*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.76 2000/10/08 03:53:14 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.77 2000/10/21 15:55:24 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/genam.h"
#include "access/heapam.h"
#include "access/nbtree.h"
+#include "access/htup.h"
#include "catalog/catalog.h"
+#include "catalog/catname.h"
#include "catalog/heap.h"
#include "catalog/index.h"
+#include "catalog/indexing.h"
#include "catalog/pg_opclass.h"
+#include "catalog/pg_largeobject.h"
#include "catalog/pg_type.h"
#include "libpq/libpq-fs.h"
#include "miscadmin.h"
#include "storage/large_object.h"
#include "storage/smgr.h"
#include "utils/fmgroids.h"
-#include "utils/relcache.h"
+#include "utils/builtins.h"
-/*
- * Warning, Will Robinson... In order to pack data into an inversion
- * file as densely as possible, we violate the class abstraction here.
- * When we're appending a new tuple to the end of the table, we check
- * the last page to see how much data we can put on it. If it's more
- * than IMINBLK, we write enough to fill the page. This limits external
- * fragmentation. In no case can we write more than IMAXBLK, since
- * the 8K postgres page size less overhead leaves only this much space
- * for data.
- */
+#include <errno.h>
-/*
- * In order to prevent buffer leak on transaction commit, large object
- * scan index handling has been modified. Indexes are persistant inside
- * a transaction but may be closed between two calls to this API (when
- * transaction is committed while object is opened, or when no
- * transaction is active). Scan indexes are thus now reinitialized using
- * the object current offset. [PA]
- *
- * Some cleanup has been also done for non freed memory.
- *
- * For subsequent notes, [PA] is Pascal André <andre@via.ecp.fr>
- */
+#define IBLKSIZE (MaxTupleSize - MinHeapTupleBitmapSize - sizeof(int32) * 3)
-#define IFREESPC(p) (PageGetFreeSpace(p) - \
- MAXALIGN(offsetof(HeapTupleHeaderData,t_bits)) - \
- MAXALIGN(sizeof(struct varlena) + sizeof(int32)) - \
- sizeof(double))
-#define IMAXBLK 8092
-#define IMINBLK 512
-
-/* non-export function prototypes */
-static HeapTuple inv_newtuple(LargeObjectDesc *obj_desc, Buffer buffer,
- Page page, char *dbuf, int nwrite);
-static void inv_fetchtup(LargeObjectDesc *obj_desc, HeapTuple tuple, Buffer *buffer);
-static int inv_wrnew(LargeObjectDesc *obj_desc, char *buf, int nbytes);
-static int inv_wrold(LargeObjectDesc *obj_desc, char *dbuf, int nbytes,
- HeapTuple tuple, Buffer buffer);
-static void inv_indextup(LargeObjectDesc *obj_desc, HeapTuple tuple);
-static int _inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln);
+/* Defined in backend/storage/catalog/large_object.c */
+bytea *_byteain(const char *data, int32 size);
+
+static int32 getbytealen(bytea *data) {
+ if (VARSIZE(data) < VARHDRSZ)
+ elog(ERROR, "getbytealen: VARSIZE(data) < VARHDRSZ. This is internal error.");
+ return (VARSIZE(data) - VARHDRSZ);
+}
/*
* inv_create -- create a new large object.
* Returns:
* large object descriptor, appropriately filled in.
*/
+
LargeObjectDesc *
inv_create(int flags)
{
+ int file_oid;
LargeObjectDesc *retval;
- Oid file_oid;
- Relation r;
- Relation indr;
- TupleDesc tupdesc;
- IndexInfo *indexInfo;
- Oid classObjectId[1];
- char objname[NAMEDATALEN];
- char indname[NAMEDATALEN];
-
+
/*
* add one here since the pg_class tuple created will have the next
* oid and we want to have the relation name to correspond to the
*/
file_oid = newoid() + 1;
- /* come up with some table names */
- sprintf(objname, "xinv%u", file_oid);
- sprintf(indname, "xinx%u", file_oid);
-
- if (RelnameFindRelid(objname) != InvalidOid)
- elog(ERROR,
- "internal error: %s already exists -- cannot create large obj",
- objname);
- if (RelnameFindRelid(indname) != InvalidOid)
- elog(ERROR,
- "internal error: %s already exists -- cannot create large obj",
- indname);
-
- /* this is pretty painful... want a tuple descriptor */
- tupdesc = CreateTemplateTupleDesc(2);
- TupleDescInitEntry(tupdesc, (AttrNumber) 1,
- "olastbye",
- INT4OID,
- -1, 0, false);
- TupleDescInitEntry(tupdesc, (AttrNumber) 2,
- "odata",
- BYTEAOID,
- -1, 0, false);
-
- /*
- * First create the table to hold the inversion large object. It will
- * be located on whatever storage manager the user requested.
- */
-
- heap_create_with_catalog(objname, tupdesc, RELKIND_LOBJECT,
- false, false);
-
- /* make the relation visible in this transaction */
- CommandCounterIncrement();
-
- /*--------------------
- * We hold AccessShareLock on any large object we have open
- * by inv_create or inv_open; it is released by inv_close.
- * Note this will not conflict with ExclusiveLock or ShareLock
- * that we acquire when actually reading/writing; it just prevents
- * deletion of the large object while we have it open.
- *--------------------
- */
- r = heap_openr(objname, AccessShareLock);
-
- /*
- * Now create a btree index on the relation's olastbyte attribute to
- * make seeks go faster.
