diff --git a/src/expire-config.hpp b/src/expire-config.hpp
index c4ae83b49..e6acf043c 100644
--- a/src/expire-config.hpp
+++ b/src/expire-config.hpp
@@ -43,6 +43,9 @@ struct expire_config_t
     /// Expire mode.
     expire_mode mode = expire_mode::full_area;
 
+    /// Do expire based on symmetric difference of old and new geometry
+    bool diff_expire = false;
+
 }; // struct expire_config_t
 
 #endif // OSM2PGSQL_EXPIRE_CONFIG_HPP
diff --git a/src/flex-lua-table.cpp b/src/flex-lua-table.cpp
index abb55ed1f..b88c58261 100644
--- a/src/flex-lua-table.cpp
+++ b/src/flex-lua-table.cpp
@@ -310,6 +310,15 @@ void parse_and_set_expire_options(lua_State *lua_state,
         }
         lua_pop(lua_state, 1); // "buffer"
 
+        lua_getfield(lua_state, -1, "diff_expire");
+        if (lua_isboolean(lua_state, -1)) {
+            config.diff_expire = lua_toboolean(lua_state, -1);
+        } else if (!lua_isnil(lua_state, -1)) {
+            throw std::runtime_error{
+                "Optional expire field 'diff_expire' must contain a boolean."};
+        }
+        lua_pop(lua_state, 1); // "diff_expire"
+
         // Actually add the expire only if we are in append mode.
         if (append_mode) {
             column->add_expire(config);
diff --git a/src/flex-table-column.cpp b/src/flex-table-column.cpp
index 205c44f09..90911eaf6 100644
--- a/src/flex-table-column.cpp
+++ b/src/flex-table-column.cpp
@@ -10,6 +10,8 @@
 #include "flex-table-column.hpp"
 
 #include "format.hpp"
+#include "geom-boost-adaptor.hpp"
+#include "overloaded.hpp"
 #include "pgsql-capabilities.hpp"
 #include "projection.hpp"
 #include "util.hpp"
@@ -208,18 +210,146 @@ void flex_table_column_t::add_expire(expire_config_t const &config)
     m_expires.push_back(config);
 }
 
