diff options
Diffstat (limited to 'src/include/storage/itemptr.h')
| -rw-r--r-- | src/include/storage/itemptr.h | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/src/include/storage/itemptr.h b/src/include/storage/itemptr.h index 626c98f9691..d87101f2701 100644 --- a/src/include/storage/itemptr.h +++ b/src/include/storage/itemptr.h @@ -49,6 +49,28 @@ ItemPointerData; typedef ItemPointerData *ItemPointer; /* ---------------- + * special values used in heap tuples (t_ctid) + * ---------------- + */ + +/* + * If a heap tuple holds a speculative insertion token rather than a real + * TID, ip_posid is set to SpecTokenOffsetNumber, and the token is stored in + * ip_blkid. SpecTokenOffsetNumber must be higher than MaxOffsetNumber, so + * that it can be distinguished from a valid offset number in a regular item + * pointer. + */ +#define SpecTokenOffsetNumber 0xfffe + +/* + * When a tuple is moved to a different partition by UPDATE, the t_ctid of + * the old tuple version is set to this magic value. + */ +#define MovedPartitionsOffsetNumber 0xfffd +#define MovedPartitionsBlockNumber InvalidBlockNumber + + +/* ---------------- * support macros * ---------------- */ @@ -160,7 +182,10 @@ typedef ItemPointerData *ItemPointer; * partition. */ #define ItemPointerIndicatesMovedPartitions(pointer) \ - !BlockNumberIsValid(ItemPointerGetBlockNumberNoCheck(pointer)) +( \ + ItemPointerGetOffsetNumber(pointer) == MovedPartitionsOffsetNumber && \ + ItemPointerGetBlockNumberNoCheck(pointer) == MovedPartitionsBlockNumber \ +) /* * ItemPointerSetMovedPartitions @@ -168,7 +193,7 @@ typedef ItemPointerData *ItemPointer; * different partition. */ #define ItemPointerSetMovedPartitions(pointer) \ - ItemPointerSetBlockNumber((pointer), InvalidBlockNumber) + ItemPointerSet((pointer), MovedPartitionsBlockNumber, MovedPartitionsOffsetNumber) /* ---------------- * externs |