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Create 'default_tablespace' GUC variable that supplies a TABLESPACE

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clause implicitly whenever one is not given explicitly.  Remove concept
of a schema having an associated tablespace, and simplify the rules for
selecting a default tablespace for a table or index.  It's now just
(a) explicit TABLESPACE clause; (b) default_tablespace if that's not an
empty string; (c) database's default.  This will allow pg_dump to use
SET commands instead of tablespace clauses to determine object locations
(but I didn't actually make it do so).  All per recent discussions.
This commit is contained in:
Tom Lane
2004-11-05 19:17:13 +00:00
parent 0ed3c7665e
commit 98e8b48053
37 changed files with 370 additions and 585 deletions
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225
src/backend/commands/tablespace.c
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@ -3,7 +3,6 @@
* tablespace.c
* Commands to manipulate table spaces
*
*
* Tablespaces in PostgreSQL are designed to allow users to determine
* where the data file(s) for a given database object reside on the file
* system.
@ -26,18 +25,11 @@
* $PGDATA/global/relfilenode
* $PGDATA/base/dboid/relfilenode
*
* The implementation is designed to be backwards compatible. For this reason
* (and also as a feature unto itself) when a user creates an object without
* specifying a tablespace, we look at the object's parent and place
* the object in the parent's tablespace. The hierarchy is as follows:
* database > schema > table > index
*
* To allow CREATE DATABASE to give a new database a default tablespace
* that's different from the template database's default, we make the
* provision that a zero in pg_class.reltablespace means the database's
* default tablespace. Without this, CREATE DATABASE would have to go in
* and munge the system catalogs of the new database. This special meaning
* of zero also applies in pg_namespace.nsptablespace.
* and munge the system catalogs of the new database.
*
*
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
@ -45,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.13 2004/11/05 17:11:05 petere Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.14 2004/11/05 19:15:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -69,10 +61,15 @@
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/* GUC variable */
char *default_tablespace = NULL;
static bool remove_tablespace_directories(Oid tablespaceoid, bool redo);
static void set_short_version(const char *path);
@ -725,77 +722,6 @@ directory_is_empty(const char *path)
return true;
}
/*
* get_tablespace_oid - given a tablespace name, look up the OID
*
* Returns InvalidOid if tablespace name not found.
*/
Oid
get_tablespace_oid(const char *tablespacename)
{
Oid result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/* Search pg_tablespace */
rel = heap_openr(TableSpaceRelationName, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
if (HeapTupleIsValid(tuple))
result = HeapTupleGetOid(tuple);
else
result = InvalidOid;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* get_tablespace_name - given a tablespace OID, look up the name
*
* Returns a palloc'd string, or NULL if no such tablespace.
*/
char *
get_tablespace_name(Oid spc_oid)
{
char *result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/* Search pg_tablespace */
rel = heap_openr(TableSpaceRelationName, AccessShareLock);
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(spc_oid));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = pstrdup(NameStr(((Form_pg_tablespace) GETSTRUCT(tuple))->spcname));
else
result = NULL;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* Rename a tablespace
*/
@ -946,6 +872,143 @@ AlterTableSpaceOwner(const char *name, AclId newOwnerSysId)
heap_close(rel, NoLock);
}
/*
* Routines for handling the GUC variable 'default_tablespace'.
*/
/* assign_hook: validate new default_tablespace, do extra actions as needed */
const char *
assign_default_tablespace(const char *newval, bool doit, GucSource source)
{
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the name. Must accept the value on faith.
*/
if (IsTransactionState())
{
if (newval[0] != '\0' &&
!OidIsValid(get_tablespace_oid(newval)))
{
if (source >= PGC_S_INTERACTIVE)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
newval)));
return NULL;
}
}
return newval;
}
/*
* GetDefaultTablespace -- get the OID of the current default tablespace
*
* May return InvalidOid to indicate "use the database's default tablespace"
*
* This exists to hide (and possibly optimize the use of) the
* default_tablespace GUC variable.
*/
Oid
GetDefaultTablespace(void)
{
Oid result;
/* Fast path for default_tablespace == "" */
if (default_tablespace == NULL || default_tablespace[0] == '\0')
return InvalidOid;
/*
* It is tempting to cache this lookup for more speed, but then we would
* fail to detect the case where the tablespace was dropped since the
* GUC variable was set. Note also that we don't complain if the value
* fails to refer to an existing tablespace; we just silently return
* InvalidOid, causing the new object to be created in the database's
* tablespace.
*/
result = get_tablespace_oid(default_tablespace);
/*
* Allow explicit specification of database's default tablespace in
* default_tablespace without triggering permissions checks.
*/
if (result == MyDatabaseTableSpace)
result = InvalidOid;
return result;
}
/*
* get_tablespace_oid - given a tablespace name, look up the OID
*
* Returns InvalidOid if tablespace name not found.
*/
Oid
get_tablespace_oid(const char *tablespacename)
{
Oid result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/* Search pg_tablespace */
rel = heap_openr(TableSpaceRelationName, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_tablespace_spcname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tablespacename));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
if (HeapTupleIsValid(tuple))
result = HeapTupleGetOid(tuple);
else
result = InvalidOid;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* get_tablespace_name - given a tablespace OID, look up the name
*
* Returns a palloc'd string, or NULL if no such tablespace.
*/
char *
get_tablespace_name(Oid spc_oid)
{
char *result;
Relation rel;
HeapScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/* Search pg_tablespace */
rel = heap_openr(TableSpaceRelationName, AccessShareLock);
ScanKeyInit(&entry[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(spc_oid));
scandesc = heap_beginscan(rel, SnapshotNow, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple))
result = pstrdup(NameStr(((Form_pg_tablespace) GETSTRUCT(tuple))->spcname));
else
result = NULL;
heap_endscan(scandesc);
heap_close(rel, AccessShareLock);
return result;
}
/*
* TABLESPACE resource manager's routines
*/