+namespace {
+
+/**
+ * This expires all geometries in "geoms" by themselves. Used when we don't
+ * need diff expire.
+ */
+void separate_expire(std::vector<geom::geometry_t> const &geoms,
+                     expire_config_t const &expire_config,
+                     expire_tiles_t &expire_tiles,
+                     std::vector<expire_output_t> *expire_outputs)
+{
+    assert(expire_outputs);
+
+    for (auto const &geom : geoms) {
+        expire_tiles.from_geometry(geom, expire_config);
+    }
+    expire_tiles.commit_tiles(&expire_outputs->at(expire_config.expire_output));
+}
+
+/**
+ * When doing diff expire, we need to calculate the symmetric difference
+ * between old and new geometries. The difference is done by type, so points
+ * are compared with points, linestrings with linestrings, etc. This function
+ * separates out the input geometries by the three fundamental types.
+ */
+// NOLINTBEGIN(cppcoreguidelines-rvalue-reference-param-not-moved)
+template <typename T>
+void classify_geometries(T input_geoms, geom::multipoint_t *points,
+                         geom::multilinestring_t *linestrings,
+                         geom::multipolygon_t *polygons)
+{
+    assert(points);
+    assert(linestrings);
+    assert(polygons);
+
+    for (auto &&geom : *input_geoms) {
+        visit(overloaded{
+                  [&](geom::nullgeom_t && /*input*/) {},
+                  [&](geom::point_t &&input) { points->add_geometry(input); },
+                  [&](geom::linestring_t &&input) {
+                      linestrings->add_geometry(std::move(input));
+                  },
+                  [&](geom::polygon_t &&input) {
+                      polygons->add_geometry(std::move(input));
+                  },
+                  [&](geom::multipoint_t &&input) {
+                      for (auto &&point : input) {
+                          points->add_geometry(point);
+                      }
+                  },
+                  [&](geom::multilinestring_t &&input) {
+                      for (auto &&linestring : input) {
+                          linestrings->add_geometry(std::move(linestring));
+                      }
+                  },
+                  [&](geom::multipolygon_t &&input) {
+                      for (auto &&polygon : input) {
+                          polygons->add_geometry(std::move(polygon));
+                      }
+                  },
+                  [&](geom::collection_t &&input) {
+                      classify_geometries(&input, points, linestrings,
+                                          polygons);
+                  }},
+              std::move(geom));
+    }
+}
+// NOLINTEND(cppcoreguidelines-rvalue-reference-param-not-moved)
+
+template <typename T>
+void diff_and_expire(geom::multigeometry_t<T> const &old_geoms,
+                     geom::multigeometry_t<T> const &new_geoms,
+                     expire_config_t const &expire_config,
+                     expire_tiles_t &expire_tiles)
+{
+    std::vector<T> diffs;
+    boost::geometry::sym_difference(old_geoms, new_geoms, diffs);
+    for (auto const &geom : diffs) {
+        expire_tiles.from_geometry(geom, expire_config);
+    }
+}
+
+void diff_expire(std::vector<geom::geometry_t> *geoms_old,
+                 std::vector<geom::geometry_t> *geoms_new,
+                 expire_config_t const &expire_config,
+                 expire_tiles_t &expire_tiles,
+                 std::vector<expire_output_t> *expire_outputs)
+{
+    assert(geoms_old);
+    assert(geoms_new);
+    assert(expire_outputs);
+
+    geom::multipoint_t old_points;
+    geom::multilinestring_t old_linestrings;
+    geom::multipolygon_t old_polygons;
+
+    classify_geometries(geoms_old, &old_points, &old_linestrings,
+                        &old_polygons);
+
+    geom::multipoint_t new_points;
+    geom::multilinestring_t new_linestrings;
+    geom::multipolygon_t new_polygons;
+
+    classify_geometries(geoms_new, &new_points, &new_linestrings,
+                        &new_polygons);
+
+    diff_and_expire(old_points, new_points, expire_config, expire_tiles);
+    diff_and_expire(old_linestrings, new_linestrings, expire_config,
+                    expire_tiles);
+    diff_and_expire(old_polygons, new_polygons, expire_config, expire_tiles);
+
+    expire_tiles.commit_tiles(&expire_outputs->at(expire_config.expire_output));
+}
+
+} // anonymous namespace
+
 void flex_table_column_t::do_expire(
-    geom::geometry_t const &geom, std::vector<expire_tiles_t> *expire,
-    std::vector<expire_output_t> *expire_outputs) const
+    std::vector<geom::geometry_t> *geoms_old,
+    std::vector<geom::geometry_t> *geoms_new,
+    std::vector<expire_tiles_t> *expire,
+    std::vector<expire_output_t> *expire_outputs, bool enable_diff_expire) const
 {
+    assert(geoms_old);
+    assert(geoms_new);
     assert(expire);
     assert(expire_outputs);
 
     for (auto const &expire_config : m_expires) {
         assert(expire_config.expire_output < expire->size());
         auto &expire_tiles = expire->at(expire_config.expire_output);
-        expire_tiles.from_geometry(geom, expire_config);
-        expire_tiles.commit_tiles(
-            &expire_outputs->at(expire_config.expire_output));
+
+        if (!expire_config.diff_expire || !enable_diff_expire ||
+            geoms_old->empty() || geoms_new->empty()) {
+            separate_expire(*geoms_old, expire_config, expire_tiles,
+                            expire_outputs);
+            separate_expire(*geoms_new, expire_config, expire_tiles,
+                            expire_outputs);
+        } else {
+            diff_expire(geoms_old, geoms_new, expire_config, expire_tiles,
+                        expire_outputs);
+        }
     }
 }
diff --git a/src/flex-table-column.hpp b/src/flex-table-column.hpp
index 558ce29d0..cb9d367ad 100644
--- a/src/flex-table-column.hpp
+++ b/src/flex-table-column.hpp
@@ -18,6 +18,7 @@
 #include <cassert>
 #include <cstdint>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 enum class table_column_type : uint8_t
@@ -54,6 +55,8 @@ enum class table_column_type : uint8_t
     id_num
 };
 
