README

IsapiScale

a pair of hints to make Delphi isapi web app scalable and reliable

of course Delphi has the safe memory as Rust, the OOP quicker and elegant than C++ thanks to an optimized VMT, faster execution time due to smaller pe size that fit into L1 cpu cache

so for newbies there it is a sample to make Windows Server isapi applications flying

1. using a scalable allocator (see mine repositories)
2. set keep-alive
3. set max connections higher
4. don't use globally unique firedac elements also saving time to recreate connections and queries, so:
5. manage easy threadvar for database objects
6. use database pooling
7. let me suggest a fastest json parser https://github.com/ahausladen/JsonDataObjects and use type casting instead of variants*:

no jealousy towards techempower's c++ frameworks 🙂

a test with D12.3 and i9900 cpu within windows server 2025, push the number of messages with sql query from 750 to 5000 for sec (MySQL 8.4.5** LTS)

(ab -n 10000 -c 1000 -k http://address/isapiscale.dll/scale) with 1000 concurrent users

document path: /isapi/isapiscale.dll/scale

document length: 2425 bytes

concurrency level: 1000

time taken for tests: 1.968 seconds

Complete requests: 10000

failed requests: 0

keep-alive requests: 10000

total transferred: 25950000 bytes

HTML transferred: 24250000 bytes

requests per second: 5081.92*** [#/sec] (mean)

(ubuntu 25.04 same vm and mysql config -> apache mod ~2500 reqs/s)

time per request: 196.776 [ms] (mean)

time per request: 0.197 [ms] (mean, across all concurrent requests)

transfer rate: 12878.49 [Kbytes/sec] received

this should increment linearly among all the cpu cores

• cast the type eg. Obj.S['one'] := 'thisisastring' Obj.I['two'] := 2

(string, integer, float, etc.)

** as client libs use libmysql.dll, libssl-3-x64.dll, libcrypto-3-x64.dll

*** identical score among MSHeap and RDPMM64 (tbbmalloc) allocators

btw. using mysql sample database world

let me know opinions or errors, kind regards

rdp@dellapasqua.com

Roberto