- */
- indexInfo = makeNode(IndexInfo);
- indexInfo->ii_NumIndexAttrs = 1;
- indexInfo->ii_NumKeyAttrs = 1;
- indexInfo->ii_KeyAttrNumbers[0] = 1;
- indexInfo->ii_Predicate = NULL;
- indexInfo->ii_FuncOid = InvalidOid;
- indexInfo->ii_Unique = false;
-
- classObjectId[0] = INT4_OPS_OID;
-
- index_create(objname, indname, indexInfo,
- BTREE_AM_OID, classObjectId,
- false, false, false);
-
- /* make the index visible in this transaction */
- CommandCounterIncrement();
-
- indr = index_openr(indname);
-
- if (!RelationIsValid(indr))
- {
- elog(ERROR, "cannot create index for large obj on %s under inversion",
- DatumGetCString(DirectFunctionCall1(smgrout,
- Int16GetDatum(DEFAULT_SMGR))));
- }
+ if (LargeobjectFind(file_oid) == 1)
+ elog(ERROR, "inv_create: large object %d already exists. This is internal error.", file_oid);
retval = (LargeObjectDesc *) palloc(sizeof(LargeObjectDesc));
- retval->heap_r = r;
- retval->index_r = indr;
- retval->iscan = (IndexScanDesc) NULL;
- retval->hdesc = RelationGetDescr(r);
- retval->idesc = RelationGetDescr(indr);
- retval->offset = retval->lowbyte = retval->highbyte = 0;
- ItemPointerSetInvalid(&(retval->htid));
- retval->flags = 0;
-
- if (flags & INV_WRITE)
- {
- LockRelation(r, ExclusiveLock);
+ if (flags & INV_WRITE) {
retval->flags = IFS_WRLOCK | IFS_RDLOCK;
- }
- else if (flags & INV_READ)
- {
- LockRelation(r, ShareLock);
+ retval->heap_r = heap_openr(LargeobjectRelationName, RowExclusiveLock);
+ } else if (flags & INV_READ) {
retval->flags = IFS_RDLOCK;
- }
- retval->flags |= IFS_ATEOF; /* since we know the object is empty */
-
+ retval->heap_r = heap_openr(LargeobjectRelationName, AccessShareLock);
+ } else
+ elog(ERROR, "inv_create: invalid flags: %d", flags);
+
+ retval->flags |= IFS_ATEOF;
+ retval->index_r = index_openr(LargeobjectLOIdPNIndex);
+ retval->offset = 0;
+ retval->id = file_oid;
+ (void)LargeobjectCreate(file_oid);
return retval;
}
inv_open(Oid lobjId, int flags)
{
LargeObjectDesc *retval;
- Relation r;
- char *indname;
- Relation indrel;
-
- r = heap_open(lobjId, AccessShareLock);
- indname = pstrdup(RelationGetRelationName(r));
-
- /*
- * hack hack hack... we know that the fourth character of the
- * relation name is a 'v', and that the fourth character of the index
- * name is an 'x', and that they're otherwise identical.
- */
- indname[3] = 'x';
- indrel = index_openr(indname);
+ if (LargeobjectFind(lobjId) == 0)
+ elog(ERROR, "inv_open: large object %d not found", lobjId);
+
+ retval = (LargeObjectDesc *)palloc(sizeof(LargeObjectDesc));
- if (!RelationIsValid(indrel))
- return (LargeObjectDesc *) NULL;
-
- retval = (LargeObjectDesc *) palloc(sizeof(LargeObjectDesc));
-
- retval->heap_r = r;
- retval->index_r = indrel;
- retval->iscan = (IndexScanDesc) NULL;
- retval->hdesc = RelationGetDescr(r);
- retval->idesc = RelationGetDescr(indrel);
- retval->offset = retval->lowbyte = retval->highbyte = 0;
- ItemPointerSetInvalid(&(retval->htid));
- retval->flags = 0;
-
- if (flags & INV_WRITE)
- {
- LockRelation(r, ExclusiveLock);
+ if (flags & INV_WRITE) {
retval->flags = IFS_WRLOCK | IFS_RDLOCK;
- }
- else if (flags & INV_READ)
- {
- LockRelation(r, ShareLock);
+ retval->heap_r = heap_openr(LargeobjectRelationName, RowExclusiveLock);
+ } else if (flags & INV_READ) {
retval->flags = IFS_RDLOCK;
- }
+ retval->heap_r = heap_openr(LargeobjectRelationName, AccessShareLock);
+ } else
+ elog(ERROR, "inv_open: invalid flags: %d", flags);
+
+ retval->index_r = index_openr(LargeobjectLOIdPNIndex);
+ retval->offset = 0;
+ retval->id = lobjId;
return retval;
}
{
Assert(PointerIsValid(obj_desc));
- if (obj_desc->iscan != (IndexScanDesc) NULL)
- {
- index_endscan(obj_desc->iscan);
- obj_desc->iscan = NULL;
- }
-
+ if (obj_desc->flags & IFS_WRLOCK)
+ heap_close(obj_desc->heap_r, RowExclusiveLock);
+ else if (obj_desc->flags & IFS_RDLOCK)
+ heap_close(obj_desc->heap_r, AccessShareLock);
index_close(obj_desc->index_r);
- heap_close(obj_desc->heap_r, AccessShareLock);
-
pfree(obj_desc);
}
int
inv_drop(Oid lobjId)
{
- Relation r;
-
- r = RelationIdGetRelation(lobjId);
- if (!RelationIsValid(r))
- return -1;
-
- if (r->rd_rel->relkind != RELKIND_LOBJECT)
- {
- /* drop relcache refcount from RelationIdGetRelation */
- RelationDecrementReferenceCount(r);
- return -1;
- }
-
- /*
- * Since heap_drop_with_catalog will destroy the relcache entry,
- * there's no need to drop the refcount in this path.
- */
- heap_drop_with_catalog(RelationGetRelationName(r), false);
+ LargeobjectDrop(lobjId);
return 1;
}
#endif
-int
-inv_seek(LargeObjectDesc *obj_desc, int offset, int whence)
-{
- int oldOffset;
- Datum d;
- ScanKeyData skey;
+static uint32 inv_getsize(LargeObjectDesc *obj_desc) {
+ uint32 found = 0;
+ uint32 lastbyte = 0;
+ ScanKeyData skey;
+ IndexScanDesc sd = (IndexScanDesc) NULL;
+ RetrieveIndexResult indexRes;
+ HeapTupleData tuple;
+ Buffer buffer;
+ Form_pg_largeobject data;
Assert(PointerIsValid(obj_desc));
- if (whence == SEEK_CUR)
- {
- offset += obj_desc->offset; /* calculate absolute position */
- }
- else if (whence == SEEK_END)
- {
- /* need read lock for getsize */
- if (!(obj_desc->flags & IFS_RDLOCK))
- {
- LockRelation(obj_desc->heap_r, ShareLock);
- obj_desc->flags |= IFS_RDLOCK;
- }
- offset += _inv_getsize(obj_desc->heap_r,
- obj_desc->hdesc,
- obj_desc->index_r);
+ ScanKeyEntryInitialize(&skey,
+ (bits16) 0x0,
+ (AttrNumber) 1,
+ (RegProcedure) F_OIDEQ,
+ ObjectIdGetDatum(obj_desc->id));
+
+ sd = index_beginscan(obj_desc->index_r, true, 1, &skey);
+ tuple.t_datamcxt = CurrentMemoryContext;
+ tuple.t_data = NULL;
+ while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+ tuple.t_self = indexRes->heap_iptr;
+ heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+ pfree(indexRes);
+ if (tuple.t_data == NULL)
+ continue;
+ found++;
+ data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+ lastbyte = data->pageno * IBLKSIZE + getbytealen(&(data->data));
+ ReleaseBuffer(buffer);
+ break;
}
- /* now we can assume that the operation is SEEK_SET */
-
- /*
- * Whenever we do a seek, we turn off the EOF flag bit to force
- * ourselves to check for real on the next read.
