*: followers in information_schema.placement_policies should show…

… default count when followers not set (pingcap#31927) close pingcap#31702
denimyftiu · Jan 25, 2022 · 172701c · 172701c
1 parent 8c5b04a
commit 172701c
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Showing 2 changed files with 10 additions and 4 deletions.
diff --git a/ddl/placement_policy_test.go b/ddl/placement_policy_test.go
@@ -399,15 +399,15 @@ func (s *testDBSuite6) TestAlterPlacementPolicy(c *C) {
 	// test for normal cases
 	tk.MustExec("alter placement policy x PRIMARY_REGION=\"bj\" REGIONS=\"bj,sh\"")
 	tk.MustQuery("show placement where target='POLICY x'").Check(testkit.Rows("POLICY x PRIMARY_REGION=\"bj\" REGIONS=\"bj,sh\" NULL"))
-	tk.MustQuery("select * from information_schema.placement_policies where policy_name = 'x'").Check(testkit.Rows(strconv.FormatInt(policy.ID, 10) + " def x bj bj,sh      0 0"))
+	tk.MustQuery("select * from information_schema.placement_policies where policy_name = 'x'").Check(testkit.Rows(strconv.FormatInt(policy.ID, 10) + " def x bj bj,sh      2 0"))
 	checkExistTableBundlesInPD(c, s.dom, "test", "tp")
 
 	tk.MustExec("alter placement policy x " +
 		"PRIMARY_REGION=\"bj\" " +
 		"REGIONS=\"bj\" " +
 		"SCHEDULE=\"EVEN\"")
 	tk.MustQuery("show placement where target='POLICY x'").Check(testkit.Rows("POLICY x PRIMARY_REGION=\"bj\" REGIONS=\"bj\" SCHEDULE=\"EVEN\" NULL"))
-	tk.MustQuery("select * from INFORMATION_SCHEMA.PLACEMENT_POLICIES WHERE POLICY_NAME='x'").Check(testkit.Rows(strconv.FormatInt(policy.ID, 10) + " def x bj bj     EVEN 0 0"))
+	tk.MustQuery("select * from INFORMATION_SCHEMA.PLACEMENT_POLICIES WHERE POLICY_NAME='x'").Check(testkit.Rows(strconv.FormatInt(policy.ID, 10) + " def x bj bj     EVEN 2 0"))
 	checkExistTableBundlesInPD(c, s.dom, "test", "tp")
 
 	tk.MustExec("alter placement policy x " +
@@ -435,7 +435,7 @@ func (s *testDBSuite6) TestAlterPlacementPolicy(c *C) {
 		"CATALOG_NAME,POLICY_NAME," +
 		"PRIMARY_REGION,REGIONS,CONSTRAINTS,LEADER_CONSTRAINTS,FOLLOWER_CONSTRAINTS,LEARNER_CONSTRAINTS," +
 		"SCHEDULE,FOLLOWERS,LEARNERS FROM INFORMATION_SCHEMA.placement_policies WHERE POLICY_NAME='x'").Check(
-		testkit.Rows("def x   [+disk=ssd]   [+region=sh]  0 3"),
+		testkit.Rows("def x   [+disk=ssd]   [+region=sh]  2 3"),
 	)
 	checkExistTableBundlesInPD(c, s.dom, "test", "tp")
 

diff --git a/executor/infoschema_reader.go b/executor/infoschema_reader.go
@@ -2884,6 +2884,12 @@ func (e *memtableRetriever) setDataFromPlacementPolicies(sctx sessionctx.Context
 		// also convert them to LeaderConstraints and FollowerConstraints
 		// for better user experience searching for particular constraints
 
+		// Followers == 0 means not set, so the default value 2 will be used
+		followerCnt := policy.PlacementSettings.Followers
+		if followerCnt == 0 {
+			followerCnt = 2
+		}
+
 		row := types.MakeDatums(
 			policy.ID,
 			infoschema.CatalogVal, // CATALOG
@@ -2895,7 +2901,7 @@ func (e *memtableRetriever) setDataFromPlacementPolicies(sctx sessionctx.Context
 			policy.PlacementSettings.FollowerConstraints,
 			policy.PlacementSettings.LearnerConstraints,
 			policy.PlacementSettings.Schedule,
-			policy.PlacementSettings.Followers,
+			followerCnt,
 			policy.PlacementSettings.Learners,
 		)
 		rows = append(rows, row)