No description
Rongsong Shen
7519fa96dd
Root cause (found via live 3-node E2E + a verification test): lsn was 0-based
(hdr.lsn = current_lsn++ from current_lsn=0), and 0 was overloaded as a
sentinel, causing three cold-start defects on a freshly-promoted leader:
- the first WAL entry (own-term promotion NOOP at lsn 0) was structurally
uncommittable: commit_advance_locked only stores when cand>cur and
committed_lsn starts at 0, so lsn 0 can never advance it;
- commit_set_writable_lsn(noop_lsn=0) set writable_lsn=0, which wait_done
reads as 'gate off' — the own-term safety gate was a no-op on the first leader;
- bug-543 (WAL hole): ha_stream_wal_to_standby filters hdr.lsn>standby_lsn;
a fresh empty standby reports standby_lsn=0 (ambiguous 'empty' vs 'has lsn 0'),
so lsn 0 failed 0>0 and was dropped -> non-contiguous standby WAL.
Fix: a fresh persist store initializes current_lsn=1, reserving lsn 0 as the
none/empty sentinel. The first real entry is lsn 1 -> committable (0->1),
writable_lsn=1 -> gate effective, and standby_lsn=0 unambiguously means 'empty'
so catch-up streams from the first entry with no hole. persist_recover is
data-driven (current_lsn=max(hdr.lsn+1)), so existing on-disk WALs and non-fresh
recovery are unaffected; the change only sets the base for brand-new stores.
No wire/capnp change.
Verification: test_coldstart_lsn0 drives the real commit engine + real streamer
and proves H1 (first entry commits 0->1), H3 (gate effective + blocks when
committed<writable), H4 (empty-standby catch-up is contiguous [1,2], control
standby_lsn=1 gets only [2]). Full controller suite green under ASAN. Tests that
relied on the lsn-0 base were shifted (several strengthened); commit.c /
config_repl.c / ha.c / wire format untouched.
Owning specs: ha-commit-engine / ha-wal-replication / persist. Follow-up:
sweep stale lsn-0 comments (repl.c:429-436, persist.c:1055-1075/1240-1243/1296).
|
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|---|---|---|
| .claude | ||
| .kiro | ||
| .wolf | ||
| docs/superpowers/plans | ||
| ha/data | ||
| raft | ||
| src | ||
| .clang-format | ||
| .gitignore | ||
| CLAUDE.md | ||
| README.md | ||
1. commit 规则
- 每个人 fork 自己的 branch， 从自己的 branch 做 PR，review 完再 commit
2. code format
2.1. C
推荐使用 clang-format，公共配置放在源码里面 xce/.clang-format
（理论上直接使用源码里面 xce/.clang-format 文件格式不会变）
2.1.1. vscode 可以在配置中加上如下内容
"C_Cpp.clang_format_style": "WebKit",
"C_Cpp.clang_format_fallbackStyle": "WebKit",
2.1.2. vim & emacs
clang-format -style="{BasedOnStyle: webkit}" -i XX.c
2.2. golang
使用默认 gofmt
3. build environment and build (example of ubuntu)
3.1 build environment
- Install nix package management tool
sh <(curl -L https://nixos.org/nix/install) --daemon
- Edit /etc/nix/nix.conf to make sure
experimental-features = nix-command flakes
sandbox = true
sandbox-fallback = false
substituters = https://mirrors.ustc.edu.cn/nix-channels/store https://cache.nixos.org https://cache.nixos.org/
trusted-users = root <your account>
make sure that you have restarted nix-daemon service after you have changed /etc/nix/nix.conf
- Install socat and config ssh (for clone by ssh protocol)
nix profile add nixpkgs#socat
.ssh/config
Host gitea.shenrs.eu
HostName gitea.shenrs.eu
IdentityFile ~/.ssh/id_ed25519
ProxyCommand socat - openssl-connect:gitea.shenrs.eu:2022,snihost=gitea.shenrs.eu,verify=0
3.2 checkout source code
3.3 build (for package and release)
cd xce/src
# for build debug version
nix build --option sandbox false .#xcecore_debug
# for normal build
nix build --option sandbox false .#xcecore
You can find the generated binaries at =result= directory
3.4 build (for daily develop)
cd xce/src
nix develop
# using meson to generated build configuration (debug and address sanitize)
meson setup build --buildtype=debug -Db_sanitize=address
# run meson to build
meson compile -C build
# The generated files will be in build/
3.5 build AppImage package
cd xce/src
nix bundle --bundler github:ralismark/nix-appimage --option sandbox false .#xce
This will create all in one AppImage file which contains everything for package delivery.
4. misc
4.1. Windows remap ctrl and alt key
create a reg file, e.g. remapkey.reg
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout]
"Scancode Map"=hex:00,00,00,00,00,00,00,00,05,00,00,00,38,00,1d,00,1d,00,38,00,38,e0,1d,e0,1d,e0,38,e0,00,00,00,00
then double click remapkey.reg to import it. Restart OS.