diff options
Diffstat (limited to 'src/include/nodes/relation.h')
| -rw-r--r-- | src/include/nodes/relation.h | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index 1c864f2e721..45d53be5f62 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: relation.h,v 1.49 2000/09/29 18:21:39 tgl Exp $ + * $Id: relation.h,v 1.50 2000/11/12 00:37:01 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -82,6 +82,14 @@ typedef enum CostSelector * upon creation of the RelOptInfo object; they are filled in when * set_base_rel_pathlist processes the object. * + * Note: if a base relation is the root of an inheritance tree + * (SELECT FROM foo*) it is still considered a base rel. We will + * generate a list of candidate Paths for accessing that table itself, + * and also generate baserel RelOptInfo nodes for each child table, + * with their own candidate Path lists. Then, an AppendPath is built + * from the cheapest Path for each of these tables, and set to be the + * only available Path for the inheritance baserel. + * * * The presence of the remaining fields depends on the restrictions * and joins that the relation participates in: * @@ -313,6 +321,9 @@ typedef struct IndexPath double rows; /* estimated number of result tuples */ } IndexPath; +/* + * TidPath represents a scan by TID + */ typedef struct TidPath { Path path; @@ -321,6 +332,17 @@ typedef struct TidPath } TidPath; /* + * AppendPath represents an Append plan, ie, successive execution of + * several member plans. Currently it is only used to handle expansion + * of inheritance trees. + */ +typedef struct AppendPath +{ + Path path; + List *subpaths; /* list of component Paths */ +} AppendPath; + +/* * All join-type paths share these fields. */ |