ST_Length(MULTILINESTRING)

Author: shtilman

QueryEngine/ExtensionFunctionsGeo.hpp

@@ -1175,6 +1175,36 @@ double ST_Length_LineString_Geodesic(int8_t* coords,
   return length_linestring(coords, coords_sz, ic, isr, osr, true, false);
 }
 
+EXTENSION_NOINLINE
+double ST_Length_MultiLineString(int8_t* coords,
+                                 int64_t coords_sz,
+                                 int8_t* linestring_sizes_in,
+                                 int64_t linestring_sizes_sz,
+                                 int32_t ic,
+                                 int32_t isr,
+                                 int32_t osr) {
+  if (linestring_sizes_sz <= 0) {
+    return 0.0;
+  }
+  double mls_length = 0.0;
+
+  auto next_linestring_coords = coords;
+
+  for (auto l = 0; l < linestring_sizes_sz; l++) {
+    auto linestring_coords = next_linestring_coords;
+    auto linestring_sizes = reinterpret_cast<int32_t*>(linestring_sizes_in);
+    auto linestring_num_points = linestring_sizes[l];
+    auto linestring_num_coords = 2 * linestring_num_points;
+    auto linestring_coords_size = linestring_num_coords * compression_unit_size(ic);
+    next_linestring_coords += linestring_coords_size;
+    double ls_length = length_linestring(
+        linestring_coords, linestring_coords_size, ic, isr, osr, false, false);
+    mls_length += ls_length;
+  }
+
+  return mls_length;
+}
+
 //
 // ST_Perimeter
 //

QueryEngine/GeoIR.cpp

@@ -73,6 +73,7 @@ std::vector<llvm::Value*> CodeGenerator::codegenGeoColumnVar(
   switch (ti.get_type()) {
     case kPOINT:
     case kLINESTRING:
+    case kMULTILINESTRING:
     case kPOLYGON:
     case kMULTIPOLYGON: {
       std::vector<llvm::Value*> geo_lvs;

QueryEngine/RelAlgTranslatorGeo.cpp

@@ -1210,20 +1210,34 @@ std::shared_ptr<Analyzer::Expr> RelAlgTranslator::translateUnaryGeoFunction(
     }
   }
 
-  // All geo function calls translated below only need the coords, extras e.g.
-  // ring_sizes are dropped. Specialize for other/new functions if needed.
-  geoargs.erase(geoargs.begin() + 1, geoargs.end());
+  // Unless overriden, function is assumed to be interested in the first geoarg only,
+  // which may be a geo object (e.g. geo column), or a coord array (e.g. geo literal)
+  auto discard_after_arg = 1;
 
   if (rex_function->getName() == "ST_Length"sv) {
-    if (arg_ti.get_type() != kLINESTRING) {
-      throw QueryNotSupported(rex_function->getName() + " expects LINESTRING");
+    if (arg_ti.get_type() != kLINESTRING && arg_ti.get_type() != kMULTILINESTRING) {
+      throw QueryNotSupported(rex_function->getName() +
+                              " expects LINESTRING or MULTILINESTRING");
+    }
+    if (arg_ti.get_type() == kMULTILINESTRING) {
+      auto ti0 = geoargs[0]->get_type_info();
+      if (ti0.get_type() == kARRAY && ti0.get_subtype() == kTINYINT) {
+        // Received expanded geo: widen the reach to grab linestring size array as well
+        discard_after_arg = 2;
+      }
     }
     specialized_geofunc += suffix(arg_ti.get_type());
     if (arg_ti.get_subtype() == kGEOGRAPHY && arg_ti.get_output_srid() == 4326) {
+      if (arg_ti.get_type() == kMULTILINESTRING) {
+        throw QueryNotSupported(rex_function->getName() +
+                                " Geodesic is not supported for MULTILINESTRING");
+      }
       specialized_geofunc += "_Geodesic"s;
     }
   }
 
+  geoargs.erase(geoargs.begin() + discard_after_arg, geoargs.end());
+
   // Add input compression mode and SRID args to enable on-the-fly
   // decompression/transforms
   Datum input_compression;

Tests/GeospatialTest.cpp

@@ -1673,6 +1673,13 @@ TEST(GeoSpatial, Math) {
             R"(SELECT ST_Length(CAST (ST_GeomFromText('LINESTRING(-76.6168198439371 39.9703199555959, -80.5189990254673 40.6493554919257, -82.5189990254673 42.6493554919257)', 4326) as GEOGRAPHY));)",
             dt)),
         static_cast<double>(0.01));
+    // Cartesian length of a planar multi path
+    ASSERT_NEAR(
+        static_cast<double>(6.65685),
+        v<double>(run_simple_agg(
+            R"(SELECT ST_Length('MULTILINESTRING((1 0, 0 1, -1 0, 0 -1, 1 0),(2 2,2 3))');)",
+            dt)),
+        static_cast<double>(0.0001));
 
     // ST_Perimeter
     // Cartesian perimeter of a planar polygon