txn: update table delta map when really lock keys

[blacktear23]

What problem does this PR solve?

Issue Number: close #20975

Problem Summary:

mysql> drop table t2, t1;
Query OK, 0 rows affected (0.04 sec)

mysql> create table t1(a int);
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t1 values (1);
Query OK, 1 row affected (0.00 sec)

mysql> begin pessimistic;
Query OK, 0 rows affected (0.00 sec)

mysql> update t1 set a=a;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

/* session 2 */ mysql> create table t2(a int);
Query OK, 0 rows affected (0.00 sec)

mysql> commit;
ERROR 8028 (HY000): Information schema is changed during the execution of the statement(for example, table definition may be updated by other DDL ran in parallel). If you see this error often, try increasing `tidb_max_delta_schema_count`. [try again later]

What is changed and how it works?

What's Changed:
Update missing table ID to table delta map when there has key locked. And skip SchemaChecker when table delta map is empty.

Related changes

• No

Check List

Tests

• Unit test
• Integration test

Side effects

• Performance regression
  • Consumes more CPU

Release note

• txn: Fix missing table delta map track when query has locks.

[blacktear23]

@cfzjywxk PTAL

[cfzjywxk]

@you06 @MyonKeminta PTAL

[blacktear23]

@cfzjywxk Shall we cherry-pick it to master?

[cfzjywxk]

We need to add some cases for pointGetExec and batchPointGetExec

• Isolation is default RR(SI).
• Using non-handle unique keys.
• The correspond handle keys do not exist.
  These unique keys should be locked and thus these lock only transactions will get schema check during 2pc.

[blacktear23]

@cfzjywxk PTAL

[you06]

The schema check will be skipped here because the ddl lease is 0s.

tidb/domain/schema_validator.go

Lines 224 to 226 in e3b62d8

	if s.lease == 0 {
	return nil, ResultSucc
	}

[blacktear23]

The schema check will be skipped here because the ddl lease is 0s.

tidb/domain/schema_validator.go

Lines 224 to 226 in e3b62d8

	if s.lease == 0 {
	return nil, ResultSucc
	}

Is this has some problem? For tidb server the lease time should be 45s in configuration file. So seems this check always fails.

[you06]

The schema check will be skipped here because the ddl lease is 0s.

tidb/domain/schema_validator.go

Lines 224 to 226 in e3b62d8

	if s.lease == 0 {
	return nil, ResultSucc
	}

Is this has some problem? For tidb server the lease time should be 45s in configuration file. So seems this check always fails.

I think the problem comes here

tidb/executor/executor_test.go

Line 165 in e3b62d8

session.SetSchemaLease(0)

[cfzjywxk]

Maybe we could move the test cases to pessimistic_test.go and the lease is not zero.

[blacktear23]

Maybe we could move the test cases to pessimistic_test.go and the lease is not zero.

Good idea.

[blacktear23]

The schema check will be skipped here because the ddl lease is 0s.

tidb/domain/schema_validator.go

Lines 224 to 226 in e3b62d8

	if s.lease == 0 {
	return nil, ResultSucc
	}

Is this has some problem? For tidb server the lease time should be 45s in configuration file. So seems this check always fails.

I think the problem comes here

tidb/executor/executor_test.go

Line 165 in e3b62d8

session.SetSchemaLease(0)

Why those test case set lease to zero?

[you06]

No idea why changing default lease value, it does pollutes the test environment.

[you06]

LGTM

[cfzjywxk]

@lysu @jackysp PTAL

[jackysp]

LGTM

[lysu]

LGTM

[lysu]

@you06 PTAL need another LGTM

[cfzjywxk]

LGTM

[cfzjywxk]

/merge

[ti-srebot]

/run-all-tests

[blacktear23]

@cfzjywxk shall we cherry-pick it to master?