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https://git.postgresql.org/git/postgresql.git
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4baaf863ec
Backpatch certain files through 9.0
2180 lines
58 KiB
C
2180 lines
58 KiB
C
/*-------------------------------------------------------------------------
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*
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* tuptoaster.c
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* Support routines for external and compressed storage of
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* variable size attributes.
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*
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* Copyright (c) 2000-2015, PostgreSQL Global Development Group
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*
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*
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* IDENTIFICATION
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* src/backend/access/heap/tuptoaster.c
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*
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*
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* INTERFACE ROUTINES
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* toast_insert_or_update -
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* Try to make a given tuple fit into one page by compressing
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* or moving off attributes
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*
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* toast_delete -
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* Reclaim toast storage when a tuple is deleted
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*
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* heap_tuple_untoast_attr -
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* Fetch back a given value from the "secondary" relation
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <unistd.h>
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#include <fcntl.h>
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#include "access/genam.h"
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#include "access/heapam.h"
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#include "access/tuptoaster.h"
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#include "access/xact.h"
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#include "catalog/catalog.h"
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#include "miscadmin.h"
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#include "utils/fmgroids.h"
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#include "utils/pg_lzcompress.h"
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#include "utils/rel.h"
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#include "utils/typcache.h"
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#include "utils/tqual.h"
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#undef TOAST_DEBUG
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static void toast_delete_datum(Relation rel, Datum value);
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static Datum toast_save_datum(Relation rel, Datum value,
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struct varlena * oldexternal, int options);
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static bool toastrel_valueid_exists(Relation toastrel, Oid valueid);
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static bool toastid_valueid_exists(Oid toastrelid, Oid valueid);
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static struct varlena *toast_fetch_datum(struct varlena * attr);
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static struct varlena *toast_fetch_datum_slice(struct varlena * attr,
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int32 sliceoffset, int32 length);
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static 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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static void toast_close_indexes(Relation *toastidxs, int num_indexes,
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LOCKMODE lock);
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/* ----------
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* heap_tuple_fetch_attr -
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*
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* Public entry point to get back a toasted value from
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* external source (possibly still in compressed format).
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*
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* This will return a datum that contains all the data internally, ie, not
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* relying on external storage or memory, but it can still be compressed or
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* have a short header.
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----------
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*/
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struct varlena *
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heap_tuple_fetch_attr(struct varlena * attr)
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{
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struct varlena *result;
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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{
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/*
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* This is an external stored plain value
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*/
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result = toast_fetch_datum(attr);
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}
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr))
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{
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/*
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* copy into the caller's memory context. That's not required in all
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* cases but sufficient for now since this is mainly used when we need
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* to persist a Datum for unusually long time, like in a HOLD cursor.
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*/
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struct varatt_indirect redirect;
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VARATT_EXTERNAL_GET_POINTER(redirect, attr);
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attr = (struct varlena *) redirect.pointer;
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/* nested indirect Datums aren't allowed */
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr));
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/* doesn't make much sense, but better handle it */
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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return heap_tuple_fetch_attr(attr);
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/* copy datum verbatim */
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result = (struct varlena *) palloc(VARSIZE_ANY(attr));
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memcpy(result, attr, VARSIZE_ANY(attr));
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}
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else
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{
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/*
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* This is a plain value inside of the main tuple - why am I called?
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*/
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result = attr;
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}
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return result;
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}
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/* ----------
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* heap_tuple_untoast_attr -
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*
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* Public entry point to get back a toasted value from compression
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* or external storage.
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* ----------
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*/
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struct varlena *
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heap_tuple_untoast_attr(struct varlena * attr)
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{
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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{
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/*
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* This is an externally stored datum --- fetch it back from there
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*/
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attr = toast_fetch_datum(attr);
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/* If it's compressed, decompress it */
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if (VARATT_IS_COMPRESSED(attr))
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{
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PGLZ_Header *tmp = (PGLZ_Header *) attr;
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attr = (struct varlena *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
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SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
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pglz_decompress(tmp, VARDATA(attr));
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pfree(tmp);
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}
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}
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr))
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{
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struct varatt_indirect redirect;
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VARATT_EXTERNAL_GET_POINTER(redirect, attr);
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attr = (struct varlena *) redirect.pointer;
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/* nested indirect Datums aren't allowed */
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr));
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attr = heap_tuple_untoast_attr(attr);
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}
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else if (VARATT_IS_COMPRESSED(attr))
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{
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/*
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* This is a compressed value inside of the main tuple
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*/
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PGLZ_Header *tmp = (PGLZ_Header *) attr;
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attr = (struct varlena *) palloc(PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
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SET_VARSIZE(attr, PGLZ_RAW_SIZE(tmp) + VARHDRSZ);
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pglz_decompress(tmp, VARDATA(attr));
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}
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else if (VARATT_IS_SHORT(attr))
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{
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/*
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* This is a short-header varlena --- convert to 4-byte header format
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*/
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Size data_size = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT;
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Size new_size = data_size + VARHDRSZ;
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struct varlena *new_attr;
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new_attr = (struct varlena *) palloc(new_size);
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SET_VARSIZE(new_attr, new_size);
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memcpy(VARDATA(new_attr), VARDATA_SHORT(attr), data_size);
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attr = new_attr;
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}
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return attr;
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}
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/* ----------
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* heap_tuple_untoast_attr_slice -
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*
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* Public entry point to get back part of a toasted value
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* from compression or external storage.
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* ----------
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*/
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struct varlena *
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heap_tuple_untoast_attr_slice(struct varlena * attr,
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int32 sliceoffset, int32 slicelength)
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{
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struct varlena *preslice;
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struct varlena *result;
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char *attrdata;
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int32 attrsize;
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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{
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struct varatt_external toast_pointer;
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
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/* fast path for non-compressed external datums */
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if (!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
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return toast_fetch_datum_slice(attr, sliceoffset, slicelength);
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/* fetch it back (compressed marker will get set automatically) */
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preslice = toast_fetch_datum(attr);
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}
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr))
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{
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struct varatt_indirect redirect;
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VARATT_EXTERNAL_GET_POINTER(redirect, attr);
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/* nested indirect Datums aren't allowed */
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(redirect.pointer));
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return heap_tuple_untoast_attr_slice(redirect.pointer,
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sliceoffset, slicelength);
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}
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else
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preslice = attr;
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if (VARATT_IS_COMPRESSED(preslice))
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{
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PGLZ_Header *tmp = (PGLZ_Header *) preslice;
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Size size = PGLZ_RAW_SIZE(tmp) + VARHDRSZ;
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preslice = (struct varlena *) palloc(size);
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SET_VARSIZE(preslice, size);
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pglz_decompress(tmp, VARDATA(preslice));
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if (tmp != (PGLZ_Header *) attr)
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pfree(tmp);
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}
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if (VARATT_IS_SHORT(preslice))
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{
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attrdata = VARDATA_SHORT(preslice);
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attrsize = VARSIZE_SHORT(preslice) - VARHDRSZ_SHORT;
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}
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else
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{
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attrdata = VARDATA(preslice);
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attrsize = VARSIZE(preslice) - VARHDRSZ;
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}
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/* slicing of datum for compressed cases and plain value */
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if (sliceoffset >= attrsize)
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{
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sliceoffset = 0;
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slicelength = 0;
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}
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if (((sliceoffset + slicelength) > attrsize) || slicelength < 0)
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slicelength = attrsize - sliceoffset;
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result = (struct varlena *) palloc(slicelength + VARHDRSZ);
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SET_VARSIZE(result, slicelength + VARHDRSZ);
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memcpy(VARDATA(result), attrdata + sliceoffset, slicelength);
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if (preslice != attr)
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pfree(preslice);
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return result;
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}
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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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* (including the VARHDRSZ header)
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* ----------
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*/
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Size
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toast_raw_datum_size(Datum value)
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{
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struct varlena *attr = (struct varlena *) DatumGetPointer(value);
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Size result;
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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{
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/* va_rawsize is the size of the original datum -- including header */
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struct varatt_external toast_pointer;
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
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result = toast_pointer.va_rawsize;
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}
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr))
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{
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struct varatt_indirect toast_pointer;
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
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/* nested indirect Datums aren't allowed */
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(toast_pointer.pointer));
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return toast_raw_datum_size(PointerGetDatum(toast_pointer.pointer));
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}
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else if (VARATT_IS_COMPRESSED(attr))
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{
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/* here, va_rawsize is just the payload size */
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result = VARRAWSIZE_4B_C(attr) + VARHDRSZ;
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}
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else if (VARATT_IS_SHORT(attr))
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{
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/*
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* we have to normalize the header length to VARHDRSZ or else the
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* callers of this function will be confused.
