From d0cda1b47911f4b0e0ff335b730db85a1478cf7f Mon Sep 17 00:00:00 2001
From: Silvan <silvan.reusser@gmail.com>
Date: Tue, 27 Jun 2023 11:56:17 +0200
Subject: [PATCH] fix(migration): speed up step 11 (#6086)

---
 cmd/setup/11.go                   | 46 ++++++-------------------------
 cmd/setup/11/11_fetch_events.sql  | 12 --------
 cmd/setup/11/11_fill_column.sql   |  1 -
 cmd/setup/11/11_update_events.sql | 21 ++++++++++++++
 4 files changed, 29 insertions(+), 51 deletions(-)
 delete mode 100644 cmd/setup/11/11_fetch_events.sql
 delete mode 100644 cmd/setup/11/11_fill_column.sql
 create mode 100644 cmd/setup/11/11_update_events.sql

diff --git a/cmd/setup/11.go b/cmd/setup/11.go
index 544188d126..917f479e06 100644
--- a/cmd/setup/11.go
+++ b/cmd/setup/11.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"embed"
-	"time"
 
 	"github.com/cockroachdb/cockroach-go/v2/crdb"
 	"github.com/zitadel/logging"
@@ -15,10 +14,8 @@ import (
 var (
 	//go:embed 11/11_add_column.sql
 	addEventCreatedAt string
-	//go:embed 11/11_fetch_events.sql
-	fetchCreatedAt string
-	//go:embed 11/11_fill_column.sql
-	fillCreatedAt string
+	//go:embed 11/11_update_events.sql
+	setCreatedAt string
 	//go:embed 11/11_set_column.sql
 	setCreatedAtDetails string
 	//go:embed 11/postgres/create_index.sql
@@ -55,49 +52,22 @@ func (mig *AddEventCreatedAt) Execute(ctx context.Context) error {
 		return err
 	}
 
-	for {
-		var count int
+	for i := 0; ; i++ {
+		var affected int64
 		err = crdb.ExecuteTx(ctx, mig.dbClient.DB, nil, func(tx *sql.Tx) error {
-			rows, err := tx.Query(fetchCreatedAt, mig.BulkAmount)
+			res, err := tx.Exec(setCreatedAt, mig.BulkAmount)
 			if err != nil {
 				return err
 			}
-			defer rows.Close()
-
-			data := make(map[string]time.Time, 20)
-			for rows.Next() {
-				count++
-				var (
-					id           string
-					creationDate time.Time
-				)
-
-				err = rows.Scan(&id, &creationDate)
-				if err != nil {
-					return err
-				}
-
-				data[id] = creationDate
-
-			}
-			if err := rows.Err(); err != nil {
-				return err
-			}
-
-			for id, creationDate := range data {
-				_, err = tx.Exec(fillCreatedAt, creationDate, id)
-				if err != nil {
-					return err
-				}
-			}
 
+			affected, _ = res.RowsAffected()
 			return nil
 		})
 		if err != nil {
 			return err
 		}
-		logging.WithFields("count", count).Info("creation dates set")
-		if count < 20 {
+		logging.WithFields("step", "11", "iteration", i, "affected", affected).Info("set created_at iteration done")
+		if affected < int64(mig.BulkAmount) {
 			break
 		}
 	}
diff --git a/cmd/setup/11/11_fetch_events.sql b/cmd/setup/11/11_fetch_events.sql
deleted file mode 100644
index f668826751..0000000000
--- a/cmd/setup/11/11_fetch_events.sql
+++ /dev/null
@@ -1,12 +0,0 @@
-SELECT 
-    id
-    , creation_date 
-FROM 
-    eventstore.events 
-WHERE 
-    created_at IS NULL 
-ORDER BY 
-    event_sequence DESC
-    , instance_id 
-LIMIT $1 
-FOR UPDATE
\ No newline at end of file
diff --git a/cmd/setup/11/11_fill_column.sql b/cmd/setup/11/11_fill_column.sql
deleted file mode 100644
index 0a16913db4..0000000000
--- a/cmd/setup/11/11_fill_column.sql
+++ /dev/null
@@ -1 +0,0 @@
-UPDATE eventstore.events SET created_at = $1 WHERE id = $2
\ No newline at end of file
diff --git a/cmd/setup/11/11_update_events.sql b/cmd/setup/11/11_update_events.sql
new file mode 100644
index 0000000000..15a3df8a07
--- /dev/null
+++ b/cmd/setup/11/11_update_events.sql
@@ -0,0 +1,21 @@
+UPDATE eventstore.events SET 
+    created_at =  creation_date 
+FROM (
+    SELECT 
+        e.event_sequence as seq
+        , e.instance_id as i_id
+        , e.creation_date as cd
+    FROM 
+        eventstore.events e
+    WHERE 
+        created_at IS NULL
+    ORDER BY 
+        event_sequence ASC
+        , instance_id 
+    LIMIT $1
+) AS e 
+WHERE 
+    e.seq = eventstore.events.event_sequence 
+    AND e.i_id = eventstore.events.instance_id 
+    AND e.cd = eventstore.events.creation_date
+;
\ No newline at end of file