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postgres/src/backend/commands/dbcommands.c
Peter Eisentraut 04700b685f Rename TransactionChain functions 
We call this thing a "transaction block" everywhere except in a few
functions, where it is mysteriously called a "transaction chain".  In
the SQL standard, a transaction chain is something different.  So rename
these functions to match the common terminology.

Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
2018-03-16 13:18:06 -04:00

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/*-------------------------------------------------------------------------
*
* dbcommands.c
* Database management commands (create/drop database).
*
* Note: database creation/destruction commands use exclusive locks on
* the database objects (as expressed by LockSharedObject()) to avoid
* stepping on each others' toes. Formerly we used table-level locks
* on pg_database, but that's too coarse-grained.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/commands/dbcommands.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/xact.h"
#include "access/xloginsert.h"
#include "access/xlogutils.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_database.h"
#include "catalog/pg_db_role_setting.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/dbcommands_xlog.h"
#include "commands/defrem.h"
#include "commands/seclabel.h"
#include "commands/tablespace.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/bgwriter.h"
#include "replication/slot.h"
#include "storage/copydir.h"
#include "storage/fd.h"
#include "storage/lmgr.h"
#include "storage/ipc.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/pg_locale.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
typedef struct
{
Oid src_dboid; /* source (template) DB */
Oid dest_dboid; /* DB we are trying to create */
} createdb_failure_params;
typedef struct
{
Oid dest_dboid; /* DB we are trying to move */
Oid dest_tsoid; /* tablespace we are trying to move to */
} movedb_failure_params;
/* non-export function prototypes */
static void createdb_failure_callback(int code, Datum arg);
static void movedb(const char *dbname, const char *tblspcname);
static void movedb_failure_callback(int code, Datum arg);
static bool get_db_info(const char *name, LOCKMODE lockmode,
Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP, TransactionId *dbFrozenXidP,
MultiXactId *dbMinMultiP,
Oid *dbTablespace, char **dbCollate, char **dbCtype);
static bool have_createdb_privilege(void);
static void remove_dbtablespaces(Oid db_id);
static bool check_db_file_conflict(Oid db_id);
static int errdetail_busy_db(int notherbackends, int npreparedxacts);
/*
* CREATE DATABASE
*/
Oid
createdb(ParseState *pstate, const CreatedbStmt *stmt)
{
HeapScanDesc scan;
Relation rel;
Oid src_dboid;
Oid src_owner;
int src_encoding;
char *src_collate;
char *src_ctype;
bool src_istemplate;
bool src_allowconn;
Oid src_lastsysoid;
TransactionId src_frozenxid;
MultiXactId src_minmxid;
Oid src_deftablespace;
volatile Oid dst_deftablespace;
Relation pg_database_rel;
HeapTuple tuple;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
Oid dboid;
Oid datdba;
ListCell *option;
DefElem *dtablespacename = NULL;
DefElem *downer = NULL;
DefElem *dtemplate = NULL;
DefElem *dencoding = NULL;
DefElem *dcollate = NULL;
DefElem *dctype = NULL;
DefElem *distemplate = NULL;
DefElem *dallowconnections = NULL;
DefElem *dconnlimit = NULL;
char *dbname = stmt->dbname;
char *dbowner = NULL;
const char *dbtemplate = NULL;
char *dbcollate = NULL;
char *dbctype = NULL;
char *canonname;
int encoding = -1;
bool dbistemplate = false;
bool dballowconnections = true;
int dbconnlimit = -1;
int notherbackends;
int npreparedxacts;
createdb_failure_params fparms;
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
if (strcmp(defel->defname, "tablespace") == 0)
{
if (dtablespacename)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtablespacename = defel;
}
else if (strcmp(defel->defname, "owner") == 0)
{
if (downer)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
downer = defel;
}
else if (strcmp(defel->defname, "template") == 0)
{
if (dtemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtemplate = defel;
}
else if (strcmp(defel->defname, "encoding") == 0)
{
if (dencoding)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dencoding = defel;
}
else if (strcmp(defel->defname, "lc_collate") == 0)
{
if (dcollate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dcollate = defel;
}
else if (strcmp(defel->defname, "lc_ctype") == 0)
{
if (dctype)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dctype = defel;
}
else if (strcmp(defel->defname, "is_template") == 0)
{
if (distemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
distemplate = defel;
}
else if (strcmp(defel->defname, "allow_connections") == 0)
{
if (dallowconnections)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dallowconnections = defel;
}
else if (strcmp(defel->defname, "connection_limit") == 0)
{
if (dconnlimit)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dconnlimit = defel;
}
else if (strcmp(defel->defname, "location") == 0)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("LOCATION is not supported anymore"),
errhint("Consider using tablespaces instead."),
parser_errposition(pstate, defel->location)));
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("option \"%s\" not recognized", defel->defname),
parser_errposition(pstate, defel->location)));
}
if (downer && downer->arg)
dbowner = defGetString(downer);
if (dtemplate && dtemplate->arg)
dbtemplate = defGetString(dtemplate);
if (dencoding && dencoding->arg)
{
const char *encoding_name;
if (IsA(dencoding->arg, Integer))
{
encoding = defGetInt32(dencoding);
encoding_name = pg_encoding_to_char(encoding);
if (strcmp(encoding_name, "") == 0 ||
pg_valid_server_encoding(encoding_name) < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%d is not a valid encoding code",
encoding),
