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postgresql/src/backend/commands/cluster.c

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/*-------------------------------------------------------------------------
*
* cluster.c--
* Paul Brown's implementation of cluster index.
*
* I am going to use the rename function as a model for this in the
* parser and executor, and the vacuum code as an example in this
* file. As I go - in contrast to the rest of postgres - there will
* be BUCKETS of comments. This is to allow reviewers to understand
* my (probably bogus) assumptions about the way this works.
* [pbrown '94]
*
* Copyright (c) 1994-5, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.9 1996/11/13 20:48:12 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
#include <postgres.h>
#include <catalog/pg_index.h>
#include <catalog/heap.h>
#include <access/heapam.h>
#include <access/genam.h>
#include <access/xact.h>
#include <catalog/catname.h>
#include <utils/syscache.h>
#include <catalog/index.h>
#include <catalog/indexing.h>
#include <catalog/pg_type.h>
#include <commands/copy.h>
#include <commands/cluster.h>
#include <commands/rename.h>
#include <storage/bufmgr.h>
#include <miscadmin.h>
#include <tcop/dest.h>
#include <commands/command.h>
#include <utils/builtins.h>
#include <utils/excid.h>
#include <utils/mcxt.h>
#include <catalog/pg_proc.h>
#include <catalog/pg_class.h>
#include <optimizer/internal.h>
#ifndef NO_SECURITY
#include <utils/acl.h>
#endif /* !NO_SECURITY */
/*
* cluster
*
* Check that the relation is a relation in the appropriate user
* ACL. I will use the same security that limits users on the
* renamerel() function.
*
* Check that the index specified is appropriate for the task
* ( ie it's an index over this relation ). This is trickier.
*
* Create a list of all the other indicies on this relation. Because
* the cluster will wreck all the tids, I'll need to destroy bogus
* indicies. The user will have to re-create them. Not nice, but
* I'm not a nice guy. The alternative is to try some kind of post
* destroy re-build. This may be possible. I'll check out what the
* index create functiond want in the way of paramaters. On the other
* hand, re-creating n indicies may blow out the space.
*
* Create new (temporary) relations for the base heap and the new
* index.
*
* Exclusively lock the relations.
*
* Create new clustered index and base heap relation.
*
*/
void
cluster(char oldrelname[], char oldindexname[])
{
Oid OIDOldHeap, OIDOldIndex, OIDNewHeap;
Relation OldHeap, OldIndex;
Relation NewHeap;
char NewIndexName[NAMEDATALEN+1];
char NewHeapName[NAMEDATALEN+1];
char saveoldrelname[NAMEDATALEN+1];
char saveoldindexname[NAMEDATALEN+1];
/* Save the old names because they will get lost when the old relations
* are destroyed.
*/
strcpy(saveoldrelname, oldrelname);
strcpy(saveoldindexname, oldindexname);
/*
*
* I'm going to force all checking back into the commands.c function.
*
* Get the list if indicies for this relation. If the index we want
* is among them, do not add it to the 'kill' list, as it will be
* handled by the 'clean up' code which commits this transaction.
*
* I'm not using the SysCache, because this will happen but
* once, and the slow way is the sure way in this case.
*
*/
/*
* Like vacuum, cluster spans transactions, so I'm going to handle it in
* the same way.
*/
/* matches the StartTransaction in PostgresMain() */
OldHeap = heap_openr(oldrelname);
if (!RelationIsValid(OldHeap)) {
elog(WARN, "cluster: unknown relation: \"%-.*s\"",
NAMEDATALEN, oldrelname);
}
OIDOldHeap = OldHeap->rd_id; /* Get OID for the index scan */
OldIndex=index_openr(oldindexname);/* Open old index relation */
if (!RelationIsValid(OldIndex)) {
elog(WARN, "cluster: unknown index: \"%-.*s\"",
NAMEDATALEN, oldindexname);
}
OIDOldIndex = OldIndex->rd_id; /* OID for the index scan */
heap_close(OldHeap);
index_close(OldIndex);
/*
* I need to build the copies of the heap and the index. The Commit()
* between here is *very* bogus. If someone is appending stuff, they will
* get the lock after being blocked and add rows which won't be present in
* the new table. Bleagh! I'd be best to try and ensure that no-one's
* in the tables for the entire duration of this process with a pg_vlock.
*/
NewHeap = copy_heap(OIDOldHeap);
OIDNewHeap = NewHeap->rd_id;
strcpy(NewHeapName,NewHeap->rd_rel->relname.data);
/* To make the new heap visible (which is until now empty). */
CommandCounterIncrement();
rebuildheap(OIDNewHeap, OIDOldHeap, OIDOldIndex);
/* To flush the filled new heap (and the statistics about it). */
CommandCounterIncrement();
/* Create new index over the tuples of the new heap. */
copy_index(OIDOldIndex, OIDNewHeap);
sprintf(NewIndexName, "temp_%x", OIDOldIndex);
/*
* make this really happen. Flush all the buffers.
* (Believe me, it is necessary ... ended up in a mess without it.)
*/
CommitTransactionCommand();
StartTransactionCommand();
/* Destroy old heap (along with its index) and rename new. */
heap_destroy(oldrelname);
renamerel(NewHeapName, saveoldrelname);
TypeRename(NewHeapName, saveoldrelname);
renamerel(NewIndexName, saveoldindexname);
/*
* Again flush all the buffers.
