txn: add watermark

[GanZiheng]

Based on

• [dev] txn: implement watermark #57
• https://github.com/dgraph-io/badger/blob/45bca18f24ef5cc04701a1e17448ddfce9372da0/y/watermark.go

Signed-off-by: GanZiheng ganziheng98@gmail.com

[GanZiheng]

Will rebase onto master once #129 merged.

[GanZiheng]

A little bit weird, we will get thread sanitizer error if we use yatp. For example, https://github.com/tikv/agatedb/runs/6705381794?check_suite_focus=true.

[GanZiheng]

So I use standard library to spawn threads.

[skyzh]

https://github.com/tikv/agatedb/runs/6705381794?check_suite_focus=true

This is a known issue of crossbeam-epoch. If we want to use crossbeam channel in AgateDB, we will need to disable thread sanitizer check (or allow it to ignore crossbeam-related structures).

Few projects will run tests with sanitizers. I think we can periodically check address / leak / thread sanitizer when things go wrong, and simply remove sanitizer checks from CI.

[GanZiheng]

https://github.com/tikv/agatedb/runs/6705381794?check_suite_focus=true

This is a known issue of crossbeam-epoch. If we want to use crossbeam channel in AgateDB, we will need to disable thread sanitizer check (or allow it to ignore crossbeam-related structures).

Few projects will run tests with sanitizers. I think we can periodically check address / leak / thread sanitizer when things go wrong, and simply remove sanitizer checks from CI.

But when I use standard library to spawn thread, the issue disappears. Sort of strange...

[skyzh]

But when I use standard library to spawn thread, the issue disappears. Sort of strange...

Maybe by accident or some magic 🤪

[zhangjinpeng87]

@GanZiheng Please fix conflicts.

[codecov]

Codecov Report

Merging #132 (72e4742) into master (628064b) will increase coverage by 1.94%.
The diff coverage is 84.58%.

@@            Coverage Diff             @@
##           master     #132      +/-   ##
==========================================
+ Coverage   83.65%   85.60%   +1.94%     
==========================================
  Files          35       36       +1     
  Lines        6230     6753     +523     
==========================================
+ Hits         5212     5781     +569     
+ Misses       1018      972      -46     

[zhangjinpeng87]

LGTM

[Connor1996]

WaterMarkInner can be avoided, though LGTM

[Connor1996]

/merge