- */
-
- obj_desc->flags &= ~IFS_ATEOF;
- oldOffset = obj_desc->offset;
- obj_desc->offset = offset;
+
+ index_endscan(sd);
- /* try to avoid doing any work, if we can manage it */
- if (offset >= obj_desc->lowbyte
- && offset <= obj_desc->highbyte
- && oldOffset <= obj_desc->highbyte
- && obj_desc->iscan != (IndexScanDesc) NULL)
- return offset;
+ if (found == 0)
+ elog(ERROR, "inv_getsize: large object %d not found", obj_desc->id);
+ return lastbyte;
+}
- /*
- * To do a seek on an inversion file, we start an index scan that will
- * bring us to the right place. Each tuple in an inversion file
- * stores the offset of the last byte that appears on it, and we have
- * an index on this.
- */
- if (obj_desc->iscan != (IndexScanDesc) NULL)
- {
- d = Int32GetDatum(offset);
- btmovescan(obj_desc->iscan, d);
- }
- else
- {
- ScanKeyEntryInitialize(&skey, 0x0, 1, F_INT4GE,
- Int32GetDatum(offset));
+int
+inv_seek(LargeObjectDesc *obj_desc, int offset, int whence)
+{
+ Assert(PointerIsValid(obj_desc));
- obj_desc->iscan = index_beginscan(obj_desc->index_r,
- (bool) 0, (uint16) 1,
- &skey);
+ switch (whence) {
+ case SEEK_SET:
+ if (offset < 0)
+ elog(ERROR, "inv_seek: invalid offset: %d", offset);
+ obj_desc->offset = offset;
+ break;
+ case SEEK_CUR:
+ if ((obj_desc->offset + offset) < 0)
+ elog(ERROR, "inv_seek: invalid offset: %d", offset);
+ obj_desc->offset += offset;
+ break;
+ case SEEK_END:
+ {
+ int4 size = inv_getsize(obj_desc);
+ if (offset > size)
+ elog(ERROR, "inv_seek: invalid offset");
+ obj_desc->offset = size - offset;
+ }
+ break;
+ default:
+ elog(ERROR, "inv_seek: invalid whence: %d", whence);
}
-
- return offset;
+ return obj_desc->offset;
}
int
int
inv_read(LargeObjectDesc *obj_desc, char *buf, int nbytes)
{
- HeapTupleData tuple;
- int nread;
- int off;
- int ncopy;
- Datum d;
- struct varlena *fsblock;
- bool isNull;
+ uint32 nread = 0;
+ uint32 n;
+ uint32 off;
+ uint32 len;
+ uint32 found = 0;
+ uint32 pageno = obj_desc->offset / IBLKSIZE;
+ ScanKeyData skey[2];
+ IndexScanDesc sd = (IndexScanDesc) NULL;
+ RetrieveIndexResult indexRes;
+ HeapTupleData tuple;
+ Buffer buffer;
+ Form_pg_largeobject data;
Assert(PointerIsValid(obj_desc));
Assert(buf != NULL);
- /* if we're already at EOF, we don't need to do any work here */
- if (obj_desc->flags & IFS_ATEOF)
- return 0;
-
- /* make sure we obey two-phase locking */
- if (!(obj_desc->flags & IFS_RDLOCK))
- {
- LockRelation(obj_desc->heap_r, ShareLock);
- obj_desc->flags |= IFS_RDLOCK;
- }
-
- nread = 0;
-
- /* fetch a block at a time */
- while (nread < nbytes)
- {
- Buffer buffer;
-
- /* fetch an inversion file system block */
- inv_fetchtup(obj_desc, &tuple, &buffer);
+ ScanKeyEntryInitialize(&skey[0],
+ (bits16) 0x0,
+ (AttrNumber) 1,
+ (RegProcedure) F_OIDEQ,
+ ObjectIdGetDatum(obj_desc->id));
+
+ ScanKeyEntryInitialize(&skey[1],
+ (bits16) 0x0,
+ (AttrNumber) 2,
+ (RegProcedure) F_INT4GE,
+ Int32GetDatum(pageno));
+
+ sd = index_beginscan(obj_desc->index_r, false, 2, skey);
+ tuple.t_datamcxt = CurrentMemoryContext;
+ tuple.t_data = NULL;
+ while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+ tuple.t_self = indexRes->heap_iptr;
+ heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+ pfree(indexRes);
if (tuple.t_data == NULL)
- {
- obj_desc->flags |= IFS_ATEOF;
- break;
+ continue;
+
+ found++;
+ data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+ if (data->pageno != pageno) {
+ ReleaseBuffer(buffer);
+ index_endscan(sd);
+ return 0;
}
- /* copy the data from this block into the buffer */
- d = heap_getattr(&tuple, 2, obj_desc->hdesc, &isNull);
- fsblock = (struct varlena *) DatumGetPointer(d);
- ReleaseBuffer(buffer);
-
- /*
- * If block starts beyond current seek point, then we are looking
- * at a "hole" (unwritten area) in the object. Return zeroes for
- * the "hole".
