DBZ-1144 Do not translate geometry point (PostGIS) to PG point

This code was effectivelly dead. It was used only when PostGIS geometry type was created inside the public schema and was responsible for translating of PostGIS point to PG point. When we introduced the full support for PostGIS types in Debezium the code was no longer used as PostGIS types are typically created in separate schema.
So now we support

* POINT type (postgres point)
* postgis GEOMETRY in arbitrary schema (including geometry point)

Author: jpechane

src/decoderbufs.c

@@ -60,12 +60,6 @@
 #error Expecting timestamps to be represented as integers, not as floating-point.
 #endif
 
-#ifdef USE_POSTGIS
-/* POSTGIS version define so it doesn't redef macros */
-#define POSTGIS_PGSQL_VERSION 94
-#include "liblwgeom.h"
-#endif
-
 PG_MODULE_MAGIC;
 
 /* define a time macro to convert TimestampTz into something more sane,
@@ -80,10 +74,6 @@ typedef struct {
   bool debug_mode;
 } DecoderData;
 
-/* GLOBALs for PostGIS dynamic OIDs */
-Oid geometry_oid = InvalidOid;
-Oid geography_oid = InvalidOid;
-
 /* these must be available to pg_dlsym() */
 extern void _PG_init(void);
 extern void _PG_output_plugin_init(OutputPluginCallbacks *cb);
@@ -177,22 +167,6 @@ static void pg_decode_shutdown(LogicalDecodingContext *ctx) {
 /* BEGIN callback */
 static void pg_decode_begin_txn(LogicalDecodingContext *ctx,
                                 ReorderBufferTXN *txn) {
-#ifdef USE_POSTGIS
-  // set PostGIS geometry type id (these are dynamic)
-  // TODO: Figure out how to make sure we get the typid's from postgis extension namespace
-  if (geometry_oid == InvalidOid) {
-    geometry_oid = TypenameGetTypid("geometry");
-    if (geometry_oid != InvalidOid) {
-      elog(DEBUG1, "PostGIS geometry type detected: %u", geometry_oid);
-    }
-  }
-  if (geography_oid == InvalidOid) {
-    geography_oid = TypenameGetTypid("geography");
-    if (geography_oid != InvalidOid) {
-      elog(DEBUG1, "PostGIS geometry type detected: %u", geography_oid);
-    }
-  }
-#endif
 }
 
 /* COMMIT callback */
@@ -280,42 +254,6 @@ static void print_row_msg(StringInfo out, Decoderbufs__RowMessage *rmsg) {
 
 }
 
-static bool geography_point_as_decoderbufs_point(Datum datum,
-                                                 Decoderbufs__Point *p) {
-#ifdef USE_POSTGIS
-  GSERIALIZED *geom;
-  LWGEOM *lwgeom;
-  LWPOINT *point = NULL;
-  POINT2D p2d;
-
-  geom = (GSERIALIZED *)PG_DETOAST_DATUM(datum);
-  if (gserialized_get_type(geom) != POINTTYPE) {
-    return false;
-  }
-
-  lwgeom = lwgeom_from_gserialized(geom);
-  point = lwgeom_as_lwpoint(lwgeom);
-  if (lwgeom_is_empty(lwgeom)) {
-    return false;
-  }
-
-  getPoint2d_p(point->point, 0, &p2d);
-
-  if (p != NULL) {
-    Decoderbufs__Point dp = DECODERBUFS__POINT__INIT;
-    dp.x = p2d.x;
-    dp.y = p2d.y;
-    memcpy(p, &dp, sizeof(dp));
-    elog(DEBUG1, "Translating geography to point: (x,y) = (%f,%f)", p->x, p->y);
-  }
-
-  return true;
-#else
-  elog(DEBUG1, "PostGIS support is off, recompile decoderbufs with USE_POSTGIS option!");
-  return false;
-#endif
-}
-
 /* set a datum value based on its OID specified by typid */
 static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
                             Oid typoutput, Datum datum) {
@@ -435,13 +373,7 @@ static void set_datum_value(Decoderbufs__DatumMessage *datum_msg, Oid typid,
       datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT;
       break;
     default:
-      // PostGIS uses dynamic OIDs so we need to check the type again here
-      if (typid == geometry_oid || typid == geography_oid) {
-        elog(DEBUG1, "Converting geography point to datum_point");
-        datum_msg->datum_point = palloc(sizeof(Decoderbufs__Point));
-        geography_point_as_decoderbufs_point(datum, datum_msg->datum_point);
-        datum_msg->datum_case = DECODERBUFS__DATUM_MESSAGE__DATUM_DATUM_POINT;
-      } else {
+      {
         int len;
         elog(DEBUG1, "Encountered unknown typid: %d, using bytes", typid);
         output = OidOutputFunctionCall(typoutput, datum);