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*/
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result = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT + VARHDRSZ;
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}
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else
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{
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/* plain untoasted datum */
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result = VARSIZE(attr);
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}
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return result;
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}
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/* ----------
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* toast_datum_size
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*
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* Return the physical storage size (possibly compressed) of a varlena datum
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* ----------
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*/
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Size
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toast_datum_size(Datum value)
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{
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struct varlena *attr = (struct varlena *) DatumGetPointer(value);
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Size result;
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if (VARATT_IS_EXTERNAL_ONDISK(attr))
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{
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/*
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* Attribute is stored externally - return the extsize whether
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* compressed or not. We do not count the size of the toast pointer
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* ... should we?
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*/
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struct varatt_external toast_pointer;
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
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result = toast_pointer.va_extsize;
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}
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr))
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{
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struct varatt_indirect toast_pointer;
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
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/* nested indirect Datums aren't allowed */
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr));
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return toast_datum_size(PointerGetDatum(toast_pointer.pointer));
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}
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else if (VARATT_IS_SHORT(attr))
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{
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result = VARSIZE_SHORT(attr);
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}
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else
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{
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/*
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* Attribute is stored inline either compressed or not, just calculate
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* the size of the datum in either case.
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*/
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result = VARSIZE(attr);
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}
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return result;
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}
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/* ----------
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* toast_delete -
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*
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* Cascaded delete toast-entries on DELETE
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* ----------
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*/
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void
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toast_delete(Relation rel, HeapTuple oldtup)
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{
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TupleDesc tupleDesc;
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Form_pg_attribute *att;
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int numAttrs;
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int i;
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Datum toast_values[MaxHeapAttributeNumber];
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bool toast_isnull[MaxHeapAttributeNumber];
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/*
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* We should only ever be called for tuples of plain relations or
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* materialized views --- recursing on a toast rel is bad news.
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*/
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Assert(rel->rd_rel->relkind == RELKIND_RELATION ||
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rel->rd_rel->relkind == RELKIND_MATVIEW);
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/*
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* Get the tuple descriptor and break down the tuple into fields.
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*
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* NOTE: it's debatable whether to use heap_deform_tuple() here or just
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* heap_getattr() only the varlena columns. The latter could win if there
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* are few varlena columns and many non-varlena ones. However,
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* heap_deform_tuple costs only O(N) while the heap_getattr way would cost
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* O(N^2) if there are many varlena columns, so it seems better to err on
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* the side of linear cost. (We won't even be here unless there's at
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* least one varlena column, by the way.)
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*/
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tupleDesc = rel->rd_att;
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att = tupleDesc->attrs;
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numAttrs = tupleDesc->natts;
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Assert(numAttrs <= MaxHeapAttributeNumber);
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heap_deform_tuple(oldtup, tupleDesc, toast_values, toast_isnull);
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/*
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* Check for external stored attributes and delete them from the secondary
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* relation.
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*/
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for (i = 0; i < numAttrs; i++)
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{
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if (att[i]->attlen == -1)
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{
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Datum value = toast_values[i];
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if (toast_isnull[i])
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continue;
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else if (VARATT_IS_EXTERNAL_ONDISK(PointerGetDatum(value)))
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toast_delete_datum(rel, value);
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else if (VARATT_IS_EXTERNAL_INDIRECT(PointerGetDatum(value)))
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elog(ERROR, "attempt to delete tuple containing indirect datums");
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}
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}
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}
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/* ----------
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* toast_insert_or_update -
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*
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* Delete no-longer-used toast-entries and create new ones to
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* make the new tuple fit on INSERT or UPDATE
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*
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* Inputs:
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* newtup: the candidate new tuple to be inserted
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* oldtup: the old row version for UPDATE, or NULL for INSERT
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* options: options to be passed to heap_insert() for toast rows
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* Result:
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* either newtup if no toasting is needed, or a palloc'd modified tuple
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* that is what should actually get stored
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*
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* NOTE: neither newtup nor oldtup will be modified. This is a change
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* from the pre-8.1 API of this routine.
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* ----------
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*/
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HeapTuple
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toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup,
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int options)
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{
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HeapTuple result_tuple;
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TupleDesc tupleDesc;
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Form_pg_attribute *att;
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int numAttrs;
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int i;
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bool need_change = false;
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bool need_free = false;
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bool need_delold = false;
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bool has_nulls = false;
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Size maxDataLen;
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Size hoff;
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char toast_action[MaxHeapAttributeNumber];
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bool toast_isnull[MaxHeapAttributeNumber];
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bool toast_oldisnull[MaxHeapAttributeNumber];
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Datum toast_values[MaxHeapAttributeNumber];
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Datum toast_oldvalues[MaxHeapAttributeNumber];
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struct varlena *toast_oldexternal[MaxHeapAttributeNumber];
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int32 toast_sizes[MaxHeapAttributeNumber];
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bool toast_free[MaxHeapAttributeNumber];
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bool toast_delold[MaxHeapAttributeNumber];
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|
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/*
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|
* We should only ever be called for tuples of plain relations or
|
|
* materialized views --- recursing on a toast rel is bad news.
|
|
*/
|
|
Assert(rel->rd_rel->relkind == RELKIND_RELATION ||
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rel->rd_rel->relkind == RELKIND_MATVIEW);
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|
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/*
|
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* Get the tuple descriptor and break down the tuple(s) into fields.
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*/
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tupleDesc = rel->rd_att;
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att = tupleDesc->attrs;
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numAttrs = tupleDesc->natts;
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Assert(numAttrs <= MaxHeapAttributeNumber);
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heap_deform_tuple(newtup, tupleDesc, toast_values, toast_isnull);
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if (oldtup != NULL)
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heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull);
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/* ----------
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* Then collect information about the values given
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*
|
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* NOTE: toast_action[i] can have these values:
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* ' ' default handling
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* 'p' already processed --- don't touch it
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* 'x' incompressible, but OK to move off
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*
|
|
* NOTE: toast_sizes[i] is only made valid for varlena attributes with
|
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* toast_action[i] different from 'p'.
|
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* ----------
|
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*/
|
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memset(toast_action, ' ', numAttrs * sizeof(char));
|
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memset(toast_oldexternal, 0, numAttrs * sizeof(struct varlena *));
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memset(toast_free, 0, numAttrs * sizeof(bool));
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memset(toast_delold, 0, numAttrs * sizeof(bool));
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|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
struct varlena *old_value;
|
|
struct varlena *new_value;
|
|
|
|
if (oldtup != NULL)
|
|
{
|
|
/*
|
|
* For UPDATE get the old and new values of this attribute
|
|
*/
|
|
old_value = (struct varlena *) DatumGetPointer(toast_oldvalues[i]);
|
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
|
|
|
|
/*
|
|
* If the old value is stored on disk, check if it has changed so
|
|
* we have to delete it later.
|
|
*/
|
|
if (att[i]->attlen == -1 && !toast_oldisnull[i] &&
|
|
VARATT_IS_EXTERNAL_ONDISK(old_value))
|
|
{
|
|
if (toast_isnull[i] || !VARATT_IS_EXTERNAL_ONDISK(new_value) ||
|
|
memcmp((char *) old_value, (char *) new_value,
|
|
VARSIZE_EXTERNAL(old_value)) != 0)
|
|
{
|
|
/*
|
|
* The old external stored value isn't needed any more
|
|
* after the update
|
|
*/
|
|
toast_delold[i] = true;
|
|
need_delold = true;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* This attribute isn't changed by this update so we reuse
|
|
* the original reference to the old value in the new
|
|
* tuple.
|
|
*/
|
|
toast_action[i] = 'p';
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* For INSERT simply get the new value
|
|
*/
|
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
|
|
}
|
|
|
|
/*
|
|
* Handle NULL attributes
|
|
*/
|
|
if (toast_isnull[i])
|
|
{
|
|
toast_action[i] = 'p';
|
|
has_nulls = true;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Now look at varlena attributes
|
|
*/
|
|
if (att[i]->attlen == -1)
|
|
{
|
|
/*
|
|
* If the table's attribute says PLAIN always, force it so.
|
|
*/
|
|
if (att[i]->attstorage == 'p')
|
|
toast_action[i] = 'p';
|
|
|
|
/*
|
|
* We took care of UPDATE above, so any external value we find
|
|
* still in the tuple must be someone else's we cannot reuse.
|
|
* Fetch it back (without decompression, unless we are forcing
|
|
* PLAIN storage). If necessary, we'll push it out as a new
|
|
* external value below.