- */
- if (obj_desc->offset < obj_desc->lowbyte)
- {
- int nzeroes = obj_desc->lowbyte - obj_desc->offset;
-
- if (nzeroes > (nbytes - nread))
- nzeroes = (nbytes - nread);
- MemSet(buf, 0, nzeroes);
- buf += nzeroes;
- nread += nzeroes;
- obj_desc->offset += nzeroes;
- if (nread >= nbytes)
- break;
+ len = getbytealen(&(data->data));
+ off = obj_desc->offset % IBLKSIZE;
+ if (off == len) {
+ ReleaseBuffer(buffer);
+ break;
}
+ if (off > len) {
+ ReleaseBuffer(buffer);
+ index_endscan(sd);
+ return 0;
+ }
+ n = len - off;
- off = obj_desc->offset - obj_desc->lowbyte;
- ncopy = obj_desc->highbyte - obj_desc->offset + 1;
- if (ncopy > (nbytes - nread))
- ncopy = (nbytes - nread);
- memmove(buf, &(fsblock->vl_dat[off]), ncopy);
+ n = (n < (nbytes - nread)) ? n : (nbytes - nread);
+ memcpy(buf + nread, VARDATA(&(data->data)) + off, n);
+ nread += n;
+ obj_desc->offset += n;
- /* move pointers past the amount we just read */
- buf += ncopy;
- nread += ncopy;
- obj_desc->offset += ncopy;
+ ReleaseBuffer(buffer);
+ pageno++;
+ if (nread == nbytes)
+ break;
}
+ index_endscan(sd);
+
+ if (found == 0)
+ return 0;
+
return nread;
}
-int
-inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes)
-{
- HeapTupleData tuple;
- int nwritten;
- int tuplen;
+static int inv_write_existing(LargeObjectDesc *obj_desc, char *buf, int nbytes, int *found) {
+ uint32 n = 0;
+ uint32 off;
+ uint32 len;
+ int i;
+ HeapTupleData tuple;
+ HeapTuple newtup;
+ Buffer buffer;
+ Form_pg_largeobject data;
+ ScanKeyData skey[2];
+ IndexScanDesc sd = (IndexScanDesc) NULL;
+ RetrieveIndexResult indexRes;
+ Relation idescs[Num_pg_largeobject_indices];
+ Datum values[Natts_pg_largeobject];
+ char nulls[Natts_pg_largeobject];
+ char replace[Natts_pg_largeobject];
Assert(PointerIsValid(obj_desc));
Assert(buf != NULL);
- /*
- * Make sure we obey two-phase locking. A write lock entitles you to
- * read the relation, as well.
- */
-
- if (!(obj_desc->flags & IFS_WRLOCK))
- {
- LockRelation(obj_desc->heap_r, ExclusiveLock);
- obj_desc->flags |= (IFS_WRLOCK | IFS_RDLOCK);
- }
-
- nwritten = 0;
-
- /* write a block at a time */
- while (nwritten < nbytes)
- {
- Buffer buffer;
-
- /*
- * Fetch the current inversion file system block. We can skip
- * the work if we already know we are at EOF.
- */
-
- if (obj_desc->flags & IFS_ATEOF)
- tuple.t_data = NULL;
- else
- inv_fetchtup(obj_desc, &tuple, &buffer);
-
- /* either append or replace a block, as required */
- if (tuple.t_data == NULL)
- tuplen = inv_wrnew(obj_desc, buf, nbytes - nwritten);
- else
- {
- if (obj_desc->offset > obj_desc->highbyte)
- {
- tuplen = inv_wrnew(obj_desc, buf, nbytes - nwritten);
- ReleaseBuffer(buffer);
- }
- else
- tuplen = inv_wrold(obj_desc, buf, nbytes - nwritten, &tuple, buffer);
+ ScanKeyEntryInitialize(&skey[0],
+ (bits16) 0,
+ (AttrNumber) 1,
+ (RegProcedure) F_OIDEQ,
+ ObjectIdGetDatum(obj_desc->id));
- /*
- * inv_wrold() has already issued WriteBuffer() which has
- * decremented local reference counter (LocalRefCount). So we
- * should not call ReleaseBuffer() here. -- Tatsuo 99/2/4
- */
- }
+ ScanKeyEntryInitialize(&skey[1],
+ (bits16) 0x0,
+ (AttrNumber) 2,
+ (RegProcedure) F_INT4EQ,
+ Int32GetDatum(obj_desc->offset / IBLKSIZE));
- /* move pointers past the amount we just wrote */
- buf += tuplen;
- nwritten += tuplen;
- obj_desc->offset += tuplen;
+ CommandCounterIncrement();
+ sd = index_beginscan(obj_desc->index_r, false, 2, skey);
+ tuple.t_datamcxt = CurrentMemoryContext;
+ tuple.t_data = NULL;
+ while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+ tuple.t_self = indexRes->heap_iptr;
+ heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+ pfree(indexRes);
+ if (tuple.t_data != NULL)
+ break;
}
- /* that's it */
- return nwritten;
-}
-
-/*
- * inv_cleanindex
- * Clean opened indexes for large objects, and clears current result.
- * This is necessary on transaction commit in order to prevent buffer
- * leak.
- * This function must be called for each opened large object.
- * [ PA, 7/17/98 ]
- */
-void
-inv_cleanindex(LargeObjectDesc *obj_desc)
-{
- Assert(PointerIsValid(obj_desc));
-
- if (obj_desc->iscan == (IndexScanDesc) NULL)
- return;
-
- index_endscan(obj_desc->iscan);
- obj_desc->iscan = (IndexScanDesc) NULL;
-
- ItemPointerSetInvalid(&(obj_desc->htid));
-}
-
-/*
- * inv_fetchtup -- Fetch an inversion file system block.
- *
- * This routine finds the file system block containing the offset
- * recorded in the obj_desc structure. Later, we need to think about
- * the effects of non-functional updates (can you rewrite the same
- * block twice in a single transaction?), but for now, we won't bother.
- *
- * Parameters:
- * obj_desc -- the object descriptor.
- * bufP -- pointer to a buffer in the buffer cache; caller
- * must free this.
- *
- * Returns:
- * A heap tuple containing the desired block, or NULL if no
- * such tuple exists.
- */
-static void
-inv_fetchtup(LargeObjectDesc *obj_desc, HeapTuple tuple, Buffer *buffer)
-{
- RetrieveIndexResult res;
- Datum d;
- int firstbyte,
- lastbyte;
- struct varlena *fsblock;
- bool isNull;
-
- /*
- * If we've exhausted the current block, we need to get the next one.
- * When we support time travel and non-functional updates, we will
- * need to loop over the blocks, rather than just have an 'if', in
- * order to find the one we're really interested in.