parser_errposition(pstate, dencoding->location)));
}
else
{
encoding_name = defGetString(dencoding);
encoding = pg_valid_server_encoding(encoding_name);
if (encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%s is not a valid encoding name",
encoding_name),
parser_errposition(pstate, dencoding->location)));
}
}
if (dcollate && dcollate->arg)
dbcollate = defGetString(dcollate);
if (dctype && dctype->arg)
dbctype = defGetString(dctype);
if (distemplate && distemplate->arg)
dbistemplate = defGetBoolean(distemplate);
if (dallowconnections && dallowconnections->arg)
dballowconnections = defGetBoolean(dallowconnections);
if (dconnlimit && dconnlimit->arg)
{
dbconnlimit = defGetInt32(dconnlimit);
if (dbconnlimit < -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid connection limit: %d", dbconnlimit)));
}
/* obtain OID of proposed owner */
if (dbowner)
datdba = get_role_oid(dbowner, false);
else
datdba = GetUserId();
/*
* To create a database, must have createdb privilege and must be able to
* become the target role (this does not imply that the target role itself
* must have createdb privilege). The latter provision guards against
* "giveaway" attacks. Note that a superuser will always have both of
* these privileges a fortiori.
*/
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create database")));
check_is_member_of_role(GetUserId(), datdba);
/*
* Lookup database (template) to be cloned, and obtain share lock on it.
* ShareLock allows two CREATE DATABASEs to work from the same template
* concurrently, while ensuring no one is busy dropping it in parallel
* (which would be Very Bad since we'd likely get an incomplete copy
* without knowing it). This also prevents any new connections from being
* made to the source until we finish copying it, so we can be sure it
* won't change underneath us.
*/
if (!dbtemplate)
dbtemplate = "template1"; /* Default template database name */
if (!get_db_info(dbtemplate, ShareLock,
&src_dboid, &src_owner, &src_encoding,
&src_istemplate, &src_allowconn, &src_lastsysoid,
&src_frozenxid, &src_minmxid, &src_deftablespace,
&src_collate, &src_ctype))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("template database \"%s\" does not exist",
dbtemplate)));
/*
* Permission check: to copy a DB that's not marked datistemplate, you
* must be superuser or the owner thereof.
*/
if (!src_istemplate)
{
if (!pg_database_ownercheck(src_dboid, GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to copy database \"%s\"",
dbtemplate)));
}
/* If encoding or locales are defaulted, use source's setting */
if (encoding < 0)
encoding = src_encoding;
if (dbcollate == NULL)
dbcollate = src_collate;
if (dbctype == NULL)
dbctype = src_ctype;
/* Some encodings are client only */
if (!PG_VALID_BE_ENCODING(encoding))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid server encoding %d", encoding)));
/* Check that the chosen locales are valid, and get canonical spellings */
if (!check_locale(LC_COLLATE, dbcollate, &canonname))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid locale name: \"%s\"", dbcollate)));
dbcollate = canonname;
if (!check_locale(LC_CTYPE, dbctype, &canonname))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid locale name: \"%s\"", dbctype)));
dbctype = canonname;
check_encoding_locale_matches(encoding, dbcollate, dbctype);
/*
* Check that the new encoding and locale settings match the source
* database. We insist on this because we simply copy the source data ---
* any non-ASCII data would be wrongly encoded, and any indexes sorted
* according to the source locale would be wrong.
*
* However, we assume that template0 doesn't contain any non-ASCII data
* nor any indexes that depend on collation or ctype, so template0 can be
* used as template for creating a database with any encoding or locale.
*/
if (strcmp(dbtemplate, "template0") != 0)
{
if (encoding != src_encoding)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new encoding (%s) is incompatible with the encoding of the template database (%s)",
pg_encoding_to_char(encoding),
pg_encoding_to_char(src_encoding)),
errhint("Use the same encoding as in the template database, or use template0 as template.")));
if (strcmp(dbcollate, src_collate) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new collation (%s) is incompatible with the collation of the template database (%s)",
dbcollate, src_collate),
errhint("Use the same collation as in the template database, or use template0 as template.")));
if (strcmp(dbctype, src_ctype) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new LC_CTYPE (%s) is incompatible with the LC_CTYPE of the template database (%s)",
dbctype, src_ctype),
errhint("Use the same LC_CTYPE as in the template database, or use template0 as template.")));
}
/* Resolve default tablespace for new database */
if (dtablespacename && dtablespacename->arg)
{
char *tablespacename;
AclResult aclresult;
tablespacename = defGetString(dtablespacename);
dst_deftablespace = get_tablespace_oid(tablespacename, false);
/* check permissions */
aclresult = pg_tablespace_aclcheck(dst_deftablespace, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_TABLESPACE,
tablespacename);
/* pg_global must never be the default tablespace */
if (dst_deftablespace == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("pg_global cannot be used as default tablespace")));
/*
* If we are trying to change the default tablespace of the template,
* we require that the template not have any files in the new default
* tablespace. This is necessary because otherwise the copied
* database would contain pg_class rows that refer to its default
* tablespace both explicitly (by OID) and implicitly (as zero), which
* would cause problems. For example another CREATE DATABASE using
* the copied database as template, and trying to change its default
* tablespace again, would yield outright incorrect results (it would
* improperly move tables to the new default tablespace that should
* stay in the same tablespace).
