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Split tuptoaster.c into three separate files.
detoast.c/h contain functions required to detoast a datum, partially or completely, plus a few other utility functions for examining the size of toasted datums. toast_internals.c/h contain functions that are used internally to the TOAST subsystem but which (mostly) do not need to be accessed from outside. heaptoast.c/h contains code that is intrinsically specific to the heap AM, either because it operates on HeapTuples or is based on the layout of a heap page. detoast.c and toast_internals.c are placed in src/backend/access/common rather than src/backend/access/heap. At present, both files still have dependencies on the heap, but that will be improved in a future commit. Patch by me, reviewed and tested by Prabhat Sabu, Thomas Munro, Andres Freund, and Álvaro Herrera. Discussion: http://postgr.es/m/CA+TgmoZv-=2iWM4jcw5ZhJeL18HF96+W1yJeYrnGMYdkFFnEpQ@mail.gmail.com
This commit is contained in:
Robert Haas
92
src/include/access/detoast.h
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92
src/include/access/detoast.h
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@@ -0,0 +1,92 @@
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/*-------------------------------------------------------------------------
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*
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* detoast.h
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* Access to compressed and external varlena values.
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*
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* Copyright (c) 2000-2019, PostgreSQL Global Development Group
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*
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* src/include/access/detoast.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef DETOAST_H
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#define DETOAST_H
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/*
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* Testing whether an externally-stored value is compressed now requires
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* comparing extsize (the actual length of the external data) to rawsize
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* (the original uncompressed datum's size). The latter includes VARHDRSZ
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* overhead, the former doesn't. We never use compression unless it actually
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* saves space, so we expect either equality or less-than.
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*/
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#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \
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((toast_pointer).va_extsize < (toast_pointer).va_rawsize - VARHDRSZ)
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/*
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* Macro to fetch the possibly-unaligned contents of an EXTERNAL datum
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* into a local "struct varatt_external" toast pointer. This should be
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* just a memcpy, but some versions of gcc seem to produce broken code
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* that assumes the datum contents are aligned. Introducing an explicit
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* intermediate "varattrib_1b_e *" variable seems to fix it.
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*/
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#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \
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do { \
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varattrib_1b_e *attre = (varattrib_1b_e *) (attr); \
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Assert(VARATT_IS_EXTERNAL(attre)); \
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Assert(VARSIZE_EXTERNAL(attre) == sizeof(toast_pointer) + VARHDRSZ_EXTERNAL); \
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memcpy(&(toast_pointer), VARDATA_EXTERNAL(attre), sizeof(toast_pointer)); \
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} while (0)
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/* Size of an EXTERNAL datum that contains a standard TOAST pointer */
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#define TOAST_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_external))
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/* Size of an EXTERNAL datum that contains an indirection pointer */
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#define INDIRECT_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_indirect))
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/* ----------
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* heap_tuple_fetch_attr() -
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*
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* Fetches an external stored attribute from the toast
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* relation. Does NOT decompress it, if stored external
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* in compressed format.
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* ----------
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*/
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extern struct varlena *heap_tuple_fetch_attr(struct varlena *attr);
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/* ----------
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* heap_tuple_untoast_attr() -
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*
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* Fully detoasts one attribute, fetching and/or decompressing
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* it as needed.
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* ----------
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*/
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extern struct varlena *heap_tuple_untoast_attr(struct varlena *attr);
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/* ----------
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* heap_tuple_untoast_attr_slice() -
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*
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* Fetches only the specified portion of an attribute.
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* (Handles all cases for attribute storage)
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* ----------
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*/
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extern struct varlena *heap_tuple_untoast_attr_slice(struct varlena *attr,
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int32 sliceoffset,
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int32 slicelength);
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/* ----------
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* toast_raw_datum_size -
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*
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* Return the raw (detoasted) size of a varlena datum
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* ----------
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*/
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extern Size toast_raw_datum_size(Datum value);
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/* ----------
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* toast_datum_size -
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*
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* Return the storage size of a varlena datum
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* ----------
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*/
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extern Size toast_datum_size(Datum value);
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#endif /* DETOAST_H */
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@@ -1,29 +1,22 @@
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/*-------------------------------------------------------------------------
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*
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* tuptoaster.h
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* POSTGRES definitions for external and compressed storage
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* heaptoast.h
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* Heap-specific definitions for external and compressed storage
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* of variable size attributes.
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*
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* Copyright (c) 2000-2019, PostgreSQL Global Development Group
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*
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* src/include/access/tuptoaster.h
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* src/include/access/heaptoast.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef TUPTOASTER_H
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#define TUPTOASTER_H
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#ifndef HEAPTOAST_H
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#define HEAPTOAST_H
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#include "access/htup_details.h"
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#include "storage/lockdefs.h"
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#include "utils/relcache.h"
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/*
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* This enables de-toasting of index entries. Needed until VACUUM is
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* smart enough to rebuild indexes from scratch.
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*/
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#define TOAST_INDEX_HACK
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/*
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* Find the maximum size of a tuple if there are to be N tuples per page.
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*/
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@@ -95,37 +88,6 @@
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sizeof(int32) - \
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VARHDRSZ)
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/* Size of an EXTERNAL datum that contains a standard TOAST pointer */
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#define TOAST_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_external))
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/* Size of an EXTERNAL datum that contains an indirection pointer */
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#define INDIRECT_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_indirect))
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/*
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* Testing whether an externally-stored value is compressed now requires
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* comparing extsize (the actual length of the external data) to rawsize
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* (the original uncompressed datum's size). The latter includes VARHDRSZ
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* overhead, the former doesn't. We never use compression unless it actually
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* saves space, so we expect either equality or less-than.
