rows.
The saving applies to the whole cache. After a mixed workload of 200 cached queries, 500 single-row reads, and the table schemas, the full cache used 2.65 MB instead of 5.66 MB.
Cached list queries serve up to 29% more requests
One Appwrite server handled these cached listRows requests per second, with 8 requests in flight at a time.
| Rows per page | JSON | Binary | Change |
|---|---|---|---|
| 25 | 508 | 533 | +5% |
| 50 | 445 | 485 | +9% |
| 100 | 350 | 398 | +14% |
| 250 | 215 | 267 | +24% |
| 500 | 146 | 175 | +20% |
| 1,000 | 85 | 109 | +29% |
| 2,500 | 38.7 | 47.6 | +23% |
| 5,000 | 19.0 | 24.3 | +28% |
The gain stops growing at about 1,000 rows. The binary format only speeds up the cache read. Appwrite still converts each response to JSON before it sends it to the client, and a page of 5,000 rows is 3.4 MB of JSON. That work also grows with the page size, so it limits the gain. Cache memory has no such conversion step, so the memory saving keeps growing.
Single cached requests are up to 22% faster
At a concurrency of one, latency for a cached page of 1,000 rows dropped from 42.0 ms to 32.6 ms. For a page of 5,000 rows, latency dropped from 217.8 ms to 175.0 ms.
Requests without a TTL are slightly faster
Appwrite also uses the key-value cache for data it reads on almost every request, such as sessions, API keys, and table schemas. These entries now use the binary format too. Requests that don't use a TTL, such as a single getRow call or a call for the signed-in account, were about 5% faster in the benchmark.
How the benchmark ran
- The test used self-hosted Appwrite 2.3 on a single machine, with a TablesDB table of 10,000 rows. The table had text, enum, array, integer, float, boolean, and datetime columns.
- Both runs used the same server and the same data. The only difference was the cache format.
- The runs alternated between JSON and binary 8 times, with the cache cleared before each run. The tables show the median of 4 runs for each format.
- Each page size got up to 3,000 measured requests after a warm-up, and every request succeeded.
Availability
The binary cache format ships in self-hosted Appwrite 2.3, so the memory and throughput improvements in this post apply to self-hosted instances after the upgrade. Self-hosted instances need no migration and no cache flush. After the upgrade, Appwrite reads an old JSON entry as a cache miss, loads the data from the database, and writes the entry again in the binary format. Cache misses rise for a short time after the upgrade.