|
|
*/
|
|
if (VARATT_IS_EXTERNAL(new_value))
|
|
{
|
|
toast_oldexternal[i] = new_value;
|
|
if (att[i]->attstorage == 'p')
|
|
new_value = heap_tuple_untoast_attr(new_value);
|
|
else
|
|
new_value = heap_tuple_fetch_attr(new_value);
|
|
toast_values[i] = PointerGetDatum(new_value);
|
|
toast_free[i] = true;
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
|
|
/*
|
|
* Remember the size of this attribute
|
|
*/
|
|
toast_sizes[i] = VARSIZE_ANY(new_value);
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* Not a varlena attribute, plain storage always
|
|
*/
|
|
toast_action[i] = 'p';
|
|
}
|
|
}
|
|
|
|
/* ----------
|
|
* Compress and/or save external until data fits into target length
|
|
*
|
|
* 1: Inline compress attributes with attstorage 'x', and store very
|
|
* large attributes with attstorage 'x' or 'e' external immediately
|
|
* 2: Store attributes with attstorage 'x' or 'e' external
|
|
* 3: Inline compress attributes with attstorage 'm'
|
|
* 4: Store attributes with attstorage 'm' external
|
|
* ----------
|
|
*/
|
|
|
|
/* compute header overhead --- this should match heap_form_tuple() */
|
|
hoff = offsetof(HeapTupleHeaderData, t_bits);
|
|
if (has_nulls)
|
|
hoff += BITMAPLEN(numAttrs);
|
|
if (newtup->t_data->t_infomask & HEAP_HASOID)
|
|
hoff += sizeof(Oid);
|
|
hoff = MAXALIGN(hoff);
|
|
/* now convert to a limit on the tuple data size */
|
|
maxDataLen = TOAST_TUPLE_TARGET - hoff;
|
|
|
|
/*
|
|
* Look for attributes with attstorage 'x' to compress. Also find large
|
|
* attributes with attstorage 'x' or 'e', and store them external.
|
|
*/
|
|
while (heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull) > maxDataLen)
|
|
{
|
|
int biggest_attno = -1;
|
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
|
|
Datum old_value;
|
|
Datum new_value;
|
|
|
|
/*
|
|
* Search for the biggest yet unprocessed internal attribute
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
if (toast_action[i] != ' ')
|
|
continue;
|
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
|
|
continue; /* can't happen, toast_action would be 'p' */
|
|
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i])))
|
|
continue;
|
|
if (att[i]->attstorage != 'x' && att[i]->attstorage != 'e')
|
|
continue;
|
|
if (toast_sizes[i] > biggest_size)
|
|
{
|
|
biggest_attno = i;
|
|
biggest_size = toast_sizes[i];
|
|
}
|
|
}
|
|
|
|
if (biggest_attno < 0)
|
|
break;
|
|
|
|
/*
|
|
* Attempt to compress it inline, if it has attstorage 'x'
|
|
*/
|
|
i = biggest_attno;
|
|
if (att[i]->attstorage == 'x')
|
|
{
|
|
old_value = toast_values[i];
|
|
new_value = toast_compress_datum(old_value);
|
|
|
|
if (DatumGetPointer(new_value) != NULL)
|
|
{
|
|
/* successful compression */
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(old_value));
|
|
toast_values[i] = new_value;
|
|
toast_free[i] = true;
|
|
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i]));
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
else
|
|
{
|
|
/* incompressible, ignore on subsequent compression passes */
|
|
toast_action[i] = 'x';
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* has attstorage 'e', ignore on subsequent compression passes */
|
|
toast_action[i] = 'x';
|
|
}
|
|
|
|
/*
|
|
* If this value is by itself more than maxDataLen (after compression
|
|
* if any), push it out to the toast table immediately, if possible.
|
|
* This avoids uselessly compressing other fields in the common case
|
|
* where we have one long field and several short ones.
|
|
*
|
|
* XXX maybe the threshold should be less than maxDataLen?
|
|
*/
|
|
if (toast_sizes[i] > maxDataLen &&
|
|
rel->rd_rel->reltoastrelid != InvalidOid)
|
|
{
|
|
old_value = toast_values[i];
|
|
toast_action[i] = 'p';
|
|
toast_values[i] = toast_save_datum(rel, toast_values[i],
|
|
toast_oldexternal[i], options);
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(old_value));
|
|
toast_free[i] = true;
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Second we look for attributes of attstorage 'x' or 'e' that are still
|
|
* inline. But skip this if there's no toast table to push them to.
|
|
*/
|
|
while (heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull) > maxDataLen &&
|
|
rel->rd_rel->reltoastrelid != InvalidOid)
|
|
{
|
|
int biggest_attno = -1;
|
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
|
|
Datum old_value;
|
|
|
|
/*------
|
|
* Search for the biggest yet inlined attribute with
|
|
* attstorage equals 'x' or 'e'
|
|
*------
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
if (toast_action[i] == 'p')
|
|
continue;
|
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
|
|
continue; /* can't happen, toast_action would be 'p' */
|
|
if (att[i]->attstorage != 'x' && att[i]->attstorage != 'e')
|
|
continue;
|
|
if (toast_sizes[i] > biggest_size)
|
|
{
|
|
biggest_attno = i;
|
|
biggest_size = toast_sizes[i];
|
|
}
|
|
}
|
|
|
|
if (biggest_attno < 0)
|
|
break;
|
|
|
|
/*
|
|
* Store this external
|
|
*/
|
|
i = biggest_attno;
|
|
old_value = toast_values[i];
|
|
toast_action[i] = 'p';
|
|
toast_values[i] = toast_save_datum(rel, toast_values[i],
|
|
toast_oldexternal[i], options);
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(old_value));
|
|
toast_free[i] = true;
|
|
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
|
|
/*
|
|
* Round 3 - this time we take attributes with storage 'm' into
|
|
* compression
|
|
*/
|
|
while (heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull) > maxDataLen)
|
|
{
|
|
int biggest_attno = -1;
|
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
|
|
Datum old_value;
|
|
Datum new_value;
|
|
|
|
/*
|
|
* Search for the biggest yet uncompressed internal attribute
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
if (toast_action[i] != ' ')
|
|
continue;
|
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
|
|
continue; /* can't happen, toast_action would be 'p' */
|
|
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i])))
|
|
continue;
|
|
if (att[i]->attstorage != 'm')
|
|
continue;
|
|
if (toast_sizes[i] > biggest_size)
|
|
{
|
|
biggest_attno = i;
|
|
biggest_size = toast_sizes[i];
|
|
}
|
|
}
|
|
|
|
if (biggest_attno < 0)
|
|
break;
|
|
|
|
/*
|
|
* Attempt to compress it inline
|
|
*/
|
|
i = biggest_attno;
|
|
old_value = toast_values[i];
|
|
new_value = toast_compress_datum(old_value);
|
|
|
|
if (DatumGetPointer(new_value) != NULL)
|
|
{
|
|
/* successful compression */
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(old_value));
|
|
toast_values[i] = new_value;
|
|
toast_free[i] = true;
|
|
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i]));
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
else
|
|
{
|
|
/* incompressible, ignore on subsequent compression passes */
|
|
toast_action[i] = 'x';
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Finally we store attributes of type 'm' externally. At this point we
|
|
* increase the target tuple size, so that 'm' attributes aren't stored
|
|
* externally unless really necessary.
|
|
*/
|
|
maxDataLen = TOAST_TUPLE_TARGET_MAIN - hoff;
|
|
|
|
while (heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull) > maxDataLen &&
|
|
rel->rd_rel->reltoastrelid != InvalidOid)
|
|
{
|
|
int biggest_attno = -1;
|
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE);
|
|
Datum old_value;
|
|
|
|
/*--------
|
|
* Search for the biggest yet inlined attribute with
|
|
* attstorage = 'm'
|
|
*--------
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
if (toast_action[i] == 'p')
|
|
continue;
|
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i])))
|
|
continue; /* can't happen, toast_action would be 'p' */
|
|
if (att[i]->attstorage != 'm')
|
|
continue;
|
|
if (toast_sizes[i] > biggest_size)
|
|
{
|
|
biggest_attno = i;
|
|
biggest_size = toast_sizes[i];
|
|
}
|
|
}
|
|
|
|
if (biggest_attno < 0)
|
|
break;
|
|
|
|
/*
|
|
* Store this external
|
|
*/
|
|
i = biggest_attno;
|
|
old_value = toast_values[i];
|
|
toast_action[i] = 'p';
|
|
toast_values[i] = toast_save_datum(rel, toast_values[i],
|
|
toast_oldexternal[i], options);
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(old_value));
|
|
toast_free[i] = true;
|
|
|
|
need_change = true;
|
|
need_free = true;
|
|
}
|
|
|
|
/*
|
|
* In the case we toasted any values, we need to build a new heap tuple
|
|
* with the changed values.
|
|
*/
|
|
if (need_change)
|
|
{
|
|
HeapTupleHeader olddata = newtup->t_data;
|
|
HeapTupleHeader new_data;
|
|
int32 new_header_len;
|
|
int32 new_data_len;
|
|
int32 new_tuple_len;
|
|
|
|
/*
|
|
* Calculate the new size of the tuple.
|
|
*
|
|
* Note: we used to assume here that the old tuple's t_hoff must equal
|
|
* the new_header_len value, but that was incorrect. The old tuple
|
|
* might have a smaller-than-current natts, if there's been an ALTER
|
|
* TABLE ADD COLUMN since it was stored; and that would lead to a
|
|
* different conclusion about the size of the null bitmap, or even
|
|
* whether there needs to be one at all.