+class geometry_cache_t;
+
 /**
  * A column in a flex_table_t.
  */
@@ -134,9 +137,11 @@ class flex_table_column_t
         return m_expires;
     }
 
-    void do_expire(geom::geometry_t const &geom,
+    void do_expire(std::vector<geom::geometry_t> *geoms_old,
+                   std::vector<geom::geometry_t> *geoms_new,
                    std::vector<expire_tiles_t> *expire,
-                   std::vector<expire_output_t> *expire_outputs) const;
+                   std::vector<expire_output_t> *expire_outputs,
+                   bool enable_diff_expire) const;
 
 private:
     std::vector<expire_config_t> m_expires;
@@ -170,6 +175,40 @@ class flex_table_column_t
 
     /// Column will be created but not filled by osm2pgsql.
     bool m_create_only = false;
-};
+}; // class flex_table_column_t
+
+/**
+ * While processing an OSM object, this cache is used to hold all old and all
+ * new geometries stored in all geometry columns with expire config in a table.
+ * Later those geometries are used to calculate the expire.
+ */
+class geometry_cache_t
+{
+public:
+    template <typename GEOM>
+    void add_old(flex_table_column_t const *column, GEOM &&geom)
+    {
+        m_geometries[column].first.push_back(std::forward<GEOM>(geom));
+    }
+
+    template <typename GEOM>
+    void add_new(flex_table_column_t const *column, GEOM &&geom)
+    {
+        m_geometries[column].second.push_back(std::forward<GEOM>(geom));
+    }
+
+    auto begin() noexcept { return m_geometries.begin(); }
+
+    auto end() noexcept { return m_geometries.end(); }
+
+    void clear() { m_geometries.clear(); }
+
+private:
+    std::unordered_map<
+        flex_table_column_t const *,
+        std::pair<std::vector<geom::geometry_t>, std::vector<geom::geometry_t>>>
+        m_geometries;
+
+}; // class geometry_cache_t
 
 #endif // OSM2PGSQL_FLEX_TABLE_COLUMN_HPP
diff --git a/src/flex-write.cpp b/src/flex-write.cpp
index f507eafe5..3e0883859 100644
--- a/src/flex-write.cpp
+++ b/src/flex-write.cpp
@@ -8,6 +8,7 @@
  */
 
 #include "flex-lua-geom.hpp"
+#include "flex-table-column.hpp"
 #include "flex-write.hpp"
 #include "geom-functions.hpp"
 #include "json-writer.hpp"
@@ -257,11 +258,9 @@ bool is_compatible(geom::geometry_t const &geom,
 
 } // anonymous namespace
 
-void flex_write_column(lua_State *lua_state,
+void flex_write_column(lua_State *lua_state, geometry_cache_t *geom_cache,
                        db_copy_mgr_t<db_deleter_by_type_and_id_t> *copy_mgr,
-                       flex_table_column_t const &column,
-                       std::vector<expire_tiles_t> *expire,
-                       std::vector<expire_output_t> *expire_outputs)
+                       flex_table_column_t const &column)
 {
     lua_getfield(lua_state, -1, column.name().c_str());
     int const ltype = lua_type(lua_state, -1);
@@ -446,13 +445,13 @@ void flex_write_column(lua_State *lua_state,
                      type == table_column_type::multilinestring ||
                      type == table_column_type::multipolygon);
                 if (geom->srid() == column.srid()) {
-                    column.do_expire(*geom, expire, expire_outputs);
                     copy_mgr->add_hex_geom(geom_to_ewkb(*geom, wrap_multi));
+                    geom_cache->add_new(&column, *geom);
                 } else {
                     auto const &proj = get_projection(column.srid());
-                    auto const tgeom = geom::transform(*geom, proj);
-                    column.do_expire(tgeom, expire, expire_outputs);
+                    auto tgeom = geom::transform(*geom, proj);
                     copy_mgr->add_hex_geom(geom_to_ewkb(tgeom, wrap_multi));
+                    geom_cache->add_new(&column, std::move(tgeom));
                 }
             } else {
                 write_null(copy_mgr, column);
diff --git a/src/flex-write.hpp b/src/flex-write.hpp
index bef1b45c0..dc2cb79cc 100644
--- a/src/flex-write.hpp
+++ b/src/flex-write.hpp
@@ -19,6 +19,7 @@
 #include <vector>
 
 class expire_tiles_t;
+class geometry_cache_t;
 
 class not_null_exception_t : public std::runtime_error
 {
@@ -34,10 +35,8 @@ class not_null_exception_t : public std::runtime_error
     flex_table_column_t const *m_column;
 }; // class not_null_exception_t
 