- */
-
- if (obj_desc->offset > obj_desc->highbyte
- || obj_desc->offset < obj_desc->lowbyte
- || !ItemPointerIsValid(&(obj_desc->htid)))
- {
- ScanKeyData skey;
-
- ScanKeyEntryInitialize(&skey, 0x0, 1, F_INT4GE,
- Int32GetDatum(obj_desc->offset));
-
- /* initialize scan key if not done */
- if (obj_desc->iscan == (IndexScanDesc) NULL)
- {
-
- /*
- * As scan index may be prematurely closed (on commit), we
- * must use object current offset (was 0) to reinitialize the
- * entry [ PA ].
- */
- obj_desc->iscan = index_beginscan(obj_desc->index_r,
- (bool) 0, (uint16) 1,
- &skey);
- }
- else
- index_rescan(obj_desc->iscan, false, &skey);
-
- do
- {
- res = index_getnext(obj_desc->iscan, ForwardScanDirection);
-
- if (res == (RetrieveIndexResult) NULL)
- {
- ItemPointerSetInvalid(&(obj_desc->htid));
- tuple->t_datamcxt = NULL;
- tuple->t_data = NULL;
- return;
- }
+ index_endscan(sd);
+ if (tuple.t_data == NULL)
+ return 0;
+
+ (*found)++;
+ data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+ off = obj_desc->offset % IBLKSIZE;
+ len = getbytealen(&(data->data));
- /*
- * For time travel, we need to use the actual time qual here,
- * rather that NowTimeQual. We currently have no way to pass
- * a time qual in.
- *
- * This is now valid for snapshot !!! And should be fixed in some
- * way... - vadim 07/28/98
- *
- */
- tuple->t_self = res->heap_iptr;
- heap_fetch(obj_desc->heap_r, SnapshotNow, tuple, buffer);
- pfree(res);
- } while (tuple->t_data == NULL);
-
- /* remember this tid -- we may need it for later reads/writes */
- ItemPointerCopy(&(tuple->t_self), &obj_desc->htid);
- }
- else
- {
- tuple->t_self = obj_desc->htid;
- heap_fetch(obj_desc->heap_r, SnapshotNow, tuple, buffer);
- if (tuple->t_data == NULL)
- elog(ERROR, "inv_fetchtup: heap_fetch failed");
+ if (len > IBLKSIZE) {
+ ReleaseBuffer(buffer);
+ elog(FATAL, "Internal error: len > IBLKSIZE");
}
- /*
- * By here, we have the heap tuple we're interested in. We cache the
- * upper and lower bounds for this block in the object descriptor and
- * return the tuple.
- */
-
- d = heap_getattr(tuple, 1, obj_desc->hdesc, &isNull);
- lastbyte = (int32) DatumGetInt32(d);
- d = heap_getattr(tuple, 2, obj_desc->hdesc, &isNull);
- fsblock = (struct varlena *) DatumGetPointer(d);
-
- /*
- * order of + and - is important -- these are unsigned quantites near
- * 0
- */
- firstbyte = (lastbyte + 1 + sizeof(fsblock->vl_len)) - fsblock->vl_len;
-
- obj_desc->lowbyte = firstbyte;
- obj_desc->highbyte = lastbyte;
-
- return;
-}
-
-/*
- * inv_wrnew() -- append a new filesystem block tuple to the inversion
- * file.
- *
- * In response to an inv_write, we append one or more file system
- * blocks to the class containing the large object. We violate the
- * class abstraction here in order to pack things as densely as we
- * are able. We examine the last page in the relation, and write
- * just enough to fill it, assuming that it has above a certain
- * threshold of space available. If the space available is less than
- * the threshold, we allocate a new page by writing a big tuple.
- *
- * By the time we get here, we know all the parameters passed in
- * are valid, and that we hold the appropriate lock on the heap
- * relation.
- *
- * Parameters:
- * obj_desc: large object descriptor for which to append block.
- * buf: buffer containing data to write.
- * nbytes: amount to write
- *
- * Returns:
- * number of bytes actually written to the new tuple.
- */
-static int
-inv_wrnew(LargeObjectDesc *obj_desc, char *buf, int nbytes)
-{
- Relation hr;
- HeapTuple ntup;
- Buffer buffer;
- Page page;
- int nblocks;
- int nwritten;
-
- hr = obj_desc->heap_r;
-
- /*
- * Get the last block in the relation. If there's no data in the
- * relation at all, then we just get a new block. Otherwise, we check
- * the last block to see whether it has room to accept some or all of
- * the data that the user wants to write. If it doesn't, then we
- * allocate a new block.
- */
-
- nblocks = RelationGetNumberOfBlocks(hr);
-
- if (nblocks > 0)
- {
- buffer = ReadBuffer(hr, nblocks - 1);
- page = BufferGetPage(buffer);
+ for (i=0; i<Natts_pg_largeobject; i++) {
+ nulls[i] = ' ';
+ replace[i] = ' ';
+ values[i] = (Datum)NULL;
}
- else
- {
- buffer = ReadBuffer(hr, P_NEW);
- page = BufferGetPage(buffer);
- PageInit(page, BufferGetPageSize(buffer), 0);
- }
-
- /*
- * If the last page is too small to hold all the data, and it's too
- * small to hold IMINBLK, then we allocate a new page. If it will
- * hold at least IMINBLK, but less than all the data requested, then
- * we write IMINBLK here. The caller is responsible for noticing that
- * less than the requested number of bytes were written, and calling
- * this routine again.
