diff options
Diffstat (limited to 'src/include/postgres.h')
| -rw-r--r-- | src/include/postgres.h | 106 |
1 files changed, 54 insertions, 52 deletions
diff --git a/src/include/postgres.h b/src/include/postgres.h index 2ccbea8e502..8e02f911086 100644 --- a/src/include/postgres.h +++ b/src/include/postgres.h @@ -55,8 +55,8 @@ /* * struct varatt_external is a traditional "TOAST pointer", that is, the * information needed to fetch a Datum stored out-of-line in a TOAST table. - * The data is compressed if and only if the size stored in va_extinfo < - * va_rawsize - VARHDRSZ. + * The data is compressed if and only if the external size stored in + * va_extinfo is less than va_rawsize - VARHDRSZ. * * This struct must not contain any padding, because we sometimes compare * these pointers using memcmp. @@ -76,6 +76,13 @@ typedef struct varatt_external } varatt_external; /* + * These macros define the "saved size" portion of va_extinfo. Its remaining + * two high-order bits identify the compression method. + */ +#define VARLENA_EXTSIZE_BITS 30 +#define VARLENA_EXTSIZE_MASK ((1U << VARLENA_EXTSIZE_BITS) - 1) + +/* * struct varatt_indirect is a "TOAST pointer" representing an out-of-line * Datum that's stored in memory, not in an external toast relation. * The creator of such a Datum is entirely responsible that the referenced @@ -149,7 +156,7 @@ typedef union { uint32 va_header; uint32 va_tcinfo; /* Original data size (excludes header) and - * compression method */ + * compression method; see va_extinfo */ char va_data[FLEXIBLE_ARRAY_MEMBER]; /* Compressed data */ } va_compressed; } varattrib_4b; @@ -235,6 +242,7 @@ typedef struct #define SET_VARTAG_1B_E(PTR,tag) \ (((varattrib_1b_e *) (PTR))->va_header = 0x80, \ ((varattrib_1b_e *) (PTR))->va_tag = (tag)) + #else /* !WORDS_BIGENDIAN */ #define VARATT_IS_4B(PTR) \ @@ -267,36 +275,28 @@ typedef struct #define SET_VARTAG_1B_E(PTR,tag) \ (((varattrib_1b_e *) (PTR))->va_header = 0x01, \ ((varattrib_1b_e *) (PTR))->va_tag = (tag)) -#endif /* WORDS_BIGENDIAN */ -#define VARHDRSZ_SHORT offsetof(varattrib_1b, va_data) -#define VARATT_SHORT_MAX 0x7F -#define VARATT_CAN_MAKE_SHORT(PTR) \ - (VARATT_IS_4B_U(PTR) && \ - (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX) -#define VARATT_CONVERTED_SHORT_SIZE(PTR) \ - (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) - -#define VARHDRSZ_EXTERNAL offsetof(varattrib_1b_e, va_data) -#define VARHDRSZ_COMPRESS offsetof(varattrib_4b, va_compressed.va_data) +#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 VARLENA_RAWSIZE_BITS 30 -#define VARLENA_RAWSIZE_MASK ((1U << VARLENA_RAWSIZE_BITS) - 1) - /* - * va_tcinfo in va_compress contains raw size of datum and compression method. + * Externally visible TOAST macros begin here. */ -#define VARRAWSIZE_4B_C(PTR) \ - (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo & VARLENA_RAWSIZE_MASK) -#define VARCOMPRESS_4B_C(PTR) \ - (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo >> VARLENA_RAWSIZE_BITS) -/* Externally visible macros */ +#define VARHDRSZ_EXTERNAL offsetof(varattrib_1b_e, va_data) +#define VARHDRSZ_COMPRESSED offsetof(varattrib_4b, va_compressed.va_data) +#define VARHDRSZ_SHORT offsetof(varattrib_1b, va_data) + +#define VARATT_SHORT_MAX 0x7F +#define VARATT_CAN_MAKE_SHORT(PTR) \ + (VARATT_IS_4B_U(PTR) && \ + (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX) +#define VARATT_CONVERTED_SHORT_SIZE(PTR) \ + (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) /* * In consumers oblivious to data alignment, call PG_DETOAST_DATUM_PACKED(), @@ -336,35 +336,6 @@ typedef struct (VARATT_IS_EXTERNAL(PTR) && VARTAG_IS_EXPANDED(VARTAG_EXTERNAL(PTR))) #define VARATT_IS_EXTERNAL_NON_EXPANDED(PTR) \ (VARATT_IS_EXTERNAL(PTR) && !VARTAG_IS_EXPANDED(VARTAG_EXTERNAL(PTR))) - -/* - * va_extinfo in varatt_external contains actual length of the external data - * and compression method if external data is compressed. - */ -#define VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) \ - ((toast_pointer).va_extinfo & VARLENA_RAWSIZE_MASK) - -#define VARATT_EXTERNAL_SET_SIZE_AND_COMPRESSION(toast_pointer, len, cm) \ - do { \ - Assert((cm) == TOAST_PGLZ_COMPRESSION_ID || \ - (cm) == TOAST_LZ4_COMPRESSION_ID); \ - ((toast_pointer).va_extinfo = (len) | (cm) << VARLENA_RAWSIZE_BITS); \ - } while (0) - -#define VARATT_EXTERNAL_GET_COMPRESSION(PTR) \ - ((toast_pointer).va_extinfo >> VARLENA_RAWSIZE_BITS) - -/* - * Testing whether an externally-stored value is compressed now requires - * comparing size stored in va_extinfo (the actual length of the external data) - * to rawsize (the original uncompressed datum's size). The latter includes - * VARHDRSZ overhead, the former doesn't. We never use compression unless it - * actually saves space, so we expect either equality or less-than. - */ -#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \ - (VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) < \ - (toast_pointer).va_rawsize - VARHDRSZ) - #define VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR) #define VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR)) @@ -390,6 +361,37 @@ typedef struct #define VARDATA_ANY(PTR) \ (VARATT_IS_1B(PTR) ? VARDATA_1B(PTR) : VARDATA_4B(PTR)) +/* Decompressed size and compression method of an external compressed Datum */ +#define VARDATA_COMPRESSED_GET_EXTSIZE(PTR) \ + (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo & VARLENA_EXTSIZE_MASK) +#define VARDATA_COMPRESSED_GET_COMPRESS_METHOD(PTR) \ + (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo >> VARLENA_EXTSIZE_BITS) + +/* Same, when working directly with a struct varatt_external */ +#define VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) \ + ((toast_pointer).va_extinfo & VARLENA_EXTSIZE_MASK) +#define VARATT_EXTERNAL_GET_COMPRESS_METHOD(toast_pointer) \ + ((toast_pointer).va_extinfo >> VARLENA_EXTSIZE_BITS) + +#define VARATT_EXTERNAL_SET_SIZE_AND_COMPRESS_METHOD(toast_pointer, len, cm) \ + do { \ + Assert((cm) == TOAST_PGLZ_COMPRESSION_ID || \ + (cm) == TOAST_LZ4_COMPRESSION_ID); \ + ((toast_pointer).va_extinfo = \ + (len) | ((uint32) (cm) << VARLENA_EXTSIZE_BITS)); \ + } while (0) + +/* + * Testing whether an externally-stored value is compressed now requires + * comparing size stored in va_extinfo (the actual length of the external data) + * to rawsize (the original uncompressed datum's size). The latter includes + * VARHDRSZ overhead, the former doesn't. We never use compression unless it + * actually saves space, so we expect either equality or less-than. + */ +#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \ + (VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) < \ + (toast_pointer).va_rawsize - VARHDRSZ) + /* ---------------------------------------------------------------- * Section 2: Datum type + support macros |