|
|
*/
|
|
new_header_len = offsetof(HeapTupleHeaderData, t_bits);
|
|
if (has_nulls)
|
|
new_header_len += BITMAPLEN(numAttrs);
|
|
if (olddata->t_infomask & HEAP_HASOID)
|
|
new_header_len += sizeof(Oid);
|
|
new_header_len = MAXALIGN(new_header_len);
|
|
new_data_len = heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull);
|
|
new_tuple_len = new_header_len + new_data_len;
|
|
|
|
/*
|
|
* Allocate and zero the space needed, and fill HeapTupleData fields.
|
|
*/
|
|
result_tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + new_tuple_len);
|
|
result_tuple->t_len = new_tuple_len;
|
|
result_tuple->t_self = newtup->t_self;
|
|
result_tuple->t_tableOid = newtup->t_tableOid;
|
|
new_data = (HeapTupleHeader) ((char *) result_tuple + HEAPTUPLESIZE);
|
|
result_tuple->t_data = new_data;
|
|
|
|
/*
|
|
* Copy the existing tuple header, but adjust natts and t_hoff.
|
|
*/
|
|
memcpy(new_data, olddata, offsetof(HeapTupleHeaderData, t_bits));
|
|
HeapTupleHeaderSetNatts(new_data, numAttrs);
|
|
new_data->t_hoff = new_header_len;
|
|
if (olddata->t_infomask & HEAP_HASOID)
|
|
HeapTupleHeaderSetOid(new_data, HeapTupleHeaderGetOid(olddata));
|
|
|
|
/* Copy over the data, and fill the null bitmap if needed */
|
|
heap_fill_tuple(tupleDesc,
|
|
toast_values,
|
|
toast_isnull,
|
|
(char *) new_data + new_header_len,
|
|
new_data_len,
|
|
&(new_data->t_infomask),
|
|
has_nulls ? new_data->t_bits : NULL);
|
|
}
|
|
else
|
|
result_tuple = newtup;
|
|
|
|
/*
|
|
* Free allocated temp values
|
|
*/
|
|
if (need_free)
|
|
for (i = 0; i < numAttrs; i++)
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(toast_values[i]));
|
|
|
|
/*
|
|
* Delete external values from the old tuple
|
|
*/
|
|
if (need_delold)
|
|
for (i = 0; i < numAttrs; i++)
|
|
if (toast_delold[i])
|
|
toast_delete_datum(rel, toast_oldvalues[i]);
|
|
|
|
return result_tuple;
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_flatten_tuple -
|
|
*
|
|
* "Flatten" a tuple to contain no out-of-line toasted fields.
|
|
* (This does not eliminate compressed or short-header datums.)
|
|
*
|
|
* Note: we expect the caller already checked HeapTupleHasExternal(tup),
|
|
* so there is no need for a short-circuit path.
|
|
* ----------
|
|
*/
|
|
HeapTuple
|
|
toast_flatten_tuple(HeapTuple tup, TupleDesc tupleDesc)
|
|
{
|
|
HeapTuple new_tuple;
|
|
Form_pg_attribute *att = tupleDesc->attrs;
|
|
int numAttrs = tupleDesc->natts;
|
|
int i;
|
|
Datum toast_values[MaxTupleAttributeNumber];
|
|
bool toast_isnull[MaxTupleAttributeNumber];
|
|
bool toast_free[MaxTupleAttributeNumber];
|
|
|
|
/*
|
|
* Break down the tuple into fields.
|
|
*/
|
|
Assert(numAttrs <= MaxTupleAttributeNumber);
|
|
heap_deform_tuple(tup, tupleDesc, toast_values, toast_isnull);
|
|
|
|
memset(toast_free, 0, numAttrs * sizeof(bool));
|
|
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
/*
|
|
* Look at non-null varlena attributes
|
|
*/
|
|
if (!toast_isnull[i] && att[i]->attlen == -1)
|
|
{
|
|
struct varlena *new_value;
|
|
|
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
|
|
if (VARATT_IS_EXTERNAL(new_value))
|
|
{
|
|
new_value = toast_fetch_datum(new_value);
|
|
toast_values[i] = PointerGetDatum(new_value);
|
|
toast_free[i] = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Form the reconfigured tuple.
|
|
*/
|
|
new_tuple = heap_form_tuple(tupleDesc, toast_values, toast_isnull);
|
|
|
|
/*
|
|
* Be sure to copy the tuple's OID and identity fields. We also make a
|
|
* point of copying visibility info, just in case anybody looks at those
|
|
* fields in a syscache entry.
|
|
*/
|
|
if (tupleDesc->tdhasoid)
|
|
HeapTupleSetOid(new_tuple, HeapTupleGetOid(tup));
|
|
|
|
new_tuple->t_self = tup->t_self;
|
|
new_tuple->t_tableOid = tup->t_tableOid;
|
|
|
|
new_tuple->t_data->t_choice = tup->t_data->t_choice;
|
|
new_tuple->t_data->t_ctid = tup->t_data->t_ctid;
|
|
new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
|
|
new_tuple->t_data->t_infomask |=
|
|
tup->t_data->t_infomask & HEAP_XACT_MASK;
|
|
new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
|
|
new_tuple->t_data->t_infomask2 |=
|
|
tup->t_data->t_infomask2 & HEAP2_XACT_MASK;
|
|
|
|
/*
|
|
* Free allocated temp values
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(toast_values[i]));
|
|
|
|
return new_tuple;
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_flatten_tuple_to_datum -
|
|
*
|
|
* "Flatten" a tuple containing out-of-line toasted fields into a Datum.
|
|
* The result is always palloc'd in the current memory context.
|
|
*
|
|
* We have a general rule that Datums of container types (rows, arrays,
|
|
* ranges, etc) must not contain any external TOAST pointers. Without
|
|
* this rule, we'd have to look inside each Datum when preparing a tuple
|
|
* for storage, which would be expensive and would fail to extend cleanly
|
|
* to new sorts of container types.
|
|
*
|
|
* However, we don't want to say that tuples represented as HeapTuples
|
|
* can't contain toasted fields, so instead this routine should be called
|
|
* when such a HeapTuple is being converted into a Datum.
|
|
*
|
|
* While we're at it, we decompress any compressed fields too. This is not
|
|
* necessary for correctness, but reflects an expectation that compression
|
|
* will be more effective if applied to the whole tuple not individual
|
|
* fields. We are not so concerned about that that we want to deconstruct
|
|
* and reconstruct tuples just to get rid of compressed fields, however.
|
|
* So callers typically won't call this unless they see that the tuple has
|
|
* at least one external field.
|
|
*
|
|
* On the other hand, in-line short-header varlena fields are left alone.
|
|
* If we "untoasted" them here, they'd just get changed back to short-header
|
|
* format anyway within heap_fill_tuple.
|
|
* ----------
|
|
*/
|
|
Datum
|
|
toast_flatten_tuple_to_datum(HeapTupleHeader tup,
|
|
uint32 tup_len,
|
|
TupleDesc tupleDesc)
|
|
{
|
|
HeapTupleHeader new_data;
|
|
int32 new_header_len;
|
|
int32 new_data_len;
|
|
int32 new_tuple_len;
|
|
HeapTupleData tmptup;
|
|
Form_pg_attribute *att = tupleDesc->attrs;
|
|
int numAttrs = tupleDesc->natts;
|
|
int i;
|
|
bool has_nulls = false;
|
|
Datum toast_values[MaxTupleAttributeNumber];
|
|
bool toast_isnull[MaxTupleAttributeNumber];
|
|
bool toast_free[MaxTupleAttributeNumber];
|
|
|
|
/* Build a temporary HeapTuple control structure */
|
|
tmptup.t_len = tup_len;
|
|
ItemPointerSetInvalid(&(tmptup.t_self));
|
|
tmptup.t_tableOid = InvalidOid;
|
|
tmptup.t_data = tup;
|
|
|
|
/*
|
|
* Break down the tuple into fields.
|
|
*/
|
|
Assert(numAttrs <= MaxTupleAttributeNumber);
|
|
heap_deform_tuple(&tmptup, tupleDesc, toast_values, toast_isnull);
|
|
|
|
memset(toast_free, 0, numAttrs * sizeof(bool));
|
|
|
|
for (i = 0; i < numAttrs; i++)
|
|
{
|
|
/*
|
|
* Look at non-null varlena attributes
|
|
*/
|
|
if (toast_isnull[i])
|
|
has_nulls = true;
|
|
else if (att[i]->attlen == -1)
|
|
{
|
|
struct varlena *new_value;
|
|
|
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]);
|
|
if (VARATT_IS_EXTERNAL(new_value) ||
|
|
VARATT_IS_COMPRESSED(new_value))
|
|
{
|
|
new_value = heap_tuple_untoast_attr(new_value);
|
|
toast_values[i] = PointerGetDatum(new_value);
|
|
toast_free[i] = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Calculate the new size of the tuple.
|
|
*
|
|
* This should match the reconstruction code in toast_insert_or_update.