- */
- nwritten = IFREESPC(page);
- if (nwritten < nbytes)
+ i = 0;
{
- if (nwritten < IMINBLK)
- {
- ReleaseBuffer(buffer);
- buffer = ReadBuffer(hr, P_NEW);
- page = BufferGetPage(buffer);
- PageInit(page, BufferGetPageSize(buffer), 0);
- if (nbytes > IMAXBLK)
- nwritten = IMAXBLK;
+ char b[IBLKSIZE];
+ int4 rest = len - off;
+
+ memset(b, 0, IBLKSIZE); /* Can optimize later */
+ if ((off > 0) && (len > 0)) /* We start in the middle of the tuple */
+ memcpy(b, VARDATA(&(data->data)), (off > len) ? len : off);
+
+ if ((nbytes <= rest) || (len == IBLKSIZE)) {
+ /* We will update inside existing tuple size */
+ if (nbytes < rest)
+ n = rest;
+ else
+ n = nbytes;
+ memcpy(b + off, buf, n);
+ if (n < rest) /* There's a rest of the tuple left */
+ memcpy(b + off + n, VARDATA(&(data->data)) + off + n, rest - n);
+ /* Update data only */
+ replace[2] = 'r';
+ values[2] = (Datum) _byteain(b, len);
+ } else {
+ /* We will extend tuple */
+ /* Do we fit into max tuple size */
+ if (nbytes <= (IBLKSIZE - off))
+ len = off + nbytes;
else
- nwritten = nbytes;
+ len = IBLKSIZE;
+ n = len - off;
+ memcpy(b + off, buf, n);
+ /* Update data */
+ replace[2] = 'r';
+ values[2] = (Datum) _byteain(b, len);
+ }
+
+ newtup = heap_modifytuple(&tuple, obj_desc->heap_r,
+ values, nulls, replace);
+
+ heap_update(obj_desc->heap_r, &newtup->t_self, newtup, NULL);
+ if (!IsIgnoringSystemIndexes()) {
+ CatalogOpenIndices(Num_pg_largeobject_indices, Name_pg_largeobject_indices, idescs);
+ CatalogIndexInsert(idescs, Num_pg_largeobject_indices, obj_desc->heap_r, newtup);
+ CatalogCloseIndices(Num_pg_largeobject_indices, idescs);
}
+ heap_freetuple(newtup);
}
- else
- nwritten = nbytes;
-
- /*
- * Insert a new file system block tuple, index it, and write it out.
- */
-
- ntup = inv_newtuple(obj_desc, buffer, page, buf, nwritten);
- inv_indextup(obj_desc, ntup);
- heap_freetuple(ntup);
-
- /* new tuple is inserted */
- WriteBuffer(buffer);
-
- return nwritten;
+ ReleaseBuffer(buffer);
+
+ return n;
}
-static int
-inv_wrold(LargeObjectDesc *obj_desc,
- char *dbuf,
- int nbytes,
- HeapTuple tuple,
- Buffer buffer)
-{
- Relation hr;
- HeapTuple ntup;
- Buffer newbuf;
- Page page;
- Page newpage;
- int tupbytes;
- Datum d;
- struct varlena *fsblock;
- int nwritten,
- nblocks,
- freespc;
- bool isNull;
- int keep_offset;
- RetrieveIndexResult res;
-
- /*
- * Since we're using a no-overwrite storage manager, the way we
- * overwrite blocks is to mark the old block invalid and append a new
- * block. First mark the old block invalid. This violates the tuple
- * abstraction.
- */
-
- TransactionIdStore(GetCurrentTransactionId(), &(tuple->t_data->t_xmax));
- tuple->t_data->t_cmax = GetCurrentCommandId();
- tuple->t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID);
-
- /*
- * If we're overwriting the entire block, we're lucky. All we need to
- * do is to insert a new block.
- */
-
- if (obj_desc->offset == obj_desc->lowbyte
- && obj_desc->lowbyte + nbytes >= obj_desc->highbyte)
- {
- WriteBuffer(buffer);
- return inv_wrnew(obj_desc, dbuf, nbytes);
- }
-
- /*
- * By here, we need to overwrite part of the data in the current
- * tuple. In order to reduce the degree to which we fragment blocks,
- * we guarantee that no block will be broken up due to an overwrite.
- * This means that we need to allocate a tuple on a new page, if
- * there's not room for the replacement on this one.
- */
-
- newbuf = buffer;
- page = BufferGetPage(buffer);
- newpage = BufferGetPage(newbuf);
- hr = obj_desc->heap_r;
- freespc = IFREESPC(page);
- d = heap_getattr(tuple, 2, obj_desc->hdesc, &isNull);
- fsblock = (struct varlena *) DatumGetPointer(d);
- tupbytes = fsblock->vl_len - sizeof(fsblock->vl_len);
-
- if (freespc < tupbytes)
- {
-
- /*
- * First see if there's enough space on the last page of the table
- * to put this tuple.
- */
-
- nblocks = RelationGetNumberOfBlocks(hr);
-
- if (nblocks > 0)
- {
- newbuf = ReadBuffer(hr, nblocks - 1);
- newpage = BufferGetPage(newbuf);
- }
- else
- {
- newbuf = ReadBuffer(hr, P_NEW);
- newpage = BufferGetPage(newbuf);
- PageInit(newpage, BufferGetPageSize(newbuf), 0);
- }
-
- freespc = IFREESPC(newpage);
-
- /*
- * If there's no room on the last page, allocate a new last page
- * for the table, and put it there.
- */
-
- if (freespc < tupbytes)
- {
- ReleaseBuffer(newbuf);
- newbuf = ReadBuffer(hr, P_NEW);
- newpage = BufferGetPage(newbuf);
- PageInit(newpage, BufferGetPageSize(newbuf), 0);
- }
- }
-
- nwritten = nbytes;
- if (nwritten > obj_desc->highbyte - obj_desc->offset + 1)
- nwritten = obj_desc->highbyte - obj_desc->offset + 1;
- memmove(VARDATA(fsblock) + (obj_desc->offset - obj_desc->lowbyte),
- dbuf, nwritten);
-
- /*
- * we are rewriting the entire old block, therefore we reset offset to
- * the lowbyte of the original block before jumping into
- * inv_newtuple()
- */
- keep_offset = obj_desc->offset;
- obj_desc->offset = obj_desc->lowbyte;
- ntup = inv_newtuple(obj_desc, newbuf, newpage, VARDATA(fsblock),
- tupbytes);
- /* after we are done, we restore to the true offset */
- obj_desc->offset = keep_offset;
-
- /*
- * By here, we have a page (newpage) that's guaranteed to have enough
- * space on it to put the new tuple. Call inv_newtuple to do the
- * work. Passing NULL as a buffer to inv_newtuple() keeps it from
- * copying any data into the new tuple. When it returns, the tuple is
- * ready to receive data from the old tuple and the user's data
- * buffer.