-void flex_write_column(lua_State *lua_state,
+void flex_write_column(lua_State *lua_state, geometry_cache_t *geom_cache,
                        db_copy_mgr_t<db_deleter_by_type_and_id_t> *copy_mgr,
-                       flex_table_column_t const &column,
-                       std::vector<expire_tiles_t> *expire,
-                       std::vector<expire_output_t> *expire_outputs);
+                       flex_table_column_t const &column);
 
 #endif // OSM2PGSQL_FLEX_WRITE_HPP
diff --git a/src/output-flex.cpp b/src/output-flex.cpp
index b8a41fbed..379e111d6 100644
--- a/src/output-flex.cpp
+++ b/src/output-flex.cpp
@@ -810,8 +810,8 @@ int output_flex_t::table_insert()
             } else if (column.type() == table_column_type::id_num) {
                 copy_mgr->add_column(id);
             } else {
-                flex_write_column(lua_state(), copy_mgr, column,
-                                  &m_expire_tiles, m_expire_outputs.get());
+                flex_write_column(lua_state(), &m_geometry_cache, copy_mgr,
+                                  column);
             }
         }
         table_connection.increment_insert_counter();
@@ -927,6 +927,7 @@ void output_flex_t::pending_way(osmid_t id)
     if (func) {
         get_mutex_and_call_lua_function(func, m_way_cache.get());
     }
+    expire_geoms_from_cache(true);
 }
 
 void output_flex_t::select_relation_members()
@@ -997,6 +998,7 @@ void output_flex_t::pending_relation(osmid_t id)
     select_relation_members();
     delete_from_tables(osmium::item_type::relation, id);
     process_relation();
+    expire_geoms_from_cache(true);
 }
 
 void output_flex_t::pending_relation_stage1c(osmid_t id)
@@ -1121,13 +1123,13 @@ void output_flex_t::node_add(osmium::Node const &node)
     auto const &func =
         node.tags().empty() ? m_process_untagged_node : m_process_node;
 
-    if (!func) {
-        return;
+    if (func) {
+        m_context_node = &node;
+        get_mutex_and_call_lua_function(func, node);
+        m_context_node = nullptr;
     }
 
-    m_context_node = &node;
-    get_mutex_and_call_lua_function(func, node);
-    m_context_node = nullptr;
+    expire_geoms_from_cache();
 }
 
 void output_flex_t::way_add(osmium::Way *way)
@@ -1137,12 +1139,12 @@ void output_flex_t::way_add(osmium::Way *way)
     auto const &func =
         way->tags().empty() ? m_process_untagged_way : m_process_way;
 
-    if (!func) {
-        return;
+    if (func) {
+        m_way_cache.init(way);
+        get_mutex_and_call_lua_function(func, m_way_cache.get());
     }
 
-    m_way_cache.init(way);
-    get_mutex_and_call_lua_function(func, m_way_cache.get());
+    expire_geoms_from_cache();
 }
 
 void output_flex_t::relation_add(osmium::Relation const &relation)
@@ -1150,13 +1152,13 @@ void output_flex_t::relation_add(osmium::Relation const &relation)
     auto const &func = relation.tags().empty() ? m_process_untagged_relation
                                                : m_process_relation;
 
-    if (!func) {
-        return;
+    if (func) {
+        m_relation_cache.init(relation);
+        select_relation_members();
+        get_mutex_and_call_lua_function(func, relation);
     }
 
