From 5618df3a8998d30cff594b3844f59fbc675ff66f Mon Sep 17 00:00:00 2001
From: Alex Kasko <alex@staticlibs.net>
Date: Wed, 22 Apr 2026 22:36:45 +0100
Subject: [PATCH] Fix two data races, add ThreadSan CI runs

This PR fixes two minor data races and adds thread sanitizer test runs
to CI.
---
 .github/workflows/IntegrationTests.yml       | 9 ++++++++-
 src/include/storage/postgres_table_entry.hpp | 2 +-
 src/postgres_scanner.cpp                     | 1 +
 src/storage/postgres_insert.cpp              | 2 +-
 src/storage/postgres_table_entry.cpp         | 7 ++++---
 5 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/IntegrationTests.yml b/.github/workflows/IntegrationTests.yml
index 80f30c449..7159e7e40 100644
--- a/.github/workflows/IntegrationTests.yml
+++ b/.github/workflows/IntegrationTests.yml
@@ -257,6 +257,10 @@ jobs:
     needs: linux-tests
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        threadsan: [0, 1]
+
     env:
       CMAKE_BUILD_PARALLEL_LEVEL: 2
       CC: 'ccache gcc'
@@ -286,7 +290,7 @@ jobs:
       working-directory: ./duckdb
       run: |
         DUCKDB_VERSION=$(git rev-parse --short HEAD)
-        KEY="${{ runner.os }}-${{ runner.arch }}-$DUCKDB_VERSION"-relassert
+        KEY="${{ runner.os }}-${{ runner.arch }}-$DUCKDB_VERSION"-relassert-${{ matrix.threadsan }}
         echo "value=${KEY}" >> "${GITHUB_OUTPUT}"
 
     - name: Restore Cache
@@ -311,8 +315,11 @@ jobs:
         vcpkgGitCommitId: 84bab45d415d22042bd0b9081aea57f362da3f35
 
     - name: Build extension
+      env:
+        THREADSAN: ${{ matrix.threadsan }}
       run: |
         make relassert
+        cat ./build/relassert/src/CMakeFiles/duckdb.dir/flags.make
         cd build
         ln -s relassert release
 
diff --git a/src/include/storage/postgres_table_entry.hpp b/src/include/storage/postgres_table_entry.hpp
index 02da22ff9..b97677c39 100644
--- a/src/include/storage/postgres_table_entry.hpp
+++ b/src/include/storage/postgres_table_entry.hpp
@@ -64,7 +64,7 @@ class PostgresTableEntry : public TableCatalogEntry {
 	//! We would in this case remap them to "ID" and "id:1", while postgres_names store the original names
 	vector<string> postgres_names;
 	//! The approximate number of pages a table consumes in Postgres
-	int64_t approx_num_pages;
+	std::atomic<int64_t> approx_num_pages;
 };
 
 } // namespace duckdb
diff --git a/src/postgres_scanner.cpp b/src/postgres_scanner.cpp
index 73023cfeb..6679746cd 100644
--- a/src/postgres_scanner.cpp
+++ b/src/postgres_scanner.cpp
@@ -451,6 +451,7 @@ static unique_ptr<LocalTableFunctionState> GetLocalState(ClientContext &context,
 	}
 	if (bind_data.pages_approx == 0 || bind_data.requires_materialization) {
 		PostgresInitInternal(context, &bind_data, *local_state, 0, POSTGRES_TID_MAX);
+		lock_guard<mutex> parallel_lock(gstate.lock);
 		gstate.page_idx = POSTGRES_TID_MAX;
 	} else if (!PostgresParallelStateNext(context, input.bind_data.get(), *local_state, gstate)) {
 		local_state->done = true;
diff --git a/src/storage/postgres_insert.cpp b/src/storage/postgres_insert.cpp
index 6b129061d..5310b1d53 100644
--- a/src/storage/postgres_insert.cpp
+++ b/src/storage/postgres_insert.cpp
@@ -141,7 +141,7 @@ SinkFinalizeType PostgresInsert::Finalize(Pipeline &pipeline, Event &event, Clie
 	idx_t bytes_per_page = 8192;
 	idx_t bytes_per_row = gstate.table.GetColumns().LogicalColumnCount() * 8;
 	idx_t rows_per_page = MaxValue<idx_t>(1, bytes_per_page / bytes_per_row);
-	gstate.table.approx_num_pages += gstate.insert_count / rows_per_page;
+	gstate.table.approx_num_pages.fetch_add(gstate.insert_count / rows_per_page, std::memory_order_acq_rel);
 	return SinkFinalizeType::READY;
 }
 
diff --git a/src/storage/postgres_table_entry.cpp b/src/storage/postgres_table_entry.cpp
index 0ce84c86a..a746a456b 100644
--- a/src/storage/postgres_table_entry.cpp
+++ b/src/storage/postgres_table_entry.cpp
@@ -18,14 +18,14 @@ PostgresTableEntry::PostgresTableEntry(Catalog &catalog, SchemaCatalogEntry &sch
 		postgres_types.push_back(PostgresUtils::CreateEmptyPostgresType(col.GetType()));
 		postgres_names.push_back(col.GetName());
 	}
-	approx_num_pages = 0;
+	approx_num_pages.store(0, std::memory_order_release);
 }
 
 PostgresTableEntry::PostgresTableEntry(Catalog &catalog, SchemaCatalogEntry &schema, PostgresTableInfo &info)
     : TableCatalogEntry(catalog, schema, *info.create_info), postgres_types(std::move(info.postgres_types)),
       postgres_names(std::move(info.postgres_names)) {
 	D_ASSERT(postgres_types.size() == columns.LogicalColumnCount());
-	approx_num_pages = info.approx_num_pages;
+	approx_num_pages.store(info.approx_num_pages, std::memory_order_release);
 }
 
 unique_ptr<BaseStatistics> PostgresTableEntry::GetStatistics(ClientContext &context, column_t column_id) {
@@ -54,7 +54,8 @@ TableFunction PostgresTableEntry::GetScanFunction(ClientContext &context, unique
 	result->names = postgres_names;
 	result->postgres_types = postgres_types;
 	result->read_only = transaction.IsReadOnly();
-	PostgresScanFunction::PrepareBind(pg_catalog.GetPostgresVersion(), context, *result, approx_num_pages);
+	PostgresScanFunction::PrepareBind(pg_catalog.GetPostgresVersion(), context, *result,
+	                                  approx_num_pages.load(std::memory_order_acquire));
 
 	bind_data = std::move(result);
 	auto function = PostgresScanFunction();