diff options
Diffstat (limited to 'src/include/access/htup.h')
| -rw-r--r-- | src/include/access/htup.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/src/include/access/htup.h b/src/include/access/htup.h index ce7b4a2d874..76306b67bb6 100644 --- a/src/include/access/htup.h +++ b/src/include/access/htup.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: htup.h,v 1.45 2001/01/24 19:43:19 momjian Exp $ + * $Id: htup.h,v 1.46 2001/02/21 19:07:04 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -32,7 +32,9 @@ #define MaxHeapAttributeNumber 1600 /* 8 * 200 */ /* - * to avoid wasting space, the attributes should be layed out in such a + * This is the on-disk copy of the tuple. + * + * To avoid wasting space, the attributes should be layed out in such a * way to reduce structure padding. */ typedef struct HeapTupleHeaderData @@ -51,12 +53,12 @@ typedef struct HeapTupleHeaderData uint16 t_infomask; /* various infos */ - uint8 t_hoff; /* sizeof tuple header */ + uint8 t_hoff; /* sizeof() tuple header */ /* ^ - 31 bytes - ^ */ bits8 t_bits[MinHeapTupleBitmapSize / 8]; - /* bit map of domains */ + /* bit map of NULLs */ /* MORE DATA FOLLOWS AT END OF STRUCT */ } HeapTupleHeaderData; @@ -174,6 +176,8 @@ typedef struct xl_heap_clean #define FirstLowInvalidHeapAttributeNumber (-8) /* + * This is the in-memory copy of the tuple. + * * This new HeapTuple for version >= 6.5 and this is why it was changed: * * 1. t_len moved off on-disk tuple data - ItemIdData is used to get len; @@ -190,10 +194,10 @@ typedef struct xl_heap_clean typedef struct HeapTupleData { uint32 t_len; /* length of *t_data */ - ItemPointerData t_self; /* SelfItemPointer */ + ItemPointerData t_self; /* SelfItemPointer */ Oid t_tableOid; /* table the tuple came from */ - MemoryContext t_datamcxt; /* mcxt in which allocated */ - HeapTupleHeader t_data; /* -> tuple header and data */ + MemoryContext t_datamcxt; /* memory context of allocation */ + HeapTupleHeader t_data; /* -> tuple header and data */ } HeapTupleData; typedef HeapTupleData *HeapTuple; |