|
|
*/
|
|
new_header_len = offsetof(HeapTupleHeaderData, t_bits);
|
|
if (has_nulls)
|
|
new_header_len += BITMAPLEN(numAttrs);
|
|
if (tup->t_infomask & HEAP_HASOID)
|
|
new_header_len += sizeof(Oid);
|
|
new_header_len = MAXALIGN(new_header_len);
|
|
new_data_len = heap_compute_data_size(tupleDesc,
|
|
toast_values, toast_isnull);
|
|
new_tuple_len = new_header_len + new_data_len;
|
|
|
|
new_data = (HeapTupleHeader) palloc0(new_tuple_len);
|
|
|
|
/*
|
|
* Copy the existing tuple header, but adjust natts and t_hoff.
|
|
*/
|
|
memcpy(new_data, tup, offsetof(HeapTupleHeaderData, t_bits));
|
|
HeapTupleHeaderSetNatts(new_data, numAttrs);
|
|
new_data->t_hoff = new_header_len;
|
|
if (tup->t_infomask & HEAP_HASOID)
|
|
HeapTupleHeaderSetOid(new_data, HeapTupleHeaderGetOid(tup));
|
|
|
|
/* Set the composite-Datum header fields correctly */
|
|
HeapTupleHeaderSetDatumLength(new_data, new_tuple_len);
|
|
HeapTupleHeaderSetTypeId(new_data, tupleDesc->tdtypeid);
|
|
HeapTupleHeaderSetTypMod(new_data, tupleDesc->tdtypmod);
|
|
|
|
/* Copy over the data, and fill the null bitmap if needed */
|
|
heap_fill_tuple(tupleDesc,
|
|
toast_values,
|
|
toast_isnull,
|
|
(char *) new_data + new_header_len,
|
|
new_data_len,
|
|
&(new_data->t_infomask),
|
|
has_nulls ? new_data->t_bits : NULL);
|
|
|
|
/*
|
|
* Free allocated temp values
|
|
*/
|
|
for (i = 0; i < numAttrs; i++)
|
|
if (toast_free[i])
|
|
pfree(DatumGetPointer(toast_values[i]));
|
|
|
|
return PointerGetDatum(new_data);
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_compress_datum -
|
|
*
|
|
* Create a compressed version of a varlena datum
|
|
*
|
|
* If we fail (ie, compressed result is actually bigger than original)
|
|
* then return NULL. We must not use compressed data if it'd expand
|
|
* the tuple!
|
|
*
|
|
* We use VAR{SIZE,DATA}_ANY so we can handle short varlenas here without
|
|
* copying them. But we can't handle external or compressed datums.
|
|
* ----------
|
|
*/
|
|
Datum
|
|
toast_compress_datum(Datum value)
|
|
{
|
|
struct varlena *tmp;
|
|
int32 valsize = VARSIZE_ANY_EXHDR(DatumGetPointer(value));
|
|
|
|
Assert(!VARATT_IS_EXTERNAL(DatumGetPointer(value)));
|
|
Assert(!VARATT_IS_COMPRESSED(DatumGetPointer(value)));
|
|
|
|
/*
|
|
* No point in wasting a palloc cycle if value size is out of the allowed
|
|
* range for compression
|
|
*/
|
|
if (valsize < PGLZ_strategy_default->min_input_size ||
|
|
valsize > PGLZ_strategy_default->max_input_size)
|
|
return PointerGetDatum(NULL);
|
|
|
|
tmp = (struct varlena *) palloc(PGLZ_MAX_OUTPUT(valsize));
|
|
|
|
/*
|
|
* We recheck the actual size even if pglz_compress() reports success,
|
|
* because it might be satisfied with having saved as little as one byte
|
|
* in the compressed data --- which could turn into a net loss once you
|
|
* consider header and alignment padding. Worst case, the compressed
|
|
* format might require three padding bytes (plus header, which is
|
|
* included in VARSIZE(tmp)), whereas the uncompressed format would take
|
|
* only one header byte and no padding if the value is short enough. So
|
|
* we insist on a savings of more than 2 bytes to ensure we have a gain.
|
|
*/
|
|
if (pglz_compress(VARDATA_ANY(DatumGetPointer(value)), valsize,
|
|
(PGLZ_Header *) tmp, PGLZ_strategy_default) &&
|
|
VARSIZE(tmp) < valsize - 2)
|
|
{
|
|
/* successful compression */
|
|
return PointerGetDatum(tmp);
|
|
}
|
|
else
|
|
{
|
|
/* incompressible data */
|
|
pfree(tmp);
|
|
return PointerGetDatum(NULL);
|
|
}
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_get_valid_index
|
|
*
|
|
* Get OID of valid index associated to given toast relation. A toast
|
|
* relation can have only one valid index at the same time.
|
|
*/
|
|
Oid
|
|
toast_get_valid_index(Oid toastoid, LOCKMODE lock)
|
|
{
|
|
int num_indexes;
|
|
int validIndex;
|
|
Oid validIndexOid;
|
|
Relation *toastidxs;
|
|
Relation toastrel;
|
|
|
|
/* Open the toast relation */
|
|
toastrel = heap_open(toastoid, lock);
|
|
|
|
/* Look for the valid index of the toast relation */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
lock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
validIndexOid = RelationGetRelid(toastidxs[validIndex]);
|
|
|
|
/* Close the toast relation and all its indexes */
|
|
toast_close_indexes(toastidxs, num_indexes, lock);
|
|
heap_close(toastrel, lock);
|
|
|
|
return validIndexOid;
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_save_datum -
|
|
*
|
|
* Save one single datum into the secondary relation and return
|
|
* a Datum reference for it.
|
|
*
|
|
* rel: the main relation we're working with (not the toast rel!)
|
|
* value: datum to be pushed to toast storage
|
|
* oldexternal: if not NULL, toast pointer previously representing the datum
|
|
* options: options to be passed to heap_insert() for toast rows
|
|
* ----------
|
|
*/
|
|
static Datum
|
|
toast_save_datum(Relation rel, Datum value,
|
|
struct varlena * oldexternal, int options)
|
|
{
|
|
Relation toastrel;
|
|
Relation *toastidxs;
|
|
HeapTuple toasttup;
|
|
TupleDesc toasttupDesc;
|
|
Datum t_values[3];
|
|
bool t_isnull[3];
|
|
CommandId mycid = GetCurrentCommandId(true);
|
|
struct varlena *result;
|
|
struct varatt_external toast_pointer;
|
|
struct
|
|
{
|
|
struct varlena hdr;
|
|
char data[TOAST_MAX_CHUNK_SIZE]; /* make struct big enough */
|
|
int32 align_it; /* ensure struct is aligned well enough */
|
|
} chunk_data;
|
|
int32 chunk_size;
|
|
int32 chunk_seq = 0;
|
|
char *data_p;
|
|
int32 data_todo;
|
|
Pointer dval = DatumGetPointer(value);
|
|
int num_indexes;
|
|
int validIndex;
|
|
|
|
Assert(!VARATT_IS_EXTERNAL(value));
|
|
|
|
/*
|
|
* Open the toast relation and its indexes. We can use the index to check
|
|
* uniqueness of the OID we assign to the toasted item, even though it has
|
|
* additional columns besides OID.
|
|
*/
|
|
toastrel = heap_open(rel->rd_rel->reltoastrelid, RowExclusiveLock);
|
|
toasttupDesc = toastrel->rd_att;
|
|
|
|
/* Open all the toast indexes and look for the valid one */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
RowExclusiveLock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
|
|
/*
|
|
* Get the data pointer and length, and compute va_rawsize and va_extsize.
|
|
*
|
|
* va_rawsize is the size of the equivalent fully uncompressed datum, so
|
|
* we have to adjust for short headers.
|
|
*
|
|
* va_extsize is the actual size of the data payload in the toast records.
|
|
*/
|
|
if (VARATT_IS_SHORT(dval))
|
|
{
|
|
data_p = VARDATA_SHORT(dval);
|
|
data_todo = VARSIZE_SHORT(dval) - VARHDRSZ_SHORT;
|
|
toast_pointer.va_rawsize = data_todo + VARHDRSZ; /* as if not short */
|
|
toast_pointer.va_extsize = data_todo;
|
|
}
|
|
else if (VARATT_IS_COMPRESSED(dval))
|
|
{
|
|
data_p = VARDATA(dval);
|
|
data_todo = VARSIZE(dval) - VARHDRSZ;
|
|
/* rawsize in a compressed datum is just the size of the payload */
|
|
toast_pointer.va_rawsize = VARRAWSIZE_4B_C(dval) + VARHDRSZ;
|
|
toast_pointer.va_extsize = data_todo;
|
|
/* Assert that the numbers look like it's compressed */
|
|
Assert(VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer));
|
|
}
|
|
else
|
|
{
|
|
data_p = VARDATA(dval);
|
|
data_todo = VARSIZE(dval) - VARHDRSZ;
|
|
toast_pointer.va_rawsize = VARSIZE(dval);
|
|
toast_pointer.va_extsize = data_todo;
|
|
}
|
|
|
|
/*
|
|
* Insert the correct table OID into the result TOAST pointer.
