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165 lines
3.2 KiB
C
165 lines
3.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* temprel.c
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* POSTGRES temporary relation handling
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.10 1999/07/17 20:18:02 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* This implements temp tables by modifying the relname cache lookups
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* of pg_class.
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* When a temp table is created, a linked list of temp table tuples is
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* stored here. When a relname cache lookup is done, references to user-named
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* temp tables are converted to the internal temp table names.
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*
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*/
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#include <sys/types.h>
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#include "postgres.h"
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#include "access/heapam.h"
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#include "catalog/heap.h"
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#include "catalog/index.h"
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#include "utils/temprel.h"
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GlobalMemory CacheCxt;
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/* ----------------
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* global variables
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* ----------------
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*/
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static List *temp_rels = NIL;
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typedef struct TempTable
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{
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char *user_relname;
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HeapTuple pg_class_tuple;
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} TempTable;
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void
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create_temp_relation(char *relname, HeapTuple pg_class_tuple)
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{
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MemoryContext oldcxt;
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TempTable *temp_rel;
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oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
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temp_rel = palloc(sizeof(TempTable));
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temp_rel->user_relname = palloc(NAMEDATALEN);
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/* save user-supplied name */
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strcpy(temp_rel->user_relname, relname);
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temp_rel->pg_class_tuple = heap_copytuple(pg_class_tuple);
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temp_rels = lcons(temp_rel, temp_rels);
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MemoryContextSwitchTo(oldcxt);
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}
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void
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remove_all_temp_relations(void)
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{
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List *l,
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*next;
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AbortOutOfAnyTransaction();
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StartTransactionCommand();
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l = temp_rels;
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while (l != NIL)
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{
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TempTable *temp_rel = lfirst(l);
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Form_pg_class classtuple;
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classtuple = (Form_pg_class) GETSTRUCT(temp_rel->pg_class_tuple);
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next = lnext(l); /* do this first, l is deallocated */
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if (classtuple->relkind != RELKIND_INDEX)
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{
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char relname[NAMEDATALEN];
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/* safe from deallocation */
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strcpy(relname, temp_rel->user_relname);
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heap_destroy_with_catalog(relname);
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}
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else
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index_destroy(temp_rel->pg_class_tuple->t_data->t_oid);
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l = next;
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}
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CommitTransactionCommand();
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}
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/* we don't have the relname for indexes, so we just pass the oid */
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void
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remove_temp_relation(Oid relid)
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{
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MemoryContext oldcxt;
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List *l,
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*prev;
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oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
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prev = NIL;
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l = temp_rels;
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while (l != NIL)
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{
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TempTable *temp_rel = lfirst(l);
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if (temp_rel->pg_class_tuple->t_data->t_oid == relid)
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{
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pfree(temp_rel->user_relname);
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pfree(temp_rel->pg_class_tuple);
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pfree(temp_rel);
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/* remove from linked list */
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if (prev != NIL)
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{
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lnext(prev) = lnext(l);
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pfree(l);
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l = lnext(prev);
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}
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else
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{
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temp_rels = lnext(l);
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pfree(l);
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l = temp_rels;
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}
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}
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else
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{
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prev = l;
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l = lnext(l);
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}
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}
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MemoryContextSwitchTo(oldcxt);
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}
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HeapTuple
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get_temp_rel_by_name(char *user_relname)
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{
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List *l;
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foreach(l, temp_rels)
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{
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TempTable *temp_rel = lfirst(l);
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if (strcmp(temp_rel->user_relname, user_relname) == 0)
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return temp_rel->pg_class_tuple;
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}
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return NULL;
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}
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