planner: fix a sporadic panic due to the PR #7684 when using the prep…

…ared plan cache (#7956) (#8826)
pingcap · Dec 26, 2018 · 8b970d7 · 8b970d7
1 parent d805e83
commit 8b970d7
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Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/executor/prepared.go b/executor/prepared.go
@@ -128,6 +128,10 @@ func (e *PrepareExec) Next(ctx context.Context, chk *chunk.Chunk) error {
 	if _, ok := stmt.(ast.DDLNode); ok {
 		return ErrPrepareDDL
 	}
+	err = ResetContextOfStmt(e.ctx, stmt)
+	if err != nil {
+		return err
+	}
 	var extractor paramMarkerExtractor
 	stmt.Accept(&extractor)
 

diff --git a/tidb-server/main.go b/tidb-server/main.go
@@ -405,7 +405,8 @@ func setGlobalVars() {
 	variable.SysVars[variable.TIDBMemQuotaQuery].Value = strconv.FormatInt(cfg.MemQuotaQuery, 10)
 	variable.SysVars["lower_case_table_names"].Value = strconv.Itoa(cfg.LowerCaseTableNames)
 
-	plannercore.SetPreparedPlanCache(cfg.PreparedPlanCache.Enabled)
+	// For CI environment we default enable prepare-plan-cache.
+	plannercore.SetPreparedPlanCache(config.CheckTableBeforeDrop || cfg.PreparedPlanCache.Enabled)
 	if plannercore.PreparedPlanCacheEnabled() {
 		plannercore.PreparedPlanCacheCapacity = cfg.PreparedPlanCache.Capacity
 	}