From 670a265c8e108995ce8cefef2036e9d384abb8c4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Rafael?= <joao.rafael@upperdelta.com>
Date: Tue, 10 Mar 2026 10:12:48 +0000
Subject: [PATCH] Fix sqlite delete hang by deferring rowid deletes

---
 src/storage/sqlite_delete.cpp                 | 27 +++++++++-----
 .../sql/storage/attach_delete_hang_repro.test | 36 +++++++++++++++++++
 2 files changed, 55 insertions(+), 8 deletions(-)
 create mode 100644 test/sql/storage/attach_delete_hang_repro.test

diff --git a/src/storage/sqlite_delete.cpp b/src/storage/sqlite_delete.cpp
index 8b28385..2409c46 100644
--- a/src/storage/sqlite_delete.cpp
+++ b/src/storage/sqlite_delete.cpp
@@ -6,6 +6,7 @@
 #include "storage/sqlite_transaction.hpp"
 #include "sqlite_db.hpp"
 #include "sqlite_stmt.hpp"
+#include <mutex>
 
 namespace duckdb {
 
@@ -25,7 +26,10 @@ class SQLiteDeleteGlobalState : public GlobalSinkState {
 
 	SQLiteTableEntry &table;
 	SQLiteStatement statement;
+	std::mutex rowid_lock;
+	vector<row_t> rowids;
 	idx_t delete_count;
+	bool delete_done = false;
 };
 
 string GetDeleteSQL(const string &table_name) {
@@ -38,9 +42,7 @@ string GetDeleteSQL(const string &table_name) {
 unique_ptr<GlobalSinkState> SQLiteDelete::GetGlobalSinkState(ClientContext &context) const {
 	auto &sqlite_table = table.Cast<SQLiteTableEntry>();
 
-	auto &transaction = SQLiteTransaction::Get(context, sqlite_table.catalog);
 	auto result = make_uniq<SQLiteDeleteGlobalState>(sqlite_table);
-	result->statement = transaction.GetDB().Prepare(GetDeleteSQL(sqlite_table.name));
 	return std::move(result);
 }
 
@@ -53,12 +55,8 @@ SinkResultType SQLiteDelete::Sink(ExecutionContext &context, DataChunk &chunk, O
 	chunk.Flatten();
 	auto &row_identifiers = chunk.data[row_id_index];
 	auto row_data = FlatVector::GetData<row_t>(row_identifiers);
-	for (idx_t i = 0; i < chunk.size(); i++) {
-		gstate.statement.Bind<int64_t>(0, row_data[i]);
-		gstate.statement.Step();
-		gstate.statement.Reset();
-	}
-	gstate.delete_count += chunk.size();
+	std::lock_guard<std::mutex> lock(gstate.rowid_lock);
+	gstate.rowids.insert(gstate.rowids.end(), row_data, row_data + chunk.size());
 	return SinkResultType::NEED_MORE_INPUT;
 }
 
@@ -67,6 +65,19 @@ SinkResultType SQLiteDelete::Sink(ExecutionContext &context, DataChunk &chunk, O
 //===--------------------------------------------------------------------===//
 SourceResultType SQLiteDelete::GetDataInternal(ExecutionContext &context, DataChunk &chunk, OperatorSourceInput &input) const {
 	auto &insert_gstate = sink_state->Cast<SQLiteDeleteGlobalState>();
+	if (!insert_gstate.delete_done) {
+		if (!insert_gstate.statement.IsOpen()) {
+			auto &transaction = SQLiteTransaction::Get(context.client, insert_gstate.table.catalog);
+			insert_gstate.statement = transaction.GetDB().Prepare(GetDeleteSQL(insert_gstate.table.name));
+		}
+		for (auto row_id : insert_gstate.rowids) {
+			insert_gstate.statement.Bind<int64_t>(0, row_id);
+			insert_gstate.statement.Step();
+			insert_gstate.statement.Reset();
+		}
+		insert_gstate.delete_count = insert_gstate.rowids.size();
+		insert_gstate.delete_done = true;
+	}
 	chunk.SetCardinality(1);
 	chunk.SetValue(0, 0, Value::BIGINT(insert_gstate.delete_count));
 
diff --git a/test/sql/storage/attach_delete_hang_repro.test b/test/sql/storage/attach_delete_hang_repro.test
new file mode 100644
index 0000000..f54f095
--- /dev/null
+++ b/test/sql/storage/attach_delete_hang_repro.test
@@ -0,0 +1,36 @@
+# name: test/sql/storage/attach_delete_hang_repro.test
+# description: reproduce large full-table delete behavior on attached SQLite table
+# group: [sqlite_storage]
+
+require sqlite_scanner
+
+statement ok
+SET threads=8
+
+statement ok
+ATTACH '__TEST_DIR__/attach_delete_hang_repro.db' AS s (TYPE SQLITE)
+
+statement ok
+CREATE TABLE s.t(i BIGINT, p VARCHAR, b BOOLEAN, ts TIMESTAMPTZ);
+
+query I
+INSERT INTO s.t
+SELECT i, 'f/' || i::VARCHAR || '.parquet', TRUE, now()
+FROM range(50000) t(i);
+----
+50000
+
+query I
+SELECT COUNT(*) FROM s.t;
+----
+50000
+
+query I
+DELETE FROM s.t;
+----
+50000
+
+query I
+SELECT COUNT(*) FROM s.t;
+----
+0