*: add variables and support external timestamp read #38276

YangKeao · 2022-09-30T07:34:38Z

What problem does this PR solve?

Issue Number: close #38274

Problem Summary:

TiDB doesn't have a way to allow staleread with a timestamp from external (globally).

What is changed and how it works?

Add two variables to control the timestamp (tidb_external_ts) and whether to enable this feature (tidb_enable_external_ts_read)
If there is no explicitly stale-read (e.g. select as of, start transaction as of, set tidb_read_staleness...), and the control variable is on, use the external timestamp to perform stale read.

TODO:

Add variables
Implement basic function through modifying staleread
Add basic test about this function
Fine tune the context.Context. They are all context.TODO() now 😢 . But it can be a little difficult (as the variables hook deep-callchain doesn't pass in a context)
- Add context (context.Context) for planner preprocess #38359
- Add context (context.Context) for global variable get/set #38378
Add more unit tests / integration tests, especially with txn / stale-read.
Integrate with the real oracle api (or mocked oracle api)

Check List

Tests

Unit test
Integration test
Manual test (add detailed scripts or steps below)
No code

Side effects

Performance regression: Consumes more CPU
Performance regression: Consumes more Memory
Breaking backward compatibility

Documentation

Release note

Add two system variables `tidb_external_ts` and `tidb_enable_external_ts_read`. If the `tidb_enable_external_ts_read` is on, the tidb will be in read-only mode and read through the timestamp set in `tidb_external_ts`.

ti-chi-bot · 2022-09-30T07:34:39Z

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bb7133
lcwangchao

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ngaut · 2022-10-04T21:00:36Z

sessionctx/variable/session.go

@@ -1478,7 +1488,7 @@ func (connInfo *ConnectionInfo) IsSecureTransport() bool {
 }

 // NewSessionVars creates a session vars object.
-func NewSessionVars() *SessionVars {
+func NewSessionVars(hctx HookContext) *SessionVars {


Does it necessary to change the definition of NewSessionVars, which introduced so many changes.

Sadly, these changes have been merged into master in #38227. @morgo Provided a better way to work around this 👍 . I'll revert these changes after #38182 merged 😃

expression/builtin_time.go

bb7133

LGTM

planner/core/planbuilder.go

sessionctx/variable/sysvar.go

Signed-off-by: YangKeao <yangkeao@chunibyo.icu>

lcwangchao

LGTM

lcwangchao · 2022-11-01T09:15:47Z

/merge

ti-chi-bot · 2022-11-01T09:15:51Z

This pull request has been accepted and is ready to merge.

Commit hash: 24ba369

sre-bot · 2022-11-01T10:17:44Z

TiDB MergeCI notify

🔴 Bad News! New failing [1] after this pr merged.
These new failed integration tests seem to be caused by the current PR, please try to fix these new failed integration tests, thanks!

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-ddl-test	🟥 failed 1, success 5, total 6	28 min	New failing
idc-jenkins-ci/integration-cdc-test	🟢 all 38 tests passed	23 min	Existing passed
idc-jenkins-ci-tidb/integration-common-test	🟢 all 17 tests passed	18 min	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 11 tests passed	11 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	9 min 6 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	6 min 51 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	5 min 22 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	5 min 12 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 33 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed

YangKeao requested a review from a team as a code owner September 30, 2022 07:34

ti-chi-bot added release-note Denotes a PR that will be considered when it comes time to generate release notes. size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Sep 30, 2022

YangKeao marked this pull request as draft September 30, 2022 07:34

ti-chi-bot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Sep 30, 2022

YangKeao changed the title *: support external timestamp read for staleread *: add variables and support external timestamp read Sep 30, 2022

