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/*-------------------------------------------------------------------------
*
* toast_internals.h
* Internal definitions for the TOAST system.
*
* Copyright (c) 2000-2021, PostgreSQL Global Development Group
*
* src/include/access/toast_internals.h
*
*-------------------------------------------------------------------------
*/
#ifndef TOAST_INTERNALS_H
#define TOAST_INTERNALS_H
#include "access/toast_compression.h"
#include "storage/lockdefs.h"
#include "utils/relcache.h"
#include "utils/snapshot.h"
/*
* The information at the start of the compressed toast data.
*/
typedef struct toast_compress_header
{
int32 vl_len_; /* varlena header (do not touch directly!) */
uint32 tcinfo; /* 2 bits for compression method and 30 bits
* external size; see va_extinfo */
} toast_compress_header;
/*
* Utilities for manipulation of header information for compressed
* toast entries.
*/
#define TOAST_COMPRESS_EXTSIZE(ptr) \
(((toast_compress_header *) (ptr))->tcinfo & VARLENA_EXTSIZE_MASK)
#define TOAST_COMPRESS_METHOD(ptr) \
(((toast_compress_header *) (ptr))->tcinfo >> VARLENA_EXTSIZE_BITS)
#define TOAST_COMPRESS_SET_SIZE_AND_COMPRESS_METHOD(ptr, len, cm_method) \
do { \
Assert((len) > 0 && (len) <= VARLENA_EXTSIZE_MASK); \
Assert((cm_method) == TOAST_PGLZ_COMPRESSION_ID || \
(cm_method) == TOAST_LZ4_COMPRESSION_ID); \
((toast_compress_header *) (ptr))->tcinfo = \
(len) | ((uint32) (cm_method) << VARLENA_EXTSIZE_BITS); \
} while (0)
extern Datum toast_compress_datum(Datum value, char cmethod);
extern Oid toast_get_valid_index(Oid toastoid, LOCKMODE lock);
extern void toast_delete_datum(Relation rel, Datum value, bool is_speculative);
extern Datum toast_save_datum(Relation rel, Datum value,
struct varlena *oldexternal, int options);
extern int toast_open_indexes(Relation toastrel,
LOCKMODE lock,
Relation **toastidxs,
int *num_indexes);
extern void toast_close_indexes(Relation *toastidxs, int num_indexes,
LOCKMODE lock);
extern void init_toast_snapshot(Snapshot toast_snapshot);
#endif /* TOAST_INTERNALS_H */
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