planner: fix pessimistic-auto-commit not working for point plans (#39993

) (#40000)

close #39928

planner/core/point_get_plan.go

@@ -21,6 +21,7 @@ import (
  "strings"
 
  "github.com/pingcap/errors"
+ "github.com/pingcap/tidb/config"
  "github.com/pingcap/tidb/expression"
  "github.com/pingcap/tidb/infoschema"
  "github.com/pingcap/tidb/kv"
@@ -530,7 +531,7 @@ func getLockWaitTime(ctx sessionctx.Context, lockInfo *ast.SelectLockInfo) (lock
  // autocommit to 0. If autocommit is enabled, the rows matching the specification are not locked.
  // See https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
  sessVars := ctx.GetSessionVars()
- if !sessVars.IsAutocommit() || sessVars.InTxn() {
+ if !sessVars.IsAutocommit() || sessVars.InTxn() || config.GetGlobalConfig().PessimisticTxn.PessimisticAutoCommit.Load() {
  lock = true
  waitTime = sessVars.LockWaitTimeout
  if lockInfo.LockType == ast.SelectLockForUpdateWaitN {

tests/realtikvtest/pessimistictest/pessimistic_test.go

@@ -3108,13 +3108,21 @@ func TestPessimisticAutoCommitTxn(t *testing.T) {
 
  tk.MustExec("set tidb_txn_mode = 'pessimistic'")
  tk.MustExec("drop table if exists t")
- tk.MustExec("create table t (i int)")
+ tk.MustExec("create table t (i int primary key)")
  tk.MustExec("insert into t values (1)")
  tk.MustExec("set autocommit = on")
 
  rows := tk.MustQuery("explain update t set i = -i").Rows()
  explain := fmt.Sprintf("%v", rows[1])
  require.NotRegexp(t, ".*SelectLock.*", explain)
+ rows = tk.MustQuery("explain update t set i = -i where i = -1").Rows()
+ explain = fmt.Sprintf("%v", rows[1])
+ require.Regexp(t, ".*handle:-1.*", explain)
+ require.NotRegexp(t, ".*handle:-1, lock.*", explain)
+ rows = tk.MustQuery("explain update t set i = -i where i in (-1, 1)").Rows()
+ explain = fmt.Sprintf("%v", rows[1])
+ require.Regexp(t, ".*handle:\\[-1 1\\].*", explain)
+ require.NotRegexp(t, ".*handle:\\[-1 1\\].*, lock.*", explain)
 
  originCfg := config.GetGlobalConfig()
  defer config.StoreGlobalConfig(originCfg)
@@ -3125,6 +3133,12 @@ func TestPessimisticAutoCommitTxn(t *testing.T) {
  rows = tk.MustQuery("explain update t set i = -i").Rows()
  explain = fmt.Sprintf("%v", rows[1])
  require.Regexp(t, ".*SelectLock.*", explain)
+ rows = tk.MustQuery("explain update t set i = -i where i = -1").Rows()
+ explain = fmt.Sprintf("%v", rows[1])
+ require.Regexp(t, ".*handle:-1, lock.*", explain)
+ rows = tk.MustQuery("explain update t set i = -i where i in (-1, 1)").Rows()
+ explain = fmt.Sprintf("%v", rows[1])
+ require.Regexp(t, ".*handle:\\[-1 1\\].*, lock.*", explain)
 }
 
 func TestPessimisticLockOnPartition(t *testing.T) {