YangKeao force-pushed the external-timestamp-read branch 4 times, most recently from f7a8bc5 to 5e95ec2 Compare September 30, 2022 08:27

ti-chi-bot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 1, 2022

ngaut reviewed Oct 4, 2022

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YangKeao mentioned this pull request Oct 8, 2022

simplify SET GLOBAL code #33896

Closed

YangKeao force-pushed the external-timestamp-read branch from 5e95ec2 to be35ab7 Compare October 8, 2022 08:00

ti-chi-bot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Oct 8, 2022

YangKeao force-pushed the external-timestamp-read branch from be35ab7 to c642b43 Compare October 10, 2022 07:02

ti-chi-bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Oct 10, 2022

YangKeao force-pushed the external-timestamp-read branch 4 times, most recently from 81d76b6 to b8a1718 Compare October 12, 2022 09:24

ti-chi-bot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 12, 2022

asddongmen mentioned this pull request Oct 21, 2022

syncpoint (ticdc): support external ts read for TiCDC's downstream when syncpoint is enabled. pingcap/tiflow#7418

Merged

YangKeao force-pushed the external-timestamp-read branch from b8a1718 to 40737c0 Compare October 25, 2022 07:31

ti-chi-bot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Oct 25, 2022

YangKeao force-pushed the external-timestamp-read branch from 40737c0 to 720f4a3 Compare October 25, 2022 11:00

ti-chi-bot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Nov 1, 2022

This was referenced Nov 1, 2022

tidb: add document for external timestamp read pingcap/docs-cn#11583

Merged

tidb: add document for external timestamp read pingcap/docs#10783

Merged

YangKeao force-pushed the external-timestamp-read branch 2 times, most recently from b737ea8 to dabf247 Compare November 1, 2022 03:11

ti-chi-bot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Nov 1, 2022

YangKeao force-pushed the external-timestamp-read branch from dabf247 to f3282d9 Compare November 1, 2022 03:13

ti-chi-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 Nov 1, 2022

YangKeao force-pushed the external-timestamp-read branch from f3282d9 to d48f9c8 Compare November 1, 2022 03:49

YangKeao requested a review from lcwangchao November 1, 2022 03:51

bb7133 reviewed Nov 1, 2022

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bb7133 approved these changes Nov 1, 2022

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ti-chi-bot added status/LGT1 Indicates that a PR has LGTM 1. needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. labels Nov 1, 2022

YangKeao force-pushed the external-timestamp-read branch 2 times, most recently from db7b3ec to 445d678 Compare November 1, 2022 05:46

ti-chi-bot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Nov 1, 2022

lcwangchao reviewed Nov 1, 2022

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read from external timestamp

24ba369

Signed-off-by: YangKeao <yangkeao@chunibyo.icu>

YangKeao force-pushed the external-timestamp-read branch from 445d678 to 24ba369 Compare November 1, 2022 08:51

lcwangchao approved these changes Nov 1, 2022

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ti-chi-bot added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Nov 1, 2022

ti-chi-bot added the status/can-merge Indicates a PR has been approved by a committer. label Nov 1, 2022

Merge branch 'master' into external-timestamp-read

263fd85

ti-chi-bot merged commit ba6ae45 into pingcap:master Nov 1, 2022

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*: add variables and support external timestamp read #38276

*: add variables and support external timestamp read #38276

YangKeao commented Sep 30, 2022 •

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ti-chi-bot commented Sep 30, 2022 •

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ngaut Oct 4, 2022

YangKeao Oct 8, 2022

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lcwangchao commented Nov 1, 2022

ti-chi-bot commented Nov 1, 2022

sre-bot commented Nov 1, 2022

*: add variables and support external timestamp read #38276

*: add variables and support external timestamp read #38276

Conversation

YangKeao commented Sep 30, 2022 • edited Loading

What problem does this PR solve?

What is changed and how it works?

Check List

Release note

ti-chi-bot commented Sep 30, 2022 • edited Loading

ngaut Oct 4, 2022

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YangKeao Oct 8, 2022

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lcwangchao commented Nov 1, 2022

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TiDB MergeCI notify

YangKeao commented Sep 30, 2022 •

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