*/
CommitTransactionCommand();
StartTransactionCommand();
}
Relation
copy_heap(Oid OIDOldHeap)
{
char NewName[NAMEDATALEN];
TupleDesc OldHeapDesc, tupdesc;
Oid OIDNewHeap;
Relation NewHeap, OldHeap;
/*
* Create a new heap relation with a temporary name, which has the
* same tuple description as the old one.
*/
sprintf(NewName,"temp_%x", OIDOldHeap);
OldHeap= heap_open(OIDOldHeap);
OldHeapDesc= RelationGetTupleDescriptor(OldHeap);
/*
* Need to make a copy of the tuple descriptor, heap_create modifies
* it.
*/
tupdesc = CreateTupleDescCopy(OldHeapDesc);
OIDNewHeap=heap_create(NewName,
NULL,
OldHeap->rd_rel->relarch,
OldHeap->rd_rel->relsmgr,
tupdesc);
if (!OidIsValid(OIDNewHeap))
elog(WARN,"clusterheap: cannot create temporary heap relation\n");
NewHeap=heap_open(OIDNewHeap);
heap_close(NewHeap);
heap_close(OldHeap);
return NewHeap;
}
void
copy_index(Oid OIDOldIndex, Oid OIDNewHeap)
{
Relation OldIndex, NewHeap;
HeapTuple Old_pg_index_Tuple, Old_pg_index_relation_Tuple, pg_proc_Tuple;
IndexTupleForm Old_pg_index_Form;
Form_pg_class Old_pg_index_relation_Form;
Form_pg_proc pg_proc_Form;
char *NewIndexName;
AttrNumber *attnumP;
int natts;
FuncIndexInfo * finfo;
NewHeap = heap_open(OIDNewHeap);
OldIndex = index_open(OIDOldIndex);
/*
* OK. Create a new (temporary) index for the one that's already
* here. To do this I get the info from pg_index, re-build the
* FunctInfo if I have to, and add a new index with a temporary
* name.
*/
Old_pg_index_Tuple =
SearchSysCacheTuple(INDEXRELID,
ObjectIdGetDatum(OldIndex->rd_id),
0,0,0);
Assert(Old_pg_index_Tuple);
Old_pg_index_Form = (IndexTupleForm)GETSTRUCT(Old_pg_index_Tuple);
Old_pg_index_relation_Tuple =
SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(OldIndex->rd_id),
0,0,0);
Assert(Old_pg_index_relation_Tuple);
Old_pg_index_relation_Form =
(Form_pg_class)GETSTRUCT(Old_pg_index_relation_Tuple);
NewIndexName = palloc(NAMEDATALEN+1); /* XXX */
sprintf(NewIndexName, "temp_%x", OIDOldIndex); /* Set the name. */
/*
* Ugly as it is, the only way I have of working out the number of
* attribues is to count them. Mostly there'll be just one but
* I've got to be sure.
*/
for (attnumP = &(Old_pg_index_Form->indkey[0]), natts = 0;
*attnumP != InvalidAttrNumber;
attnumP++, natts++);
/*
* If this is a functional index, I need to rebuild the functional
* component to pass it to the defining procedure.
*/
if (Old_pg_index_Form->indproc != InvalidOid) {
finfo = (FuncIndexInfo *) palloc(sizeof(FuncIndexInfo));
FIgetnArgs(finfo) = natts;
FIgetProcOid(finfo) = Old_pg_index_Form->indproc;
pg_proc_Tuple =
SearchSysCacheTuple(PROOID,
ObjectIdGetDatum(Old_pg_index_Form->indproc),
0,0,0);
Assert(pg_proc_Tuple);
pg_proc_Form = (Form_pg_proc)GETSTRUCT(pg_proc_Tuple);
namecpy(&(finfo->funcName), &(pg_proc_Form->proname));
} else {
finfo = (FuncIndexInfo *) NULL;
natts = 1;
}
index_create((NewHeap->rd_rel->relname).data,
NewIndexName,
finfo,
NULL, /* type info is in the old index */
Old_pg_index_relation_Form->relam,
natts,
Old_pg_index_Form->indkey,
Old_pg_index_Form->indclass,
(uint16)0, (Datum) NULL, NULL,
Old_pg_index_Form->indislossy,
Old_pg_index_Form->indisunique);
heap_close(OldIndex);
heap_close(NewHeap);
}
void
rebuildheap(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
{
Relation LocalNewHeap, LocalOldHeap, LocalOldIndex;
IndexScanDesc ScanDesc;
RetrieveIndexResult ScanResult;
ItemPointer HeapTid;
HeapTuple LocalHeapTuple;
Buffer LocalBuffer;
Oid OIDNewHeapInsert;
/*
* Open the relations I need. Scan through the OldHeap on the OldIndex and
* insert each tuple into the NewHeap.
*/
LocalNewHeap=(Relation)heap_open(OIDNewHeap);
LocalOldHeap=(Relation)heap_open(OIDOldHeap);
LocalOldIndex=(Relation)index_open(OIDOldIndex);
ScanDesc=index_beginscan(LocalOldIndex, false, 0, (ScanKey) NULL);
while ((ScanResult =
index_getnext(ScanDesc, ForwardScanDirection)) != NULL) {
HeapTid = &ScanResult->heap_iptr;
LocalHeapTuple = heap_fetch(LocalOldHeap, 0, HeapTid, &LocalBuffer);
OIDNewHeapInsert =
heap_insert(LocalNewHeap, LocalHeapTuple);
pfree(ScanResult);
ReleaseBuffer(LocalBuffer);
}
index_endscan(ScanDesc);
index_close(LocalOldIndex);
heap_close(LocalOldHeap);
heap_close(LocalNewHeap);
}
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