storage: expose etcd's transaction as LowLevelTxn interface to kv.Base #9016

MyonKeminta · 2025-01-20T10:14:20Z

What problem does this PR solve?

Issue Number: Ref #8978
Split out from #8989

What is changed and how does it work?

Exposes etcd's transactoin API to kv.Base layer. The behavior is also simulated in `MemKV` and `LevelDBKV` to provide the same interface.

Check List

Tests

Unit test

Code changes

Side effects

Increased code complexity

Related changes

Release note

None.

…te the behavior in memkv and leveldb Signed-off-by: MyonKeminta <[email protected]>

ti-chi-bot · 2025-01-20T10:14:23Z

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

Signed-off-by: MyonKeminta <[email protected]>

JmPotato

LGTM. Let's wait for #8919.

JmPotato · 2025-02-12T04:31:51Z

/retest

codecov · 2025-02-12T04:38:20Z

Codecov Report

Attention: Patch coverage is 80.20833% with 19 lines in your changes missing coverage. Please review.

Project coverage is 76.24%. Comparing base (daa23f8) to head (b7f7d12).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9016      +/-   ##
==========================================
+ Coverage   76.20%   76.24%   +0.03%     
==========================================
  Files         468      468              
  Lines       71546    71642      +96     
==========================================
+ Hits        54522    54623     +101     
+ Misses      13619    13606      -13     
- Partials     3405     3413       +8

Flag	Coverage Δ
unittests	`76.24% <80.20%> (+0.03%)`	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

rleungx · 2025-02-13T07:07:41Z

pkg/storage/kv/kv.go

+	If(conditions ...LowLevelTxnCondition) LowLevelTxn
+	Then(ops ...LowLevelTxnOp) LowLevelTxn
+	Else(ops ...LowLevelTxnOp) LowLevelTxn
+	Commit(ctx context.Context) (LowLevelTxnResult, error)


Do we need ctx?

When I'm writing the interface, consitering that ectd needs calling RPC when committing a transaction, I added it, but later I found etcd's API doesn't accept the context in its methods.
I'll remove it.

Signed-off-by: MyonKeminta <[email protected]>

rleungx · 2025-02-13T07:40:53Z

pkg/storage/kv/levedb_kv.go

@@ -147,3 +155,132 @@ func (txn *levelDBTxn) commit() error {

 	return txn.kv.Write(txn.batch, nil)
 }
+
+type levelDBLowLevelTxnSimulator struct {


Why name it *Simulator?

rleungx · 2025-02-13T07:53:47Z

pkg/storage/kv/levedb_kv.go

+
+	succeeds := true
+	for _, condition := range t.condition {
+		value, err := t.kv.DB.Get([]byte(condition.Key), nil)


I think kv.DB.Get is not right.

rleungx · 2025-02-13T07:55:07Z

pkg/storage/kv/levedb_kv.go

+			}
+		}
+
+		if !condition.CheckOnValue(valueStr, exists) {


Shall we use Has?

MyonKeminta · 2025-02-13T08:07:42Z

/hold

Signed-off-by: MyonKeminta <[email protected]>

…txn-interface

Signed-off-by: MyonKeminta <[email protected]>

rleungx · 2025-02-18T08:42:25Z

pkg/storage/kv/etcd_kv.go

+			// Put and delete operations of etcd's transaction won't return any previous data. Skip handling it.
+			resultItem = RawEtcdTxnResultItem{}
+			if put.PrevKv != nil {
+				key := strings.TrimPrefix(strings.TrimPrefix(string(put.PrevKv.Key), l.rootPath), "/")


Can we merge two trims?

I was just keeping the same way to write it as the existing code.
By the way this code can be removed as etcd's transaction api doesn't return the previous kv for Put ops. I removed it and updated only the rangeResp branch.

rleungx · 2025-02-18T08:45:18Z

pkg/storage/kv/kv.go

+}
+
+// CheckOnValue checks whether the condition is satisfied on the given value.
+func (c *RawEtcdTxnCondition) CheckOnValue(value string, exists bool) bool {


Where do we use it now?

No usage now. Removing it.

rleungx · 2025-02-18T08:49:41Z

pkg/storage/kv/kv.go

+// RawEtcdTxnResult represents the result of a RawEtcdTxn. The results of operations in `Then` or `Else` branches
+// will be listed in `ResultItems` in the same order as the operations are added.
+// For Put or Delete operations, its corresponding result is the previous value before writing.
+type RawEtcdTxnResult struct {


How about RawTxnResponse?

rleungx · 2025-02-18T08:49:56Z

pkg/storage/kv/kv.go

+	// * For Get operations, the result contains a key-value pair representing the get result. In case the key
+	//   does not exist, its `KeyValuePairs` field will be empty.
+	// * For GetRange operations, the result is a list of key-value pairs containing key-value paris that are scanned.
+	ResultItems []RawEtcdTxnResultItem


How about Responses?

rleungx · 2025-02-18T08:51:18Z

pkg/storage/kv/levedb_kv.go

@@ -80,6 +80,11 @@ func (kv *LevelDBKV) Remove(key string) error {
 	return errors.WithStack(kv.Delete([]byte(key), nil))
 }

+// CreateRawEtcdTxn implements kv.Base interface.
+func (*LevelDBKV) CreateRawEtcdTxn() RawEtcdTxn {


How about?