|
|
*
|
|
* Normally this is the actual OID of the target toast table, but during
|
|
* table-rewriting operations such as CLUSTER, we have to insert the OID
|
|
* of the table's real permanent toast table instead. rd_toastoid is set
|
|
* if we have to substitute such an OID.
|
|
*/
|
|
if (OidIsValid(rel->rd_toastoid))
|
|
toast_pointer.va_toastrelid = rel->rd_toastoid;
|
|
else
|
|
toast_pointer.va_toastrelid = RelationGetRelid(toastrel);
|
|
|
|
/*
|
|
* Choose an OID to use as the value ID for this toast value.
|
|
*
|
|
* Normally we just choose an unused OID within the toast table. But
|
|
* during table-rewriting operations where we are preserving an existing
|
|
* toast table OID, we want to preserve toast value OIDs too. So, if
|
|
* rd_toastoid is set and we had a prior external value from that same
|
|
* toast table, re-use its value ID. If we didn't have a prior external
|
|
* value (which is a corner case, but possible if the table's attstorage
|
|
* options have been changed), we have to pick a value ID that doesn't
|
|
* conflict with either new or existing toast value OIDs.
|
|
*/
|
|
if (!OidIsValid(rel->rd_toastoid))
|
|
{
|
|
/* normal case: just choose an unused OID */
|
|
toast_pointer.va_valueid =
|
|
GetNewOidWithIndex(toastrel,
|
|
RelationGetRelid(toastidxs[validIndex]),
|
|
(AttrNumber) 1);
|
|
}
|
|
else
|
|
{
|
|
/* rewrite case: check to see if value was in old toast table */
|
|
toast_pointer.va_valueid = InvalidOid;
|
|
if (oldexternal != NULL)
|
|
{
|
|
struct varatt_external old_toast_pointer;
|
|
|
|
Assert(VARATT_IS_EXTERNAL_ONDISK(oldexternal));
|
|
/* Must copy to access aligned fields */
|
|
VARATT_EXTERNAL_GET_POINTER(old_toast_pointer, oldexternal);
|
|
if (old_toast_pointer.va_toastrelid == rel->rd_toastoid)
|
|
{
|
|
/* This value came from the old toast table; reuse its OID */
|
|
toast_pointer.va_valueid = old_toast_pointer.va_valueid;
|
|
|
|
/*
|
|
* There is a corner case here: the table rewrite might have
|
|
* to copy both live and recently-dead versions of a row, and
|
|
* those versions could easily reference the same toast value.
|
|
* When we copy the second or later version of such a row,
|
|
* reusing the OID will mean we select an OID that's already
|
|
* in the new toast table. Check for that, and if so, just
|
|
* fall through without writing the data again.
|
|
*
|
|
* While annoying and ugly-looking, this is a good thing
|
|
* because it ensures that we wind up with only one copy of
|
|
* the toast value when there is only one copy in the old
|
|
* toast table. Before we detected this case, we'd have made
|
|
* multiple copies, wasting space; and what's worse, the
|
|
* copies belonging to already-deleted heap tuples would not
|
|
* be reclaimed by VACUUM.
|
|
*/
|
|
if (toastrel_valueid_exists(toastrel,
|
|
toast_pointer.va_valueid))
|
|
{
|
|
/* Match, so short-circuit the data storage loop below */
|
|
data_todo = 0;
|
|
}
|
|
}
|
|
}
|
|
if (toast_pointer.va_valueid == InvalidOid)
|
|
{
|
|
/*
|
|
* new value; must choose an OID that doesn't conflict in either
|
|
* old or new toast table
|
|
*/
|
|
do
|
|
{
|
|
toast_pointer.va_valueid =
|
|
GetNewOidWithIndex(toastrel,
|
|
RelationGetRelid(toastidxs[validIndex]),
|
|
(AttrNumber) 1);
|
|
} while (toastid_valueid_exists(rel->rd_toastoid,
|
|
toast_pointer.va_valueid));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Initialize constant parts of the tuple data
|
|
*/
|
|
t_values[0] = ObjectIdGetDatum(toast_pointer.va_valueid);
|
|
t_values[2] = PointerGetDatum(&chunk_data);
|
|
t_isnull[0] = false;
|
|
t_isnull[1] = false;
|
|
t_isnull[2] = false;
|
|
|
|
/*
|
|
* Split up the item into chunks
|
|
*/
|
|
while (data_todo > 0)
|
|
{
|
|
int i;
|
|
|
|
CHECK_FOR_INTERRUPTS();
|
|
|
|
/*
|
|
* Calculate the size of this chunk
|
|
*/
|
|
chunk_size = Min(TOAST_MAX_CHUNK_SIZE, data_todo);
|
|
|
|
/*
|
|
* Build a tuple and store it
|
|
*/
|
|
t_values[1] = Int32GetDatum(chunk_seq++);
|
|
SET_VARSIZE(&chunk_data, chunk_size + VARHDRSZ);
|
|
memcpy(VARDATA(&chunk_data), data_p, chunk_size);
|
|
toasttup = heap_form_tuple(toasttupDesc, t_values, t_isnull);
|
|
|
|
heap_insert(toastrel, toasttup, mycid, options, NULL);
|
|
|
|
/*
|
|
* Create the index entry. We cheat a little here by not using
|
|
* FormIndexDatum: this relies on the knowledge that the index columns
|
|
* are the same as the initial columns of the table for all the
|
|
* indexes.
|
|
*
|
|
* Note also that there had better not be any user-created index on
|
|
* the TOAST table, since we don't bother to update anything else.
|
|
*/
|
|
for (i = 0; i < num_indexes; i++)
|
|
{
|
|
/* Only index relations marked as ready can be updated */
|
|
if (IndexIsReady(toastidxs[i]->rd_index))
|
|
index_insert(toastidxs[i], t_values, t_isnull,
|
|
&(toasttup->t_self),
|
|
toastrel,
|
|
toastidxs[i]->rd_index->indisunique ?
|
|
UNIQUE_CHECK_YES : UNIQUE_CHECK_NO);
|
|
}
|
|
|
|
/*
|
|
* Free memory
|
|
*/
|
|
heap_freetuple(toasttup);
|
|
|
|
/*
|
|
* Move on to next chunk
|
|
*/
|
|
data_todo -= chunk_size;
|
|
data_p += chunk_size;
|
|
}
|
|
|
|
/*
|
|
* Done - close toast relation and its indexes
|
|
*/
|
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock);
|
|
heap_close(toastrel, RowExclusiveLock);
|
|
|
|
/*
|
|
* Create the TOAST pointer value that we'll return
|
|
*/
|
|
result = (struct varlena *) palloc(TOAST_POINTER_SIZE);
|
|
SET_VARTAG_EXTERNAL(result, VARTAG_ONDISK);
|
|
memcpy(VARDATA_EXTERNAL(result), &toast_pointer, sizeof(toast_pointer));
|
|
|
|
return PointerGetDatum(result);
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_delete_datum -
|
|
*
|
|
* Delete a single external stored value.
|
|
* ----------
|
|
*/
|
|
static void
|
|
toast_delete_datum(Relation rel, Datum value)
|
|
{
|
|
struct varlena *attr = (struct varlena *) DatumGetPointer(value);
|
|
struct varatt_external toast_pointer;
|
|
Relation toastrel;
|
|
Relation *toastidxs;
|
|
ScanKeyData toastkey;
|
|
SysScanDesc toastscan;
|
|
HeapTuple toasttup;
|
|
int num_indexes;
|
|
int validIndex;
|
|
|
|
if (!VARATT_IS_EXTERNAL_ONDISK(attr))
|
|
return;
|
|
|
|
/* Must copy to access aligned fields */
|
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
|
|
|
|
/*
|
|
* Open the toast relation and its indexes
|
|
*/
|
|
toastrel = heap_open(toast_pointer.va_toastrelid, RowExclusiveLock);
|
|
|
|
/* Fetch valid relation used for process */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
RowExclusiveLock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
|
|
/*
|
|
* Setup a scan key to find chunks with matching va_valueid
|
|
*/
|
|
ScanKeyInit(&toastkey,
|
|
(AttrNumber) 1,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(toast_pointer.va_valueid));
|
|
|
|
/*
|
|
* Find all the chunks. (We don't actually care whether we see them in
|
|
* sequence or not, but since we've already locked the index we might as
|
|
* well use systable_beginscan_ordered.)
