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Support for INCLUDE attributes in GiST indexes

Similarly to B-tree, GiST index access method gets support of INCLUDE
attributes.  These attributes aren't used for tree navigation and aren't
present in non-leaf pages.  But they are present in leaf pages and can be
fetched during index-only scan.

The point of having INCLUDE attributes in GiST indexes is slightly different
from the point of having them in B-tree.  The main point of INCLUDE attributes
in B-tree is to define UNIQUE constraint over part of attributes enabled for
index-only scan.  In GiST the main point of INCLUDE attributes is to use
index-only scan for attributes, whose data types don't have GiST opclasses.

Discussion: https://postgr.es/m/73A1A452-AD5F-40D4-BD61-978622FF75C1%40yandex-team.ru
Author: Andrey Borodin, with small changes by me
Reviewed-by: Andreas Karlsson
This commit is contained in:
Alexander Korotkov
2019-03-10 11:36:47 +03:00
parent a0b7626268
commit f2e403803f
16 changed files with 382 additions and 48 deletions

View File

@@ -78,7 +78,9 @@ typedef struct GISTSTATE
MemoryContext scanCxt; /* context for scan-lifespan data */
MemoryContext tempCxt; /* short-term context for calling functions */
TupleDesc tupdesc; /* index's tuple descriptor */
TupleDesc leafTupdesc; /* index's tuple descriptor */
TupleDesc nonLeafTupdesc; /* truncated tuple descriptor for non-leaf
* pages */
TupleDesc fetchTupdesc; /* tuple descriptor for tuples returned in an
* index-only scan */