- */
-/*
- ntup = inv_newtuple(obj_desc, newbuf, newpage, (char *) NULL, tupbytes);
- dptr = ((char *) ntup) + ntup->t_hoff -
- (sizeof(HeapTupleData) - offsetof(HeapTupleData, t_bits)) +
- sizeof(int4)
- + sizeof(fsblock->vl_len);
-
- if (obj_desc->offset > obj_desc->lowbyte) {
- memmove(dptr,
- &(fsblock->vl_dat[0]),
- obj_desc->offset - obj_desc->lowbyte);
- dptr += obj_desc->offset - obj_desc->lowbyte;
+static int inv_write_append(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
+ HeapTuple ntup = (HeapTuple) palloc(sizeof(HeapTupleData));
+ Relation idescs[Num_pg_largeobject_indices];
+ Datum values[Natts_pg_largeobject];
+ char nulls[Natts_pg_largeobject];
+ int i;
+ uint32 len;
+
+ for (i=0; i<Natts_pg_largeobject; i++) {
+ nulls[i] = ' ';
+ values[i] = (Datum)NULL;
}
-
- nwritten = nbytes;
- if (nwritten > obj_desc->highbyte - obj_desc->offset + 1)
- nwritten = obj_desc->highbyte - obj_desc->offset + 1;
-
- memmove(dptr, dbuf, nwritten);
- dptr += nwritten;
-
- if (obj_desc->offset + nwritten < obj_desc->highbyte + 1) {
-*/
-/*
- loc = (obj_desc->highbyte - obj_desc->offset)
- + nwritten;
- sz = obj_desc->highbyte - (obj_desc->lowbyte + loc);
-
- what's going on here?? - jolly
-*/
-/*
- sz = (obj_desc->highbyte + 1) - (obj_desc->offset + nwritten);
- memmove(&(fsblock->vl_dat[0]), dptr, sz);
+ i = 0;
+ values[i++] = ObjectIdGetDatum(obj_desc->id);
+ len = (nbytes > IBLKSIZE) ? IBLKSIZE : nbytes;
+
+ values[i++] = Int32GetDatum(obj_desc->offset / IBLKSIZE);
+ values[i++] = (Datum) _byteain(buf, len);
+
+ ntup = heap_formtuple(obj_desc->heap_r->rd_att, values, nulls);
+ heap_insert(obj_desc->heap_r, ntup);
+
+ if (!IsIgnoringSystemIndexes()) {
+ CatalogOpenIndices(Num_pg_largeobject_indices, Name_pg_largeobject_indices, idescs);
+ CatalogIndexInsert(idescs, Num_pg_largeobject_indices, obj_desc->heap_r, ntup);
+ CatalogCloseIndices(Num_pg_largeobject_indices, idescs);
}
-*/
-
-
- /* index the new tuple */
- inv_indextup(obj_desc, ntup);
+
heap_freetuple(ntup);
-
- /*
- * move the scandesc forward so we don't reread the newly inserted
- * tuple on the next index scan
- */
- res = NULL;
- if (obj_desc->iscan)
- res = index_getnext(obj_desc->iscan, ForwardScanDirection);
-
- if (res)
- pfree(res);
-
- /*
- * Okay, by here, a tuple for the new block is correctly placed,
- * indexed, and filled. Write the changed pages out.
- */
-
- WriteBuffer(buffer);
- if (newbuf != buffer)
- WriteBuffer(newbuf);
-
- /* Tuple id is no longer valid */
- ItemPointerSetInvalid(&(obj_desc->htid));
-
- /* done */
- return nwritten;
+
+ return len;
}
+
+static int inv_write_int(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
+ int nwritten = 0;
+ int found = 0;
+
+ if (nbytes == 0)
+ return 0;
-static HeapTuple
-inv_newtuple(LargeObjectDesc *obj_desc,
- Buffer buffer,
- Page page,
- char *dbuf,
- int nwrite)
-{
- HeapTuple ntup = (HeapTuple) palloc(sizeof(HeapTupleData));
- PageHeader ph;
- int tupsize;
- int hoff;
- Offset lower;
- Offset upper;
- ItemId itemId;
- OffsetNumber off;
- OffsetNumber limit;
- char *attptr;
-
- /* compute tuple size -- no nulls */
- hoff = offsetof(HeapTupleHeaderData, t_bits);
- hoff = MAXALIGN(hoff);
-
- /* add in olastbyte, varlena.vl_len, varlena.vl_dat */
- tupsize = hoff + (2 * sizeof(int32)) + nwrite;
- tupsize = MAXALIGN(tupsize);
-
- /*
- * Allocate the tuple on the page, violating the page abstraction.
- * This code was swiped from PageAddItem().
- */
-
- ph = (PageHeader) page;
- limit = OffsetNumberNext(PageGetMaxOffsetNumber(page));
-
- /* look for "recyclable" (unused & deallocated) ItemId */
- for (off = FirstOffsetNumber; off < limit; off = OffsetNumberNext(off))
- {
- itemId = &ph->pd_linp[off - 1];
- if ((((*itemId).lp_flags & LP_USED) == 0) &&
- ((*itemId).lp_len == 0))
- break;
+ nwritten = inv_write_existing(obj_desc, buf, nbytes, &found);
+ if (found > 0) {
+ obj_desc->offset += nwritten;
+ return nwritten;
}
-
- if (off > limit)
- lower = (Offset) (((char *) (&ph->pd_linp[off])) - ((char *) page));
- else if (off == limit)
- lower = ph->pd_lower + sizeof(ItemIdData);
- else
- lower = ph->pd_lower;
-
- upper = ph->pd_upper - tupsize;
-
- itemId = &ph->pd_linp[off - 1];
- (*itemId).lp_off = upper;
- (*itemId).lp_len = tupsize;
- (*itemId).lp_flags = LP_USED;
- ph->pd_lower = lower;
- ph->pd_upper = upper;
-
- ntup->t_datamcxt = NULL;
- ntup->t_data = (HeapTupleHeader) ((char *) page + upper);
-
- /*
- * Tuple is now allocated on the page. Next, fill in the tuple
- * header. This block of code violates the tuple abstraction.
- */
-
- ntup->t_len = tupsize;
- ItemPointerSet(&ntup->t_self, BufferGetBlockNumber(buffer), off);
- ntup->t_data->t_oid = newoid();
- TransactionIdStore(GetCurrentTransactionId(), &(ntup->t_data->t_xmin));
- ntup->t_data->t_cmin = GetCurrentCommandId();
- StoreInvalidTransactionId(&(ntup->t_data->t_xmax));
- ntup->t_data->t_cmax = 0;
- ntup->t_data->t_infomask = HEAP_XMAX_INVALID;
- ntup->t_data->t_natts = 2;
- ntup->t_data->t_hoff = hoff;
-
- /* if a NULL is passed in, avoid the calculations below */
- if (dbuf == NULL)
- return ntup;
-
- /*
- * Finally, copy the user's data buffer into the tuple. This violates
- * the tuple and class abstractions.
