From d9e2c7daf43ea69f56fb6cd67bde7e2ba9f5de19 Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Tue, 5 Oct 2021 15:19:21 +0200
Subject: [PATCH] cmd/ido2icingadb: reason not actually used INNER JOINs

---
 cmd/ido2icingadb/cache.go | 4 ++++
 cmd/ido2icingadb/main.go  | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/cmd/ido2icingadb/cache.go b/cmd/ido2icingadb/cache.go
index dfef5231..c6e24409 100644
--- a/cmd/ido2icingadb/cache.go
+++ b/cmd/ido2icingadb/cache.go
@@ -46,6 +46,8 @@ func buildEventTimeCache(ht *historyType, idoColumns []string) {
 		sliceIdoHistory(
 			ht.snapshot,
 			"SELECT "+strings.Join(idoColumns, ", ")+" FROM "+ht.idoTable+
+				// For actual migration icinga_objects will be joined anyway,
+				// so it makes no sense to take vanished objects into account.
 				" xh USE INDEX (PRIMARY) INNER JOIN icinga_objects o ON o.object_id=xh.object_id WHERE xh."+
 				ht.idoIdColumn+" > ? ORDER BY xh."+ht.idoIdColumn+" LIMIT ?",
 			nil, checkpoint.MaxId.Int64,
@@ -171,6 +173,8 @@ func buildPreviousHardStateCache(ht *historyType, idoColumns []string) {
 		sliceIdoHistory(
 			ht.snapshot,
 			"SELECT "+strings.Join(idoColumns, ", ")+" FROM "+ht.idoTable+
+				// For actual migration icinga_objects will be joined anyway,
+				// so it makes no sense to take vanished objects into account.
 				" xh USE INDEX (PRIMARY) INNER JOIN icinga_objects o ON o.object_id=xh.object_id WHERE xh."+
 				ht.idoIdColumn+" < ? ORDER BY xh."+ht.idoIdColumn+" DESC LIMIT ?",
 			nil, checkpoint,
diff --git a/cmd/ido2icingadb/main.go b/cmd/ido2icingadb/main.go
index 45aeb548..fafd51cd 100644
--- a/cmd/ido2icingadb/main.go
+++ b/cmd/ido2icingadb/main.go
@@ -175,6 +175,8 @@ func countIdoHistory() {
 	types.forEach(func(ht *historyType) {
 		err := ht.snapshot.Get(
 			&ht.total,
+			// For actual migration icinga_objects will be joined anyway,
+			// so it makes no sense to take vanished objects into account.
 			"SELECT COUNT(*) FROM "+ht.idoTable+" xh INNER JOIN icinga_objects o ON o.object_id=xh.object_id",
 		)
 		if err != nil {
@@ -199,6 +201,8 @@ func computeProgress(c *Config, idb *icingadb.DB) {
 
 		query := "SELECT xh." +
 			strings.Join(append(append([]string(nil), ht.idoColumns...), ht.idoIdColumn), ", xh.") + " id FROM " +
+			// For actual migration icinga_objects will be joined anyway,
+			// so it makes no sense to take vanished objects into account.
 			ht.idoTable + " xh USE INDEX (PRIMARY) INNER JOIN icinga_objects o ON o.object_id=xh.object_id WHERE " +
 			ht.idoIdColumn + " > ? ORDER BY xh." + ht.idoIdColumn + " LIMIT ?"