diff options
| author | Tom Lane | 2007-09-30 19:54:58 +0000 |
|---|---|---|
| committer | Tom Lane | 2007-09-30 19:54:58 +0000 |
| commit | 10f50fe4d9fa8fa421cb1dfaa33f929666fe7680 (patch) | |
| tree | bd5f369cf205d6384eba25844820826354d8faf0 /src/include/postgres.h | |
| parent | da2bda0d1aa9d2b1b01282a4ec165c98e62b7839 (diff) | |
Add an extra header byte to TOAST-pointer datums to represent their size
explicitly. This means a TOAST pointer takes 18 bytes instead of 17 --- still
smaller than in 8.2 --- which seems a good tradeoff to ensure we won't have
painted ourselves into a corner if we want to support multiple types of TOAST
pointer later on. Per discussion with Greg Stark.
Diffstat (limited to 'src/include/postgres.h')
| -rw-r--r-- | src/include/postgres.h | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/src/include/postgres.h b/src/include/postgres.h index 5b5cdcba23..786dc3e5e8 100644 --- a/src/include/postgres.h +++ b/src/include/postgres.h @@ -100,12 +100,20 @@ typedef union 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; @@ -161,9 +169,8 @@ typedef struct (((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) @@ -171,8 +178,9 @@ typedef struct (((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 */ @@ -194,9 +202,8 @@ typedef struct ((((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)) @@ -204,8 +211,9 @@ typedef struct (((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 */ @@ -220,6 +228,7 @@ typedef struct #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) @@ -249,6 +258,7 @@ typedef struct #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) @@ -258,7 +268,7 @@ typedef struct #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) : \ @@ -266,7 +276,7 @@ typedef struct 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)) |