- */
-
- attptr = ((char *) ntup->t_data) + hoff;
- *((int32 *) attptr) = obj_desc->offset + nwrite - 1;
- attptr += sizeof(int32);
-
- /*
- * * mer fixed disk layout of varlenas to get rid of the need for
- * this. *
- *
- * ((int32 *) attptr) = nwrite + sizeof(int32); * attptr +=
- * sizeof(int32);
- */
-
- *((int32 *) attptr) = nwrite + sizeof(int32);
- attptr += sizeof(int32);
-
- /*
- * If a data buffer was passed in, then copy the data from the buffer
- * to the tuple. Some callers (eg, inv_wrold()) may not pass in a
- * buffer, since they have to copy part of the old tuple data and part
- * of the user's new data into the new tuple.
- */
-
- if (dbuf != (char *) NULL)
- memmove(attptr, dbuf, nwrite);
-
- /* keep track of boundary of current tuple */
- obj_desc->lowbyte = obj_desc->offset;
- obj_desc->highbyte = obj_desc->offset + nwrite - 1;
-
- /* new tuple is filled -- return it */
- return ntup;
-}
-
-static void
-inv_indextup(LargeObjectDesc *obj_desc, HeapTuple tuple)
-{
- InsertIndexResult res;
- Datum v[1];
- char n[1];
-
- n[0] = ' ';
- v[0] = Int32GetDatum(obj_desc->highbyte);
- res = index_insert(obj_desc->index_r, &v[0], &n[0],
- &(tuple->t_self), obj_desc->heap_r);
-
- if (res)
- pfree(res);
-}
-
-#ifdef NOT_USED
-
-static void
-DumpPage(Page page, int blkno)
-{
- ItemId lp;
- HeapTuple tup;
- int flags, i, nline;
- ItemPointerData pointerData;
-
- printf("\t[subblock=%d]:lower=%d:upper=%d:special=%d\n", 0,
- ((PageHeader)page)->pd_lower, ((PageHeader)page)->pd_upper,
- ((PageHeader)page)->pd_special);
-
- printf("\t:MaxOffsetNumber=%d\n",
- (int16) PageGetMaxOffsetNumber(page));
-
- nline = (int16) PageGetMaxOffsetNumber(page);
-
-{
- int i;
- char *cp;
-
- i = PageGetSpecialSize(page);
- cp = PageGetSpecialPointer(page);
-
- printf("\t:SpecialData=");
-
- while (i > 0) {
- printf(" 0x%02x", *cp);
- cp += 1;
- i -= 1;
- }
- printf("\n");
-}
- for (i = 0; i < nline; i++) {
- lp = ((PageHeader)page)->pd_linp + i;
- flags = (*lp).lp_flags;
- ItemPointerSet(&pointerData, blkno, 1 + i);
- printf("%s:off=%d:flags=0x%x:len=%d",
- ItemPointerFormExternal(&pointerData), (*lp).lp_off,
- flags, (*lp).lp_len);
-
- if (flags & LP_USED) {
- HeapTupleData htdata;
-
- printf(":USED");
-
- memmove((char *) &htdata,
- (char *) &((char *)page)[(*lp).lp_off],
- sizeof(htdata));
-
- tup = &htdata;
-
- printf("\n\t:ctid=%s:oid=%d",
- ItemPointerFormExternal(&tup->t_ctid),
- tup->t_oid);
- printf(":natts=%d:thoff=%d:",
- tup->t_natts,
- tup->t_hoff);
-
- printf("\n\t:cmin=%u:",
- tup->t_cmin);
-
- printf("xmin=%u:", tup->t_xmin);
-
- printf("\n\t:cmax=%u:",
- tup->t_cmax);
-
- printf("xmax=%u:\n", tup->t_xmax);
-
- } else
- putchar('\n');
- }
-}
-
-static char*
-ItemPointerFormExternal(ItemPointer pointer)
-{
- static char itemPointerString[32];
-
- if (!ItemPointerIsValid(pointer)) {
- memmove(itemPointerString, "<-,-,->", sizeof "<-,-,->");
- } else {
- sprintf(itemPointerString, "<%u,%u>",
- ItemPointerGetBlockNumber(pointer),
- ItemPointerGetOffsetNumber(pointer));
- }
-
- return itemPointerString;
+ /* Looks like we are beyond the end of the file */
+ nwritten = inv_write_append(obj_desc, buf, nbytes);
+ obj_desc->offset += nwritten;
+ return nwritten;
}
-#endif
+static int count = 0;
-static int
-_inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln)
-{
- IndexScanDesc iscan;
- RetrieveIndexResult res;
- HeapTupleData tuple;
- Datum d;
- long size;
- bool isNull;
- Buffer buffer;
-
- /* scan backwards from end */
- iscan = index_beginscan(ireln, (bool) 1, 0, (ScanKey) NULL);
-
- do
- {
- res = index_getnext(iscan, BackwardScanDirection);
-
- /*
- * If there are no more index tuples, then the relation is empty,
- * so the file's size is zero.
- */
-
- if (res == (RetrieveIndexResult) NULL)
- {
- index_endscan(iscan);
- return 0;
- }
-
- /*
- * For time travel, we need to use the actual time qual here,
- * rather that NowTimeQual. We currently have no way to pass a
- * time qual in.
- */
- tuple.t_self = res->heap_iptr;
- heap_fetch(hreln, SnapshotNow, &tuple, &buffer);
- pfree(res);
- } while (tuple.t_data == NULL);
-
- /* don't need the index scan anymore */
- index_endscan(iscan);
-
- /* get olastbyte attribute */
- d = heap_getattr(&tuple, 1, hdesc, &isNull);
- size = DatumGetInt32(d) + 1;
- ReleaseBuffer(buffer);
+int
+inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
+ int nwritten = 0;
+ while (nwritten < nbytes)
+ nwritten += inv_write_int(obj_desc, buf + nwritten, nbytes - nwritten);
- return size;
+ return nwritten;
}
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