From cadb128f7edd89b48e089ba5cf555ae2d4c91632 Mon Sep 17 00:00:00 2001
From: Roland Teichert <roland@journeyapps.com>
Date: Thu, 9 Jan 2025 09:01:57 +0200
Subject: [PATCH 1/3] MySQL: Removed duplicate snapshot query stream invocation
 Added abortcontroller check during MySQL initial snapshot

---
 modules/module-mysql/src/replication/BinLogStream.ts | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/modules/module-mysql/src/replication/BinLogStream.ts b/modules/module-mysql/src/replication/BinLogStream.ts
index 483f292f9..59fd8309c 100644
--- a/modules/module-mysql/src/replication/BinLogStream.ts
+++ b/modules/module-mysql/src/replication/BinLogStream.ts
@@ -278,9 +278,7 @@ AND table_type = 'BASE TABLE';`,
         }
       );
       logger.info(`Initial replication done`);
-      await promiseConnection.query('COMMIT');
     } catch (e) {
-      await promiseConnection.query('ROLLBACK');
       throw e;
     } finally {
       connection.release();
@@ -305,12 +303,16 @@ AND table_type = 'BASE TABLE';`,
       columns = toColumnDescriptors(fields);
     });
 
-    for await (let row of query.stream()) {
+    for await (let row of stream) {
+      if (this.stopped) {
+        throw new Error('Abort signal received - initial replication interrupted.');
+      }
+
       if (columns == null) {
         throw new Error(`No 'fields' event emitted`);
       }
-      const record = common.toSQLiteRow(row, columns!);
 
+      const record = common.toSQLiteRow(row, columns!);
       await batch.save({
         tag: storage.SaveOperationTag.INSERT,
         sourceTable: table,

From c5705f467dcd4770c94e2e475b443fda2b1a80e5 Mon Sep 17 00:00:00 2001
From: Roland Teichert <roland@journeyapps.com>
Date: Thu, 9 Jan 2025 09:17:46 +0200
Subject: [PATCH 2/3] Added changeset

---
 .changeset/perfect-plums-cry.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/perfect-plums-cry.md

diff --git a/.changeset/perfect-plums-cry.md b/.changeset/perfect-plums-cry.md
new file mode 100644
index 000000000..b35b3c950
--- /dev/null
+++ b/.changeset/perfect-plums-cry.md
@@ -0,0 +1,5 @@
+---
+'@powersync/service-module-mysql': patch
+---
+
+Resolved excessive memory consumption during MySQL initial replication.

From 1bf04de9a23d3a205a280320e244a3626a0b9182 Mon Sep 17 00:00:00 2001
From: Roland Teichert <roland@journeyapps.com>
Date: Thu, 9 Jan 2025 09:29:01 +0200
Subject: [PATCH 3/3] Revert transaction commit and rollback

---
 modules/module-mysql/src/replication/BinLogStream.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/modules/module-mysql/src/replication/BinLogStream.ts b/modules/module-mysql/src/replication/BinLogStream.ts
index 59fd8309c..bf1b24a75 100644
--- a/modules/module-mysql/src/replication/BinLogStream.ts
+++ b/modules/module-mysql/src/replication/BinLogStream.ts
@@ -278,7 +278,9 @@ AND table_type = 'BASE TABLE';`,
         }
       );
       logger.info(`Initial replication done`);
+      await promiseConnection.query('COMMIT');
     } catch (e) {
+      await promiseConnection.query('ROLLBACK');
       throw e;
     } finally {
       connection.release();