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
- using a scalable allocator (see mine repositories)
- set keep-alive
- set max connections higher
- don't use globally unique firedac elements also saving time to recreate connections and queries, so:
- manage easy threadvar for database objects
- use database pooling
- 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
[email protected]
Roberto