-    m_relation_cache.init(relation);
-    select_relation_members();
-    get_mutex_and_call_lua_function(func, relation);
+    expire_geoms_from_cache();
 }
 
 void output_flex_t::delete_from_table(table_connection_t *table_connection,
@@ -1175,9 +1177,8 @@ void output_flex_t::delete_from_table(table_connection_t *table_connection,
             for (auto const &column : table_connection->table().columns()) {
                 if (column.has_expire()) {
                     for (int i = 0; i < num_tuples; ++i) {
-                        auto const geom = ewkb_to_geom(result.get(i, col));
-                        column.do_expire(geom, &m_expire_tiles,
-                                         m_expire_outputs.get());
+                        m_geometry_cache.add_old(
+                            &column, ewkb_to_geom(result.get(i, col)));
                     }
                     ++col;
                 }
@@ -1206,6 +1207,7 @@ void output_flex_t::node_delete(osmium::Node const &node)
     }
 
     node_delete(node.id());
+    expire_geoms_from_cache();
 }
 
 void output_flex_t::way_delete(osmium::Way *way)
@@ -1217,6 +1219,7 @@ void output_flex_t::way_delete(osmium::Way *way)
     }
 
     way_delete(way->id());
+    expire_geoms_from_cache();
 }
 
 void output_flex_t::relation_delete(osmium::Relation const &rel)
@@ -1227,6 +1230,7 @@ void output_flex_t::relation_delete(osmium::Relation const &rel)
     }
 
     relation_delete(rel.id());
+    expire_geoms_from_cache();
 }
 
 /* Delete is easy, just remove all traces of this object. We don't need to
@@ -1488,6 +1492,16 @@ void output_flex_t::init_lua(std::string const &filename,
     lua_remove(lua_state(), 1); // global "osm2pgsql"
 }
 
+void output_flex_t::expire_geoms_from_cache(bool enable_diff_expire)
+{
+    for (auto &[column, geoms] : m_geometry_cache) {
+        column->do_expire(&geoms.first, &geoms.second, &m_expire_tiles,
+                          m_expire_outputs.get(), enable_diff_expire);
+    }
+
+    m_geometry_cache.clear();
+}
+
 idlist_t const &output_flex_t::get_marked_node_ids()
 {
     if (m_stage2_node_ids->empty()) {
diff --git a/src/output-flex.hpp b/src/output-flex.hpp
index 7bbb6bef3..791aa0f1a 100644
--- a/src/output-flex.hpp
+++ b/src/output-flex.hpp
@@ -215,6 +215,13 @@ class output_flex_t : public output_t
 
     void delete_from_tables(osmium::item_type type, osmid_t osm_id);
 
+    /**
+     * Actually do expire from the geometries in the cache. Diff expire is
+     * only enabled in stage 1c, because we are only sure then that only the
+     * geometry changed and nothing else.
+     */
+    void expire_geoms_from_cache(bool enable_diff_expire = false);
+
     lua_State *lua_state() noexcept { return m_lua_state.get(); }
 
     void create_id_cache(flex_table_t const &table)
@@ -307,6 +314,9 @@ class output_flex_t : public output_t
     // accessed while protected using the lua_mutex.
     std::shared_ptr<lua_State> m_lua_state;
 
+    // Caches for old and new geometries from a single OSM object
+    geometry_cache_t m_geometry_cache;
+
     std::vector<expire_tiles_t> m_expire_tiles;
 