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*/
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#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \
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((toast_pointer).va_extsize < (toast_pointer).va_rawsize - VARHDRSZ)
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/*
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* Macro to fetch the possibly-unaligned contents of an EXTERNAL datum
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* into a local "struct varatt_external" toast pointer. This should be
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* just a memcpy, but some versions of gcc seem to produce broken code
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* that assumes the datum contents are aligned. Introducing an explicit
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* intermediate "varattrib_1b_e *" variable seems to fix it.
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*/
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#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \
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do { \
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varattrib_1b_e *attre = (varattrib_1b_e *) (attr); \
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Assert(VARATT_IS_EXTERNAL(attre)); \
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Assert(VARSIZE_EXTERNAL(attre) == sizeof(toast_pointer) + VARHDRSZ_EXTERNAL); \
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memcpy(&(toast_pointer), VARDATA_EXTERNAL(attre), sizeof(toast_pointer)); \
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} while (0)
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/* ----------
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* toast_insert_or_update -
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*
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@@ -144,36 +106,6 @@ extern HeapTuple toast_insert_or_update(Relation rel,
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*/
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extern void toast_delete(Relation rel, HeapTuple oldtup, bool is_speculative);
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/* ----------
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* heap_tuple_fetch_attr() -
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*
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* Fetches an external stored attribute from the toast
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* relation. Does NOT decompress it, if stored external
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* in compressed format.
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* ----------
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*/
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extern struct varlena *heap_tuple_fetch_attr(struct varlena *attr);
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/* ----------
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* heap_tuple_untoast_attr() -
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*
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* Fully detoasts one attribute, fetching and/or decompressing
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* it as needed.
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* ----------
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*/
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extern struct varlena *heap_tuple_untoast_attr(struct varlena *attr);
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/* ----------
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* heap_tuple_untoast_attr_slice() -
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*
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* Fetches only the specified portion of an attribute.
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* (Handles all cases for attribute storage)
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* ----------
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*/
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extern struct varlena *heap_tuple_untoast_attr_slice(struct varlena *attr,
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int32 sliceoffset,
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int32 slicelength);
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/* ----------
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* toast_flatten_tuple -
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*
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@@ -204,36 +136,4 @@ extern HeapTuple toast_build_flattened_tuple(TupleDesc tupleDesc,
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Datum *values,
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bool *isnull);
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/* ----------
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* toast_compress_datum -
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*
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* Create a compressed version of a varlena datum, if possible
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* ----------
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*/
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extern Datum toast_compress_datum(Datum value);
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/* ----------
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* toast_raw_datum_size -
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*
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* Return the raw (detoasted) size of a varlena datum
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* ----------
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*/
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extern Size toast_raw_datum_size(Datum value);
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/* ----------
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* toast_datum_size -
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*
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* Return the storage size of a varlena datum
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* ----------
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*/
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extern Size toast_datum_size(Datum value);
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/* ----------
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* toast_get_valid_index -
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*
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* Return OID of valid index associated to a toast relation
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* ----------
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*/
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extern Oid toast_get_valid_index(Oid toastoid, LOCKMODE lock);
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#endif /* TUPTOASTER_H */
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#endif /* HEAPTOAST_H */
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54
src/include/access/toast_internals.h
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54
src/include/access/toast_internals.h
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@@ -0,0 +1,54 @@
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/*-------------------------------------------------------------------------
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*
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* toast_internals.h
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* Internal definitions for the TOAST system.
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*
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* Copyright (c) 2000-2019, PostgreSQL Global Development Group
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*
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* src/include/access/toast_internals.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef TOAST_INTERNALS_H
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#define TOAST_INTERNALS_H
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#include "storage/lockdefs.h"
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#include "utils/relcache.h"
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#include "utils/snapshot.h"
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/*
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* The information at the start of the compressed toast data.
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*/
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typedef struct toast_compress_header
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{
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int32 vl_len_; /* varlena header (do not touch directly!) */
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int32 rawsize;
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} toast_compress_header;
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/*
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* Utilities for manipulation of header information for compressed
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* toast entries.
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*/
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#define TOAST_COMPRESS_HDRSZ ((int32) sizeof(toast_compress_header))
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#define TOAST_COMPRESS_RAWSIZE(ptr) (((toast_compress_header *) (ptr))->rawsize)
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#define TOAST_COMPRESS_RAWDATA(ptr) \
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(((char *) (ptr)) + TOAST_COMPRESS_HDRSZ)
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#define TOAST_COMPRESS_SET_RAWSIZE(ptr, len) \
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(((toast_compress_header *) (ptr))->rawsize = (len))
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extern Datum toast_compress_datum(Datum value);
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extern Oid toast_get_valid_index(Oid toastoid, LOCKMODE lock);
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extern void toast_delete_datum(Relation rel, Datum value, bool is_speculative);
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extern Datum toast_save_datum(Relation rel, Datum value,
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struct varlena *oldexternal, int options);
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extern int toast_open_indexes(Relation toastrel,
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LOCKMODE lock,
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Relation **toastidxs,
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int *num_indexes);
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extern void toast_close_indexes(Relation *toastidxs, int num_indexes,
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LOCKMODE lock);
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extern void init_toast_snapshot(Snapshot toast_snapshot);
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#endif /* TOAST_INTERNALS_H */
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