|
|
*/
|
|
toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex],
|
|
SnapshotToast, 1, &toastkey);
|
|
while ((toasttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL)
|
|
{
|
|
/*
|
|
* Have a chunk, delete it
|
|
*/
|
|
simple_heap_delete(toastrel, &toasttup->t_self);
|
|
}
|
|
|
|
/*
|
|
* End scan and close relations
|
|
*/
|
|
systable_endscan_ordered(toastscan);
|
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock);
|
|
heap_close(toastrel, RowExclusiveLock);
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toastrel_valueid_exists -
|
|
*
|
|
* Test whether a toast value with the given ID exists in the toast relation
|
|
* ----------
|
|
*/
|
|
static bool
|
|
toastrel_valueid_exists(Relation toastrel, Oid valueid)
|
|
{
|
|
bool result = false;
|
|
ScanKeyData toastkey;
|
|
SysScanDesc toastscan;
|
|
int num_indexes;
|
|
int validIndex;
|
|
Relation *toastidxs;
|
|
|
|
/* Fetch a valid index relation */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
RowExclusiveLock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
|
|
/*
|
|
* Setup a scan key to find chunks with matching va_valueid
|
|
*/
|
|
ScanKeyInit(&toastkey,
|
|
(AttrNumber) 1,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(valueid));
|
|
|
|
/*
|
|
* Is there any such chunk?
|
|
*/
|
|
toastscan = systable_beginscan(toastrel,
|
|
RelationGetRelid(toastidxs[validIndex]),
|
|
true, SnapshotToast, 1, &toastkey);
|
|
|
|
if (systable_getnext(toastscan) != NULL)
|
|
result = true;
|
|
|
|
systable_endscan(toastscan);
|
|
|
|
/* Clean up */
|
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock);
|
|
|
|
return result;
|
|
}
|
|
|
|
/* ----------
|
|
* toastid_valueid_exists -
|
|
*
|
|
* As above, but work from toast rel's OID not an open relation
|
|
* ----------
|
|
*/
|
|
static bool
|
|
toastid_valueid_exists(Oid toastrelid, Oid valueid)
|
|
{
|
|
bool result;
|
|
Relation toastrel;
|
|
|
|
toastrel = heap_open(toastrelid, AccessShareLock);
|
|
|
|
result = toastrel_valueid_exists(toastrel, valueid);
|
|
|
|
heap_close(toastrel, AccessShareLock);
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/* ----------
|
|
* toast_fetch_datum -
|
|
*
|
|
* Reconstruct an in memory Datum from the chunks saved
|
|
* in the toast relation
|
|
* ----------
|
|
*/
|
|
static struct varlena *
|
|
toast_fetch_datum(struct varlena * attr)
|
|
{
|
|
Relation toastrel;
|
|
Relation *toastidxs;
|
|
ScanKeyData toastkey;
|
|
SysScanDesc toastscan;
|
|
HeapTuple ttup;
|
|
TupleDesc toasttupDesc;
|
|
struct varlena *result;
|
|
struct varatt_external toast_pointer;
|
|
int32 ressize;
|
|
int32 residx,
|
|
nextidx;
|
|
int32 numchunks;
|
|
Pointer chunk;
|
|
bool isnull;
|
|
char *chunkdata;
|
|
int32 chunksize;
|
|
int num_indexes;
|
|
int validIndex;
|
|
|
|
if (VARATT_IS_EXTERNAL_INDIRECT(attr))
|
|
elog(ERROR, "shouldn't be called for indirect tuples");
|
|
|
|
/* Must copy to access aligned fields */
|
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
|
|
|
|
ressize = toast_pointer.va_extsize;
|
|
numchunks = ((ressize - 1) / TOAST_MAX_CHUNK_SIZE) + 1;
|
|
|
|
result = (struct varlena *) palloc(ressize + VARHDRSZ);
|
|
|
|
if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
|
|
SET_VARSIZE_COMPRESSED(result, ressize + VARHDRSZ);
|
|
else
|
|
SET_VARSIZE(result, ressize + VARHDRSZ);
|
|
|
|
/*
|
|
* Open the toast relation and its indexes
|
|
*/
|
|
toastrel = heap_open(toast_pointer.va_toastrelid, AccessShareLock);
|
|
toasttupDesc = toastrel->rd_att;
|
|
|
|
/* Look for the valid index of the toast relation */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
AccessShareLock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
|
|
/*
|
|
* Setup a scan key to fetch from the index by va_valueid
|
|
*/
|
|
ScanKeyInit(&toastkey,
|
|
(AttrNumber) 1,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(toast_pointer.va_valueid));
|
|
|
|
/*
|
|
* Read the chunks by index
|
|
*
|
|
* Note that because the index is actually on (valueid, chunkidx) we will
|
|
* see the chunks in chunkidx order, even though we didn't explicitly ask
|
|
* for it.
|
|
*/
|
|
nextidx = 0;
|
|
|
|
toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex],
|
|
SnapshotToast, 1, &toastkey);
|
|
while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL)
|
|
{
|
|
/*
|
|
* Have a chunk, extract the sequence number and the data
|
|
*/
|
|
residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull));
|
|
Assert(!isnull);
|
|
chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull));
|
|
Assert(!isnull);
|
|
if (!VARATT_IS_EXTENDED(chunk))
|
|
{
|
|
chunksize = VARSIZE(chunk) - VARHDRSZ;
|
|
chunkdata = VARDATA(chunk);
|
|
}
|
|
else if (VARATT_IS_SHORT(chunk))
|
|
{
|
|
/* could happen due to heap_form_tuple doing its thing */
|
|
chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT;
|
|
chunkdata = VARDATA_SHORT(chunk);
|
|
}
|
|
else
|
|
{
|
|
/* should never happen */
|
|
elog(ERROR, "found toasted toast chunk for toast value %u in %s",
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
chunksize = 0; /* keep compiler quiet */
|
|
chunkdata = NULL;
|
|
}
|
|
|
|
/*
|
|
* Some checks on the data we've found
|
|
*/
|
|
if (residx != nextidx)
|
|
elog(ERROR, "unexpected chunk number %d (expected %d) for toast value %u in %s",
|
|
residx, nextidx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
if (residx < numchunks - 1)
|
|
{
|
|
if (chunksize != TOAST_MAX_CHUNK_SIZE)
|
|
elog(ERROR, "unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s",
|
|
chunksize, (int) TOAST_MAX_CHUNK_SIZE,
|
|
residx, numchunks,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
}
|
|
else if (residx == numchunks - 1)
|
|
{
|
|
if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != ressize)
|
|
elog(ERROR, "unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s",
|
|
chunksize,
|
|
(int) (ressize - residx * TOAST_MAX_CHUNK_SIZE),
|
|
residx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
}
|
|
else
|
|
elog(ERROR, "unexpected chunk number %d (out of range %d..%d) for toast value %u in %s",
|
|
residx,
|
|
0, numchunks - 1,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
|
|
/*
|
|
* Copy the data into proper place in our result
|
|
*/
|
|
memcpy(VARDATA(result) + residx * TOAST_MAX_CHUNK_SIZE,
|
|
chunkdata,
|
|
chunksize);
|
|
|
|
nextidx++;
|
|
}
|
|
|
|
/*
|
|
* Final checks that we successfully fetched the datum
|
|
*/
|
|
if (nextidx != numchunks)
|
|
elog(ERROR, "missing chunk number %d for toast value %u in %s",
|
|
nextidx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
|
|
/*
|
|
* End scan and close relations
|
|
*/
|
|
systable_endscan_ordered(toastscan);
|
|
toast_close_indexes(toastidxs, num_indexes, AccessShareLock);
|
|
heap_close(toastrel, AccessShareLock);
|
|
|
|
return result;
|
|
}
|
|
|
|
/* ----------
|
|
* toast_fetch_datum_slice -
|
|
*
|
|
* Reconstruct a segment of a Datum from the chunks saved
|
|
* in the toast relation
|
|
* ----------
|
|
*/
|
|
static struct varlena *
|
|
toast_fetch_datum_slice(struct varlena * attr, int32 sliceoffset, int32 length)
|
|
{
|
|
Relation toastrel;
|
|
Relation *toastidxs;
|
|
ScanKeyData toastkey[3];
|
|
int nscankeys;
|
|
SysScanDesc toastscan;
|
|
HeapTuple ttup;
|
|
TupleDesc toasttupDesc;
|
|
struct varlena *result;
|
|
struct varatt_external toast_pointer;
|
|
int32 attrsize;
|
|
int32 residx;
|
|
int32 nextidx;
|
|
int numchunks;
|
|
int startchunk;
|
|
int endchunk;
|
|
int32 startoffset;
|
|
int32 endoffset;
|
|
int totalchunks;
|
|
Pointer chunk;
|
|
bool isnull;
|
|
char *chunkdata;
|
|
int32 chunksize;
|
|
int32 chcpystrt;
|
|
int32 chcpyend;
|
|
int num_indexes;
|
|
int validIndex;
|
|
|
|
Assert(VARATT_IS_EXTERNAL_ONDISK(attr));
|
|
|
|
/* Must copy to access aligned fields */
|
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
|
|
|
|
/*
|
|
* It's nonsense to fetch slices of a compressed datum -- this isn't lo_*
|
|
* we can't return a compressed datum which is meaningful to toast later
|
|
*/
|
|
Assert(!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer));
|
|
|
|
attrsize = toast_pointer.va_extsize;
|
|
totalchunks = ((attrsize - 1) / TOAST_MAX_CHUNK_SIZE) + 1;
|
|
|
|
if (sliceoffset >= attrsize)
|
|
{
|
|
sliceoffset = 0;
|
|
length = 0;
|
|
}
|
|
|
|
if (((sliceoffset + length) > attrsize) || length < 0)
|
|
length = attrsize - sliceoffset;
|
|
|
|
result = (struct varlena *) palloc(length + VARHDRSZ);
|
|
|
|
if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
|
|
SET_VARSIZE_COMPRESSED(result, length + VARHDRSZ);
|
|
else
|
|
SET_VARSIZE(result, length + VARHDRSZ);
|
|
|
|
if (length == 0)
|
|
return result; /* Can save a lot of work at this point! */
|
|
|
|
startchunk = sliceoffset / TOAST_MAX_CHUNK_SIZE;
|
|
endchunk = (sliceoffset + length - 1) / TOAST_MAX_CHUNK_SIZE;
|
|
numchunks = (endchunk - startchunk) + 1;
|
|
|
|
startoffset = sliceoffset % TOAST_MAX_CHUNK_SIZE;
|
|
endoffset = (sliceoffset + length - 1) % TOAST_MAX_CHUNK_SIZE;
|
|
|
|
/*
|
|
* Open the toast relation and its indexes
|
|
*/
|
|
toastrel = heap_open(toast_pointer.va_toastrelid, AccessShareLock);
|
|
toasttupDesc = toastrel->rd_att;
|
|
|
|
/* Look for the valid index of toast relation */
|
|
validIndex = toast_open_indexes(toastrel,
|
|
AccessShareLock,
|
|
&toastidxs,
|
|
&num_indexes);
|
|
|
|
/*
|
|
* Setup a scan key to fetch from the index. This is either two keys or
|
|
* three depending on the number of chunks.
