diff options
Diffstat (limited to 'src/include/access/genam.h')
| -rw-r--r-- | src/include/access/genam.h | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/src/include/access/genam.h b/src/include/access/genam.h index bf3fe96e26d..a8c0e029296 100644 --- a/src/include/access/genam.h +++ b/src/include/access/genam.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.78 2009/06/11 14:49:08 momjian Exp $ + * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.79 2009/07/29 20:56:19 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -85,6 +85,34 @@ typedef bool (*IndexBulkDeleteCallback) (ItemPointer itemptr, void *state); typedef struct IndexScanDescData *IndexScanDesc; typedef struct SysScanDescData *SysScanDesc; +/* + * Enumeration specifying the type of uniqueness check to perform in + * index_insert(). + * + * UNIQUE_CHECK_YES is the traditional Postgres immediate check, possibly + * blocking to see if a conflicting transaction commits. + * + * For deferrable unique constraints, UNIQUE_CHECK_PARTIAL is specified at + * insertion time. The index AM should test if the tuple is unique, but + * should not throw error, block, or prevent the insertion if the tuple + * appears not to be unique. We'll recheck later when it is time for the + * constraint to be enforced. The AM must return true if the tuple is + * known unique, false if it is possibly non-unique. In the "true" case + * it is safe to omit the later recheck. + * + * When it is time to recheck the deferred constraint, a pseudo-insertion + * call is made with UNIQUE_CHECK_EXISTING. The tuple is already in the + * index in this case, so it should not be inserted again. Rather, just + * check for conflicting live tuples (possibly blocking). + */ +typedef enum IndexUniqueCheck +{ + UNIQUE_CHECK_NO, /* Don't do any uniqueness checking */ + UNIQUE_CHECK_YES, /* Enforce uniqueness at insertion time */ + UNIQUE_CHECK_PARTIAL, /* Test uniqueness, but no error */ + UNIQUE_CHECK_EXISTING /* Check if existing tuple is unique */ +} IndexUniqueCheck; + /* * generalized index_ interface routines (in indexam.c) @@ -103,7 +131,7 @@ extern bool index_insert(Relation indexRelation, Datum *values, bool *isnull, ItemPointer heap_t_ctid, Relation heapRelation, - bool check_uniqueness); + IndexUniqueCheck checkUnique); extern IndexScanDesc index_beginscan(Relation heapRelation, Relation indexRelation, |