-<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.19 2007/09/21 21:25:42 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.20 2007/09/30 19:54:57 tgl Exp $ -->
<chapter id="storage">
byte) in bytes. As a special case, if the remaining bits are all zero
(which would be impossible for a self-inclusive length), the value is a
pointer to out-of-line data stored in a separate TOAST table. (The size of
-a TOAST pointer is known a priori, so it doesn't need to be represented in
-the header.) Values with single-byte headers aren't aligned on any particular
+a TOAST pointer is given in the second byte of the datum.)
+Values with single-byte headers aren't aligned on any particular
boundary, either. Lastly, when the highest-order or lowest-order bit is
clear but the adjacent bit is set, the content of the datum has been
compressed and must be decompressed before use. In this case the remaining
<acronym>TOAST</> table in which to look and the OID of the specific value
(its <structfield>chunk_id</>). For convenience, pointer datums also store the
logical datum size (original uncompressed data length) and actual stored size
-(different if compression was applied). Allowing for the varlena header byte,
-the total size of a <acronym>TOAST</> pointer datum is therefore 17 bytes
+(different if compression was applied). Allowing for the varlena header bytes,
+the total size of a <acronym>TOAST</> pointer datum is therefore 18 bytes
regardless of the actual size of the represented value.
</para>
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.75 2007/09/26 23:29:10 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.76 2007/09/30 19:54:58 tgl Exp $
*
*
* INTERFACE ROUTINES
#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \
((toast_pointer).va_extsize < (toast_pointer).va_rawsize - VARHDRSZ)
+/*
+ * Macro to fetch the possibly-unaligned contents of an EXTERNAL datum
+ * into a local "struct varatt_external" toast pointer. This should be
+ * just a memcpy, but some versions of gcc seem to produce broken code
+ * that assumes the datum contents are aligned. Introducing an explicit
+ * intermediate "varattrib_1b_e *" variable seems to fix it.
+ */
+#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \
+do { \
+ varattrib_1b_e *attre = (varattrib_1b_e *) (attr); \
+ Assert(VARSIZE_ANY_EXHDR(attre) == sizeof(toast_pointer)); \
+ memcpy(&(toast_pointer), VARDATA_EXTERNAL(attre), sizeof(toast_pointer)); \
+} while (0)
+
+
static void toast_delete_datum(Relation rel, Datum value);
static Datum toast_save_datum(Relation rel, Datum value,
bool use_wal, bool use_fsm);
{
struct varatt_external toast_pointer;
- memcpy(&toast_pointer, VARDATA_SHORT(attr), sizeof(toast_pointer));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/* fast path for non-compressed external datums */
if (!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
/* va_rawsize is the size of the original datum -- including header */
struct varatt_external toast_pointer;
- memcpy(&toast_pointer, VARDATA_SHORT(attr), sizeof(toast_pointer));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
result = toast_pointer.va_rawsize;
}
else if (VARATT_IS_COMPRESSED(attr))
*/
struct varatt_external toast_pointer;
- memcpy(&toast_pointer, VARDATA_SHORT(attr), sizeof(toast_pointer));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
result = toast_pointer.va_extsize;
}
else if (VARATT_IS_SHORT(attr))
VARATT_IS_EXTERNAL(old_value))
{
if (toast_isnull[i] || !VARATT_IS_EXTERNAL(new_value) ||
- memcmp(VARDATA_SHORT(old_value),
- VARDATA_SHORT(new_value),
- sizeof(struct varatt_external)) != 0)
+ memcmp((char *) old_value, (char *) new_value,
+ VARSIZE_EXTERNAL(old_value)) != 0)
{
/*
* The old external stored value isn't needed any more
Datum t_values[3];
bool t_isnull[3];
CommandId mycid = GetCurrentCommandId();
- struct varlena *result;
+ varattrib_pointer *result;
struct varatt_external toast_pointer;
struct
{
/*
* Create the TOAST pointer value that we'll return
*/
- result = (struct varlena *) palloc(sizeof(varattrib_pointer));
- SET_VARSIZE_EXTERNAL(result);
- memcpy(VARDATA_SHORT(result), &toast_pointer, sizeof(toast_pointer));
+ result = (varattrib_pointer *) palloc(sizeof(varattrib_pointer));
+ SET_VARSIZE_EXTERNAL(result, sizeof(varattrib_pointer));
+ memcpy(VARDATA_EXTERNAL(result), &toast_pointer, sizeof(toast_pointer));
return PointerGetDatum(result);
}
return;
/* Must copy to access aligned fields */
- memcpy(&toast_pointer, VARDATA_SHORT(attr),
- sizeof(struct varatt_external));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/*
* Open the toast relation and its index
int32 chunksize;