Suggested change

func (*LevelDBKV) CreateRawEtcdTxn() RawEtcdTxn {

func (*LevelDBKV) CreateRawTxn() RawEtcdTxn {

Signed-off-by: MyonKeminta <[email protected]>

MyonKeminta · 2025-02-18T09:24:34Z

/retest

ti-chi-bot · 2025-02-18T09:36:48Z

[LGTM Timeline notifier]

Timeline:

2025-02-12 06:01:55.148072924 +0000 UTC m=+422757.544294986: ☑️ agreed by JmPotato.
2025-02-18 09:36:47.457506008 +0000 UTC m=+954049.853728068: ☑️ agreed by rleungx.

ti-chi-bot · 2025-02-18T10:17:49Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JmPotato, rleungx

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rleungx · 2025-02-19T02:40:24Z

/unhold

rleungx · 2025-02-19T02:40:39Z

/retest

MyonKeminta · 2025-02-19T08:03:15Z

/retest

expose etcd's transaction as LowLevelTxn interface to kv.Base, simula…

7f34146

…te the behavior in memkv and leveldb Signed-off-by: MyonKeminta <[email protected]>

MyonKeminta marked this pull request as ready for review January 20, 2025 10:17

ti-chi-bot bot removed the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Jan 20, 2025

MyonKeminta added 2 commits January 21, 2025 14:22

Fix lint and add comments

413cc45

Signed-off-by: MyonKeminta <[email protected]>

fix errors.toml

29a8470

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JmPotato reviewed Jan 23, 2025

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fix typo

a93a181

Signed-off-by: MyonKeminta <[email protected]>

rleungx reviewed Feb 13, 2025

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pkg/storage/kv/levedb_kv.go Outdated

}

}

if !condition.CheckOnValue(valueStr, exists) {

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Shall we use Has?

ti-chi-bot bot added the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Feb 13, 2025

MyonKeminta added 6 commits February 17, 2025 18:05

Remove implementation to memory kv and leveldb kv

1edfa44

Signed-off-by: MyonKeminta <[email protected]>

Renaming

a927abf

Signed-off-by: MyonKeminta <[email protected]>

Adjust comments

d6bc730

Signed-off-by: MyonKeminta <[email protected]>

Remove unnecessary changes to mem_kv.go; adjust comments

e9cf2a1

Signed-off-by: MyonKeminta <[email protected]>

Merge branch 'master' of https://github.com/tikv/pd into m/low-level-…

2f1887b

…txn-interface

Fix lint

4fa3b5d

Signed-off-by: MyonKeminta <[email protected]>

rleungx reviewed Feb 18, 2025

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MyonKeminta added 2 commits February 18, 2025 17:08

Remove useless code; address comments

4f868de

Signed-off-by: MyonKeminta <[email protected]>

Remove mentions to etcd in the new raw transaction interface

13b3106

Signed-off-by: MyonKeminta <[email protected]>

ti-chi-bot bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. labels Feb 18, 2025

MyonKeminta requested a review from JmPotato February 18, 2025 09:36

rleungx approved these changes Feb 18, 2025

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JmPotato approved these changes Feb 18, 2025

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Merge branch 'master' into m/low-level-txn-interface

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ti-chi-bot bot merged commit 9336139 into tikv:master Feb 19, 2025
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MyonKeminta deleted the m/low-level-txn-interface branch February 19, 2025 08:22

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storage: expose etcd's transaction as LowLevelTxn interface to kv.Base #9016

storage: expose etcd's transaction as LowLevelTxn interface to kv.Base #9016

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MyonKeminta commented Feb 19, 2025

	func (*LevelDBKV) CreateRawEtcdTxn() RawEtcdTxn {
	func (*LevelDBKV) CreateRawTxn() RawEtcdTxn {

storage: expose etcd's transaction as LowLevelTxn interface to kv.Base #9016

storage: expose etcd's transaction as LowLevelTxn interface to kv.Base #9016

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MyonKeminta commented Jan 20, 2025 • edited Loading

What problem does this PR solve?

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Release note

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[LGTM Timeline notifier]

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