|
|
*/
|
|
ScanKeyInit(&toastkey[0],
|
|
(AttrNumber) 1,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(toast_pointer.va_valueid));
|
|
|
|
/*
|
|
* Use equality condition for one chunk, a range condition otherwise:
|
|
*/
|
|
if (numchunks == 1)
|
|
{
|
|
ScanKeyInit(&toastkey[1],
|
|
(AttrNumber) 2,
|
|
BTEqualStrategyNumber, F_INT4EQ,
|
|
Int32GetDatum(startchunk));
|
|
nscankeys = 2;
|
|
}
|
|
else
|
|
{
|
|
ScanKeyInit(&toastkey[1],
|
|
(AttrNumber) 2,
|
|
BTGreaterEqualStrategyNumber, F_INT4GE,
|
|
Int32GetDatum(startchunk));
|
|
ScanKeyInit(&toastkey[2],
|
|
(AttrNumber) 2,
|
|
BTLessEqualStrategyNumber, F_INT4LE,
|
|
Int32GetDatum(endchunk));
|
|
nscankeys = 3;
|
|
}
|
|
|
|
/*
|
|
* Read the chunks by index
|
|
*
|
|
* The index is on (valueid, chunkidx) so they will come in order
|
|
*/
|
|
nextidx = startchunk;
|
|
toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex],
|
|
SnapshotToast, nscankeys, toastkey);
|
|
while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL)
|
|
{
|
|
/*
|
|
* Have a chunk, extract the sequence number and the data
|
|
*/
|
|
residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull));
|
|
Assert(!isnull);
|
|
chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull));
|
|
Assert(!isnull);
|
|
if (!VARATT_IS_EXTENDED(chunk))
|
|
{
|
|
chunksize = VARSIZE(chunk) - VARHDRSZ;
|
|
chunkdata = VARDATA(chunk);
|
|
}
|
|
else if (VARATT_IS_SHORT(chunk))
|
|
{
|
|
/* could happen due to heap_form_tuple doing its thing */
|
|
chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT;
|
|
chunkdata = VARDATA_SHORT(chunk);
|
|
}
|
|
else
|
|
{
|
|
/* should never happen */
|
|
elog(ERROR, "found toasted toast chunk for toast value %u in %s",
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
chunksize = 0; /* keep compiler quiet */
|
|
chunkdata = NULL;
|
|
}
|
|
|
|
/*
|
|
* Some checks on the data we've found
|
|
*/
|
|
if ((residx != nextidx) || (residx > endchunk) || (residx < startchunk))
|
|
elog(ERROR, "unexpected chunk number %d (expected %d) for toast value %u in %s",
|
|
residx, nextidx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
if (residx < totalchunks - 1)
|
|
{
|
|
if (chunksize != TOAST_MAX_CHUNK_SIZE)
|
|
elog(ERROR, "unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s when fetching slice",
|
|
chunksize, (int) TOAST_MAX_CHUNK_SIZE,
|
|
residx, totalchunks,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
}
|
|
else if (residx == totalchunks - 1)
|
|
{
|
|
if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != attrsize)
|
|
elog(ERROR, "unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s when fetching slice",
|
|
chunksize,
|
|
(int) (attrsize - residx * TOAST_MAX_CHUNK_SIZE),
|
|
residx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
}
|
|
else
|
|
elog(ERROR, "unexpected chunk number %d (out of range %d..%d) for toast value %u in %s",
|
|
residx,
|
|
0, totalchunks - 1,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
|
|
/*
|
|
* Copy the data into proper place in our result
|
|
*/
|
|
chcpystrt = 0;
|
|
chcpyend = chunksize - 1;
|
|
if (residx == startchunk)
|
|
chcpystrt = startoffset;
|
|
if (residx == endchunk)
|
|
chcpyend = endoffset;
|
|
|
|
memcpy(VARDATA(result) +
|
|
(residx * TOAST_MAX_CHUNK_SIZE - sliceoffset) + chcpystrt,
|
|
chunkdata + chcpystrt,
|
|
(chcpyend - chcpystrt) + 1);
|
|
|
|
nextidx++;
|
|
}
|
|
|
|
/*
|
|
* Final checks that we successfully fetched the datum
|
|
*/
|
|
if (nextidx != (endchunk + 1))
|
|
elog(ERROR, "missing chunk number %d for toast value %u in %s",
|
|
nextidx,
|
|
toast_pointer.va_valueid,
|
|
RelationGetRelationName(toastrel));
|
|
|
|
/*
|
|
* End scan and close relations
|
|
*/
|
|
systable_endscan_ordered(toastscan);
|
|
toast_close_indexes(toastidxs, num_indexes, AccessShareLock);
|
|
heap_close(toastrel, AccessShareLock);
|
|
|
|
return result;
|
|
}
|
|
|
|
/* ----------
|
|
* toast_open_indexes
|
|
*
|
|
* Get an array of the indexes associated to the given toast relation
|
|
* and return as well the position of the valid index used by the toast
|
|
* relation in this array. It is the responsibility of the caller of this
|
|
* function to close the indexes as well as free them.
|
|
*/
|
|
static int
|
|
toast_open_indexes(Relation toastrel,
|
|
LOCKMODE lock,
|
|
Relation **toastidxs,
|
|
int *num_indexes)
|
|
{
|
|
int i = 0;
|
|
int res = 0;
|
|
bool found = false;
|
|
List *indexlist;
|
|
ListCell *lc;
|
|
|
|
/* Get index list of the toast relation */
|
|
indexlist = RelationGetIndexList(toastrel);
|
|
Assert(indexlist != NIL);
|
|
|
|
*num_indexes = list_length(indexlist);
|
|
|
|
/* Open all the index relations */
|
|
*toastidxs = (Relation *) palloc(*num_indexes * sizeof(Relation));
|
|
foreach(lc, indexlist)
|
|
(*toastidxs)[i++] = index_open(lfirst_oid(lc), lock);
|
|
|
|
/* Fetch the first valid index in list */
|
|
for (i = 0; i < *num_indexes; i++)
|
|
{
|
|
Relation toastidx = (*toastidxs)[i];
|
|
|
|
if (toastidx->rd_index->indisvalid)
|
|
{
|
|
res = i;
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Free index list, not necessary anymore as relations are opened and a
|
|
* valid index has been found.
|
|
*/
|
|
list_free(indexlist);
|
|
|
|
/*
|
|
* The toast relation should have one valid index, so something is going
|
|
* wrong if there is nothing.
|
|
*/
|
|
if (!found)
|
|
elog(ERROR, "no valid index found for toast relation with Oid %u",
|
|
RelationGetRelid(toastrel));
|
|
|
|
return res;
|
|
}
|
|
|
|
/* ----------
|
|
* toast_close_indexes
|
|
*
|
|
* Close an array of indexes for a toast relation and free it. This should
|
|
* be called for a set of indexes opened previously with toast_open_indexes.
|
|
*/
|
|
static void
|
|
toast_close_indexes(Relation *toastidxs, int num_indexes, LOCKMODE lock)
|
|
{
|
|
int i;
|
|
|
|
/* Close relations and clean up things */
|
|
for (i = 0; i < num_indexes; i++)
|
|
index_close(toastidxs[i], lock);
|
|
pfree(toastidxs);
|
|
}
|