/* Must copy to access aligned fields */
- memcpy(&toast_pointer, VARDATA_SHORT(attr),
- sizeof(struct varatt_external));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
ressize = toast_pointer.va_extsize;
numchunks = ((ressize - 1) / TOAST_MAX_CHUNK_SIZE) + 1;
Assert(VARATT_IS_EXTERNAL(attr));
/* Must copy to access aligned fields */
- memcpy(&toast_pointer, VARDATA_SHORT(attr),
- sizeof(struct varatt_external));
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
/*
* It's nonsense to fetch slices of a compressed datum -- this isn't lo_*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.429 2007/09/25 22:21:55 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.430 2007/09/30 19:54:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 200709251
+#define CATALOG_VERSION_NO 200709301
#endif
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1995, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/postgres.h,v 1.83 2007/09/27 21:01:59 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/postgres.h,v 1.84 2007/09/30 19:54:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
typedef struct
{
uint8 va_header;
- char va_data[1]; /* Data or TOAST pointer */
+ char va_data[1]; /* Data begins here */
} varattrib_1b;
typedef struct
{
- uint8 va_header;
+ uint8 va_header; /* Always 0x80 or 0x01 */
+ uint8 va_len_1be; /* Physical length of datum */
+ char va_data[1]; /* Data (for now always a TOAST pointer) */
+} varattrib_1b_e;
+
+typedef struct
+{
+ uint8 va_header; /* Always 0x80 or 0x01 */
+ uint8 va_len_1be; /* Physical length of datum */
char va_data[sizeof(struct varatt_external)];
} varattrib_pointer;
(((varattrib_4b *) (PTR))->va_4byte.va_header & 0x3FFFFFFF)
#define VARSIZE_1B(PTR) \
(((varattrib_1b *) (PTR))->va_header & 0x7F)
-/* Currently there is only one size of toast pointer, but someday maybe not */
#define VARSIZE_1B_E(PTR) \
- (sizeof(varattrib_pointer))
+ (((varattrib_1b_e *) (PTR))->va_len_1be)
#define SET_VARSIZE_4B(PTR,len) \
(((varattrib_4b *) (PTR))->va_4byte.va_header = (len) & 0x3FFFFFFF)
(((varattrib_4b *) (PTR))->va_4byte.va_header = ((len) & 0x3FFFFFFF) | 0x40000000)
#define SET_VARSIZE_1B(PTR,len) \
(((varattrib_1b *) (PTR))->va_header = (len) | 0x80)
-#define SET_VARSIZE_1B_E(PTR) \
- (((varattrib_1b *) (PTR))->va_header = 0x80)
+#define SET_VARSIZE_1B_E(PTR,len) \
+ (((varattrib_1b_e *) (PTR))->va_header = 0x80, \
+ ((varattrib_1b_e *) (PTR))->va_len_1be = (len))
#else /* !WORDS_BIGENDIAN */
((((varattrib_4b *) (PTR))->va_4byte.va_header >> 2) & 0x3FFFFFFF)
#define VARSIZE_1B(PTR) \
((((varattrib_1b *) (PTR))->va_header >> 1) & 0x7F)
-/* Currently there is only one size of toast pointer, but someday maybe not */
#define VARSIZE_1B_E(PTR) \
- (sizeof(varattrib_pointer))
+ (((varattrib_1b_e *) (PTR))->va_len_1be)
#define SET_VARSIZE_4B(PTR,len) \
(((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2))
(((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2) | 0x02)
#define SET_VARSIZE_1B(PTR,len) \
(((varattrib_1b *) (PTR))->va_header = (((uint8) (len)) << 1) | 0x01)
-#define SET_VARSIZE_1B_E(PTR) \
- (((varattrib_1b *) (PTR))->va_header = 0x01)
+#define SET_VARSIZE_1B_E(PTR,len) \
+ (((varattrib_1b_e *) (PTR))->va_header = 0x01, \
+ ((varattrib_1b_e *) (PTR))->va_len_1be = (len))
#endif /* WORDS_BIGENDIAN */
#define VARDATA_4B(PTR) (((varattrib_4b *) (PTR))->va_4byte.va_data)
#define VARDATA_4B_C(PTR) (((varattrib_4b *) (PTR))->va_compressed.va_data)
#define VARDATA_1B(PTR) (((varattrib_1b *) (PTR))->va_data)
+#define VARDATA_1B_E(PTR) (((varattrib_1b_e *) (PTR))->va_data)
#define VARRAWSIZE_4B_C(PTR) \
(((varattrib_4b *) (PTR))->va_compressed.va_rawsize)
#define VARDATA_SHORT(PTR) VARDATA_1B(PTR)
#define VARSIZE_EXTERNAL(PTR) VARSIZE_1B_E(PTR)
+#define VARDATA_EXTERNAL(PTR) VARDATA_1B_E(PTR)
#define VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR)
#define VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR)
#define SET_VARSIZE(PTR, len) SET_VARSIZE_4B(PTR, len)
#define SET_VARSIZE_SHORT(PTR, len) SET_VARSIZE_1B(PTR, len)
#define SET_VARSIZE_COMPRESSED(PTR, len) SET_VARSIZE_4B_C(PTR, len)
-#define SET_VARSIZE_EXTERNAL(PTR) SET_VARSIZE_1B_E(PTR)
+#define SET_VARSIZE_EXTERNAL(PTR, len) SET_VARSIZE_1B_E(PTR, len)
#define VARSIZE_ANY(PTR) \
(VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR) : \
VARSIZE_4B(PTR)))
#define VARSIZE_ANY_EXHDR(PTR) \
- (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR)-1 : \
+ (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR)-2 : \
(VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR)-1 : \
VARSIZE_4B(PTR)-4))
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