diff options
Diffstat (limited to 'src/include/nodes/relation.h')
| -rw-r--r-- | src/include/nodes/relation.h | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index 4698e4d8cb..2e4e1834fe 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.104 2005/03/27 06:29:45 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.105 2005/04/19 22:35:17 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -342,6 +342,9 @@ typedef struct Path * tuples matched during any scan. (The executor is smart enough not to return * the same tuple more than once, even if it is matched in multiple scans.) * + * XXX bitmap index scans will probably obviate the need for plain OR + * indexscans, allowing a lot of this to be simplified. + * * 'indexinfo' is a list of IndexOptInfo nodes, one per scan to be performed. * * 'indexclauses' is a list of index qualifications, also one per scan. @@ -390,6 +393,30 @@ typedef struct IndexPath } IndexPath; /* + * BitmapHeapPath represents one or more indexscans that generate TID bitmaps + * instead of directly accessing the heap, followed by AND/OR combinations + * to produce a single bitmap, followed by a heap scan that uses the bitmap. + * Note that the output is always considered unordered, since it will come + * out in physical heap order no matter what the underlying indexes did. + * + * The individual indexscans are represented by IndexPath nodes, and any + * logic on top of them is represented by regular AND and OR expressions. + * Notice that we can use the same IndexPath node both to represent an + * ordered index scan, and as the child of a BitmapHeapPath that represents + * scanning the same index in an unordered way. + * + * BitmapHeapPaths can be nestloop inner indexscans. The isjoininner and + * rows fields serve the same purpose as for plain IndexPaths. + */ +typedef struct BitmapHeapPath +{ + Path path; + Node *bitmapqual; /* the IndexPath/AND/OR tree */ + bool isjoininner; /* T if it's a nestloop inner scan */ + double rows; /* estimated number of result tuples */ +} BitmapHeapPath; + +/* * TidPath represents a scan by TID * * tideval is an implicitly OR'ed list of quals of the form CTID = something. |