cnid: sqlite-default residual cleanup; dsi: raise the listen backlog to 128

[andylemin]

CNID: sqlite-default residual cleanup

SQLite has been the default CNID scheme since PR #2265 ("Build and run netatalk without Berkeley DB") made meson select sqlite > mysql > dbd among the compiled backends — and all three compile by default, so DEFAULT_CNID_SCHEME, the runtime cnid scheme default, is already "sqlite" on any default build (afpd -v: "Default CNID backend: sqlite"). What remained was residue that still said dbd:

residue	fix
docker entrypoint fallback: cnid scheme = ${AFP_CNID_BACKEND:-dbd} (two sites)	:-sqlite — an unset AFP_CNID_BACKEND now matches what a stock source build already does
~30 CI test jobs (the ea:sys/ea:ad/UAM/AFP-version/login matrix) set no AFP_CNID_BACKEND and were unintentionally testing dbd via the entrypoint fallback	they now inherit sqlite, the shipped default — only jobs that intentionally test a backend name it. The "AFP spec test (cnid:dbd)" job, which also relied on the fallback, now sets -e AFP_CNID_BACKEND=dbd explicitly
man page never stated which backend is the default	the sqlite paragraph now says "This is the default backend when compiled in."
NEWS never recorded the default change	entry added

Intentional backend coverage is unchanged: the cnid:mysql legs (Alpine + Debian) and the cnid:sqlite/perf legs set AFP_CNID_BACKEND explicitly, the VM spectest script exports dbd explicitly, and the cnid:dbd job is now pinned. Every other job had no business running dbd; this PR resolves that unintended coverage skew — the broad matrix now tests what ships.

DSI: raise the listen backlog to 128

DSI_TCPMAXPEND has been 20 since the CVS-era initial revision, with no config knob. A reconnect storm (default 200 max connections) overflows a backlog of 20: dropped SYNs and ~1s client retransmit delays. 128 matches the common SOMAXCONN floor, and the kernel silently caps the effective backlog at net.core.somaxconn, so no new option is warranted. No steady-state effect; the #ifndef guard stays for build-time overrides.

Testing

• meson test (Alpine container, CI build flags): 3/3 suites, zero failures.
• AFP spectest ea=sys and ea=ad legs run without AFP_CNID_BACKEND — i.e. on the new sqlite fallback end-to-end: both exit 0, zero failures.
• Entrypoint verification: a container pinned to AFP_CNID_BACKEND=dbd generates cnid scheme = dbd and runs the cnid daemon; an env-less container generates cnid scheme = sqlite.
• afpd -v in the built image reports sqlite as the default backend.

Outstanding issue

The netatalk master still starts cnid_metad whenever the dbd backend is merely compiled in, so an env-less (sqlite) container runs an idle cnid daemon that nothing talks to. Startup should be conditional on a volume actually using cnid scheme = dbd — tracked in #3268.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

📊 Performance Dashboard

Commit: 6aa912a5545b11444152ac6214ecce8b50421119

🔥 Spectest (AFP 3.4) - FlameGraph

Netatalk Code-time: 2.8% · Runtime: 62s · Stacks: 1017

🔥 Click the preview to open the interactive flamegraph (zoom + search).

🔝 Top 10 leaf functions

Function	Samples
[libsqlite3.so.3.53.4]	262403330
do_syscall_64	192943625
_raw_spin_unlock_irqrestore	175303065
__cp_end	87100265
copy_folio_from_iter_atomic	81587590
x64_sys_call	52921680
afpd	46306470
srso_alias_safe_ret	30870980
perf_syscall_enter	28665910
vfs_writev	27563375

📈 Speedtest (AFP 3.4) - PerfGraph

Peak Read: 6830 MB/s (-6.1% vs hist avg 7271.0 MB/s; min 5963 / max 9526 over 25 PRs)
Peak Write: 1659 MB/s (+40.5% vs hist avg 1181.0 MB/s; min 225 / max 1808 over 25 PRs)

🔝 Throughputs per operation (vs. historical average)

Metric	Current (MB/s)	Cur Avg Δ%	Hist avg	Hist min	Hist max
Read peak mean	6830	-6.1%	7271.0	5963	9526
Read avg mean	3838	-8.6%	4197.7	3524	5393
Read avg max	4204	-9.5%	4647.8	3812	5932
Write peak mean	1659	+40.5%	1181.0	225	1808
Write avg mean	542	+35.9%	398.8	91	563
Write avg max	956	+35.0%	708.3	224	962
Copy peak mean	2508	-5.3%	2649.7	2294	3353
Copy avg mean	1512	-3.5%	1567.2	1360	1954
Copy avg max	1635	-4.8%	1717.5	1515	2087
ServerCopy peak mean	3405	-8.2%	3711.2	3055	5090
ServerCopy avg mean	1862	-3.8%	1936.4	1604	2501
ServerCopy avg max	1904	-5.6%	2017.3	1675	2658

⏱️ Lantest (AFP 3.4) - LatencyGraph

Avg total runtime: 3934 ms (-8.9% vs hist avg 4319.3 ms; min 2492 / max 5208 over 25 PRs)
Avg time per AFP op: 79 µs (-8.9% vs hist avg 86.7 µs; min 51 / max 105 over 25 PRs)

🐢 All operations (avg runtime, in test order, vs. historical average)

Metric	Current (ms)	Cur Avg Δ%	Adj Δ%	Hist avg	Hist min	Hist max
Writing one large file	35	-4.0%	—	36.4	26	41
Reading one large file	16	+4.2%	—	15.4	12	19
Creating 2000 files	485	-6.8%	+1.8%	520.6	259	831
Create 2000 dirs tree (20×9×10)	469	-9.5%	-0.9%	518.4	295	796
Open, write 1024 bytes, close 2000 files	335	-10.7%	-2.0%	375.0	244	459
Open, read 1024 bytes, close 2000 files	293	-10.5%	-1.9%	327.4	214	408
Copying 1000 files client-side (R+W)	519	-8.0%	+0.7%	564.0	322	677
Copying 2000 files server-side	487	-8.2%	+0.5%	530.4	212	727
Stat (lookup+getparams) 2000 files	190	-14.7%	-6.0%	222.7	152	282
Enumerate dir with 2000 files	12	+43.5%	+52.2%	8.36	3	14
Lock then unlock 2000 open forks	149	-8.7%	+0.0%	163.1	118	199
Deleting 2000 files	321	-8.1%	+0.5%	349.4	144	447
Byte-range lock/unlock 2000 ranges in one fork	156	-6.5%	+2.2%	166.8	124	196
Directory cache hits (20 dirs x 100 files)	86	-13.4%	-4.7%	99.3	67	122
Mixed cache operations (create/stat/enum/delete) on 500 files	205	-7.2%	+1.5%	220.9	111	265
Deep path traversal (20 levels x 100 walks)	92	-12.9%	-4.3%	105.7	73	131
Cache validation (500 files x 4 lookups)	84	-11.9%	-3.3%	95.4	66	116

Run baseline: median op-test delta -8.7%, MAD 1.9%. Adj Δ% shifts each delta by the median; standouts ≥5% in bold. A large MAD means the run did not move uniformly — read the adjusted column with caution.

[andylemin]

@rdmark ready for review