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planner: check the ignore-plan-cache hint in insert-stmt #40080

Merged
merged 13 commits into from
Dec 21, 2022
23 changes: 23 additions & 0 deletions planner/core/plan_cache_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,29 @@ func TestIssue38533(t *testing.T) {
tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
}

func TestIgnoreInsertStmt(t *testing.T) {
store := testkit.CreateMockStore(t)
tk := testkit.NewTestKit(t, store)
tk.MustExec("use test")
tk.MustExec("create table t (a int)")

// do not cache native insert-stmt
tk.MustExec("prepare st from 'insert into t values (1)'")
tk.MustExec("execute st")
tk.MustExec("execute st")
tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))

// ignore-hint in insert-stmt can work
tk.MustExec("prepare st from 'insert into t select * from t'")
tk.MustExec("execute st")
tk.MustExec("execute st")
tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
tk.MustExec("prepare st from 'insert /*+ ignore_plan_cache() */ into t select * from t'")
tk.MustExec("execute st")
tk.MustExec("execute st")
tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
}

func TestIssue38710(t *testing.T) {
store := testkit.CreateMockStore(t)
tk := testkit.NewTestKit(t, store)
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15 changes: 15 additions & 0 deletions planner/core/plan_cacheable_checker.go
Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,21 @@ func (checker *cacheableChecker) Enter(in ast.Node) (out ast.Node, skipChildren
return in, true
}
}
case *ast.InsertStmt:
if node.Select == nil {
// do not cache insert-values-stmt like 'insert into t values (...)' since
// no performance benefit and to save memory.
checker.cacheable = false
checker.reason = "ignore insert-values-stmt"
return in, true
}
for _, hints := range node.TableHints {
if hints.HintName.L == HintIgnorePlanCache {
checker.cacheable = false
checker.reason = "ignore plan cache by hint"
return in, true
}
}
case *ast.VariableExpr, *ast.ExistsSubqueryExpr, *ast.SubqueryExpr:
checker.cacheable = false
checker.reason = "query has sub-queries is un-cacheable"
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