     way_cache_t m_way_cache;
diff --git a/tests/bdd/flex/expire-diff.feature b/tests/bdd/flex/expire-diff.feature
new file mode 100644
index 000000000..28f2d6254
--- /dev/null
+++ b/tests/bdd/flex/expire-diff.feature
@@ -0,0 +1,361 @@
+Feature: Diff expire
+
+    Scenario: non-diff expire way node changes with diff_expire disabled
+        Given the OSM data
+            """
+            n1 v1 x0 y0
+            n2 v1 x2 y0
+            n3 v1 x2 y1
+            n4 v1 x4 y1
+            w1 v1 Thighway=primary Nn1,n2,n3,n4
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_way_table('osm2pgsql_test', {
+                { column = 'geom', type = 'linestring', expire = {
+                        { output = eo, diff_expire = false }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_way(object)
+                the_table:insert{
+                    geom = object:as_linestring()
+                }
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,222638.98158654713 0,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            n2 v2 x0 y1
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,0 111325.14285463623,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 127 | 127 |
+            | 8    | 128 | 127 |
+            | 8    | 129 | 127 |
+            | 8    | 130 | 127 |
+            | 8    | 127 | 128 |
+            | 8    | 128 | 128 |
+            | 8    | 129 | 128 |
+
+    Scenario: non-diff expire if way changes
+        Given the OSM data
+            """
+            n1 v1 x0 y0
+            n2 v1 x2 y0
+            n3 v1 x2 y1
+            n4 v1 x4 y1
+            w1 v1 Thighway=primary Nn1,n2,n3,n4
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_way_table('osm2pgsql_test', {
+                { column = 'geom', type = 'linestring', expire = {
+                        { output = eo, diff_expire = true }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_way(object)
+                the_table:insert{
+                    geom = object:as_linestring()
+                }
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,222638.98158654713 0,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            w1 v2 Thighway=secondary Nn1,n2,n3,n4
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,222638.98158654713 0,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 127 | 127 |
+            | 8    | 128 | 127 |
+            | 8    | 129 | 127 |
+            | 8    | 130 | 127 |
+            | 8    | 127 | 128 |
+            | 8    | 128 | 128 |
+            | 8    | 129 | 128 |
+
+    Scenario: diff expire way node changes with diff_expire enabled
+        Given the OSM data
+            """
+            n1 v1 x0 y0
+            n2 v1 x2 y0
+            n3 v1 x2 y1
+            n4 v1 x4 y1
+            w1 v1 Thighway=primary Nn1,n2,n3,n4
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_way_table('osm2pgsql_test', {
+                { column = 'geom', type = 'linestring', expire = {
+                        { output = eo, diff_expire = true }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_way(object)
+                the_table:insert{
+                    geom = object:as_linestring()
+                }
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,222638.98158654713 0,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            n2 v2 x0 y1
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | way_id | geom!geo |
+            | 1      | 0 0,0 111325.14285463623,222638.98158654713 111325.14285463623,445277.96317309426 111325.14285463623 |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 127 | 127 |
+            | 8    | 128 | 127 |
+            | 8    | 129 | 127 |
+            | 8    | 127 | 128 |
+            | 8    | 128 | 128 |
+            | 8    | 129 | 128 |
+
+    Scenario: non-diff expire of relation when way changes with diff_expire disabled
+        Given the OSM data
+            """
+            n11 v1 x0 y0
+            n12 v1 x1 y0
+            n13 v1 x1 y1
+            n14 v1 x0 y1
+            n15 v1 x2 y2
+            n16 v1 x3 y2
+            n17 v1 x3 y3
+            n18 v1 x2 y3
+            w20 v1 Nn11,n12,n13,n14,n11
+            w21 v1 Nn15,n16,n17,n18,n15
+            r30 v1 Ttype=multipolygon Mw20@,w21@
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_relation_table('osm2pgsql_test', {
+                { column = 'geom', type = 'polygon', expire = {
+                        { output = eo, diff_expire = false }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_relation(object)
+                for geom in object:as_multipolygon():geometries() do
+                    the_table:insert{
+                        geom = geom
+                    }
+                end
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            w21 v2 Nn15,n16,n17,n15
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 127 | 127 |
+            | 8    | 128 | 127 |
+            | 8    | 127 | 128 |
+            | 8    | 128 | 128 |
+            | 8    | 129 | 125 |
+            | 8    | 130 | 125 |
+            | 8    | 129 | 126 |
+            | 8    | 130 | 126 |
+
+    Scenario: non-diff expire of relation when relation changes
+        Given the OSM data
+            """
+            n11 v1 x0 y0
+            n12 v1 x1 y0
+            n13 v1 x1 y1
+            n14 v1 x0 y1
+            n15 v1 x2 y2
+            n16 v1 x3 y2
+            n17 v1 x3 y3
+            n18 v1 x2 y3
+            w20 v1 Nn11,n12,n13,n14,n11
+            w21 v1 Nn15,n16,n17,n18,n15
+            r30 v1 Ttype=multipolygon Mw20@,w21@
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_relation_table('osm2pgsql_test', {
+                { column = 'geom', type = 'polygon', expire = {
+                        { output = eo, diff_expire = true }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_relation(object)
+                for geom in object:as_multipolygon():geometries() do
+                    the_table:insert{
+                        geom = geom
+                    }
+                end
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            r30 v2 Ttype=multipolygon,landuse=forest Mw20@,w21@
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 127 | 127 |
+            | 8    | 128 | 127 |
+            | 8    | 127 | 128 |
+            | 8    | 128 | 128 |
+            | 8    | 129 | 125 |
+            | 8    | 130 | 125 |
+            | 8    | 129 | 126 |
+            | 8    | 130 | 126 |
+
+    Scenario: non-diff expire of relation when way changes with diff_expire enabled
+        Given the OSM data
+            """
+            n11 v1 x0 y0
+            n12 v1 x1 y0
+            n13 v1 x1 y1
+            n14 v1 x0 y1
+            n15 v1 x2 y2
+            n16 v1 x3 y2
+            n17 v1 x3 y3
+            n18 v1 x2 y3
+            w20 v1 Nn11,n12,n13,n14,n11
+            w21 v1 Nn15,n16,n17,n18,n15
+            r30 Ttype=multipolygon Mw20@,w21@
+            """
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                table = 'osm2pgsql_test_expire',
+                maxzoom = 8,
+            })
+
+            local the_table = osm2pgsql.define_relation_table('osm2pgsql_test', {
+                { column = 'geom', type = 'polygon', expire = {
+                        { output = eo, diff_expire = true }
+                    }
+                },
+            })
+
+            function osm2pgsql.process_relation(object)
+                for geom in object:as_multipolygon():geometries() do
+                    the_table:insert{
+                        geom = geom
+                    }
+                end
+            end
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -c |
+        Then table osm2pgsql_test has 2 rows
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire has 0 rows
+
+        Given the OSM data
+            """
+            w21 v2 Nn15,n16,n17,n15
+            """
+        When running osm2pgsql flex with parameters
+            | --slim | -a |
+        Then table osm2pgsql_test contains exactly
+            | relation_id | geom!geo |
+            | 30          | (0 0,111319.49079327357 0,111319.49079327357 111325.14285463623,0 111325.14285463623,0 0) |
+            | 30          | (222638.98158654713 222684.20848178727,333958.4723798207 222684.20848178727,333958.4723798207 334111.17136656796,222638.98158654713 222684.20848178727) |
+        Then table osm2pgsql_test_expire contains exactly
+            | zoom |   x |   y |
+            | 8    | 129 | 125 |
+            | 8    | 130 | 125 |
+            | 8    | 129 | 126 |
+            | 8    | 130 | 126 |
+
diff --git a/tests/bdd/flex/lua-expire.feature b/tests/bdd/flex/lua-expire.feature
index fbff960ba..de4f25be3 100644
--- a/tests/bdd/flex/lua-expire.feature
+++ b/tests/bdd/flex/lua-expire.feature
@@ -220,6 +220,48 @@ Feature: Expire configuration in Lua file
         When running osm2pgsql flex
         Then table bar has 1562 rows
 
