Gpexpand use gp_add_segment to register primaries.

Currently, dbid is used in tablespace path. Hence, while creating
segment need dbid. To get the dbid need to add segment to catalog
first. But adding segment to catalog before creating causes
issues. Hence, modify gpexpand to not let database generate the dbid,
but instead pass the dbid upfront generated while registering in
catalog. This way dbid used while creating the segment will be same as
dbid in catalog.
Reviewed-by: NJimmy Yih <jyih@pivotal.io>

gpMgmt/bin/gppylib/system/configurationImplGpdb.py

@@ -126,10 +126,8 @@ class GpConfigurationProviderUsingGpdbCatalog(GpConfigurationProvider) :
         for seg in update.mirror_to_add:
             mirror_map[ seg.getSegmentContentId() ] = seg
 
-        # reset dbId of new primary and mirror segments to -1
+        # reset dbId of new mirror segments to -1
         # before invoking the operations which will assign them new ids
-        for seg in update.primary_to_add:
-            seg.setSegmentDbId(-1)
         for seg in update.mirror_to_add:
             seg.setSegmentDbId(-1)
 
@@ -273,16 +271,22 @@ class GpConfigurationProviderUsingGpdbCatalog(GpConfigurationProvider) :
 
     def __callSegmentAdd(self, conn, gpArray, seg):
         """
-        Call gp_add_segment_primary() to add the primary.
-        Return the new segment's dbid.
+        Ideally, should call gp_add_segment_primary() to add the
+        primary. But due to chicken-egg problem, need dbid for
+        creating the segment but can't add to catalog before creating
+        segment. Hence, instead using gp_add_segment() which takes
+        dbid and registers in catalog using the same.  Return the new
+        segment's dbid.
         """
         logger.debug('callSegmentAdd %s' % repr(seg))
 
-        sql = "SELECT gp_add_segment_primary(%s, %s, %s, %s)" \
+        sql = "SELECT gp_add_segment(%s::int2, %s::int2, 'p', 'p', 'n', 'u', %s, %s, %s, %s)" \
             % (
+                self.__toSqlIntValue(seg.getSegmentDbId()),
+                self.__toSqlIntValue(seg.getSegmentContentId()),
+                self.__toSqlIntValue(seg.getSegmentPort()),
                 self.__toSqlTextValue(seg.getSegmentHostName()),
                 self.__toSqlTextValue(seg.getSegmentAddress()),
-                self.__toSqlIntValue(seg.getSegmentPort()),
                 self.__toSqlTextValue(seg.getSegmentDataDirectory()),
               )
         logger.debug(sql)