+    Scenario: Expire with diff_expire that's not a boolean fails
+        Given the input file 'liechtenstein-2013-08-03.osm.pbf'
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                filename = 'bar',
+                maxzoom = 12
+            })
+            osm2pgsql.define_node_table('bar', {
+                { column = 'some',
+                  type = 'geometry',
+                  expire = {
+                    { output = eo, diff_expire = 'foo' }
+                }}
+            })
+            """
+        When running osm2pgsql flex
+        Then execution fails
+        And the error output contains
+            """
+            Optional expire field 'diff_expire' must contain a boolean.
+            """
+
+    Scenario: Expire with diff_expire that's a boolean is okay
+        Given the input file 'liechtenstein-2013-08-03.osm.pbf'
+        And the lua style
+            """
+            local eo = osm2pgsql.define_expire_output({
+                filename = 'bar',
+                maxzoom = 12
+            })
+            osm2pgsql.define_node_table('bar', {
+                { column = 'some',
+                  type = 'geometry',
+                  expire = {
+                    { output = eo, diff_expire = true }
+                }}
+            })
+            """
+        When running osm2pgsql flex
+        Then execution is successful
+
     Scenario: Expire into table is okay
         Given the input file 'liechtenstein-2013-08-03.osm.pbf'
         And the lua style