*/
if (dst_deftablespace != src_deftablespace)
{
char *srcpath;
struct stat st;
srcpath = GetDatabasePath(src_dboid, dst_deftablespace);
if (stat(srcpath, &st) == 0 &&
S_ISDIR(st.st_mode) &&
!directory_is_empty(srcpath))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot assign new default tablespace \"%s\"",
tablespacename),
errdetail("There is a conflict because database \"%s\" already has some tables in this tablespace.",
dbtemplate)));
pfree(srcpath);
}
}
else
{
/* Use template database's default tablespace */
dst_deftablespace = src_deftablespace;
/* Note there is no additional permission check in this path */
}
/*
* Check for db name conflict. This is just to give a more friendly error
* message than "unique index violation". There's a race condition but
* we're willing to accept the less friendly message in that case.
*/
if (OidIsValid(get_database_oid(dbname, true)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
/*
* The source DB can't have any active backends, except this one
* (exception is to allow CREATE DB while connected to template1).
* Otherwise we might copy inconsistent data.
*
* This should be last among the basic error checks, because it involves
* potential waiting; we may as well throw an error first if we're gonna
* throw one.
*/
if (CountOtherDBBackends(src_dboid, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("source database \"%s\" is being accessed by other users",
dbtemplate),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Select an OID for the new database, checking that it doesn't have a
* filename conflict with anything already existing in the tablespace
* directories.
*/
pg_database_rel = heap_open(DatabaseRelationId, RowExclusiveLock);
do
{
dboid = GetNewOid(pg_database_rel);
} while (check_db_file_conflict(dboid));
/*
* Insert a new tuple into pg_database. This establishes our ownership of
* the new database name (anyone else trying to insert the same name will
* block on the unique index, and fail after we commit).
*/
/* Form tuple */
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
new_record[Anum_pg_database_datname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbname));
new_record[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(datdba);
new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
new_record[Anum_pg_database_datcollate - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbcollate));
new_record[Anum_pg_database_datctype - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbctype));
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(dbistemplate);
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(dballowconnections);
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record[Anum_pg_database_datlastsysoid - 1] = ObjectIdGetDatum(src_lastsysoid);
new_record[Anum_pg_database_datfrozenxid - 1] = TransactionIdGetDatum(src_frozenxid);
new_record[Anum_pg_database_datminmxid - 1] = TransactionIdGetDatum(src_minmxid);
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_deftablespace);
/*
* We deliberately set datacl to default (NULL), rather than copying it
* from the template database. Copying it would be a bad idea when the
* owner is not the same as the template's owner.
*/
new_record_nulls[Anum_pg_database_datacl - 1] = true;
tuple = heap_form_tuple(RelationGetDescr(pg_database_rel),
new_record, new_record_nulls);
HeapTupleSetOid(tuple, dboid);
CatalogTupleInsert(pg_database_rel, tuple);
/*
* Now generate additional catalog entries associated with the new DB
*/
/* Register owner dependency */
recordDependencyOnOwner(DatabaseRelationId, dboid, datdba);
/* Create pg_shdepend entries for objects within database */
copyTemplateDependencies(src_dboid, dboid);
/* Post creation hook for new database */
InvokeObjectPostCreateHook(DatabaseRelationId, dboid, 0);
/*
* Force a checkpoint before starting the copy. This will force all dirty
* buffers, including those of unlogged tables, out to disk, to ensure
* source database is up-to-date on disk for the copy.
* FlushDatabaseBuffers() would suffice for that, but we also want to
* process any pending unlink requests. Otherwise, if a checkpoint
* happened while we're copying files, a file might be deleted just when
* we're about to copy it, causing the lstat() call in copydir() to fail
* with ENOENT.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT
| CHECKPOINT_FLUSH_ALL);
/*
* Once we start copying subdirectories, we need to be able to clean 'em
* up if we fail. Use an ENSURE block to make sure this happens. (This
* is not a 100% solution, because of the possibility of failure during
* transaction commit after we leave this routine, but it should handle
* most scenarios.)
*/
fparms.src_dboid = src_dboid;
fparms.dest_dboid = dboid;
PG_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
PointerGetDatum(&fparms));
{
/*
* Iterate through all tablespaces of the template database, and copy
* each one to the new database.
*/
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Oid srctablespace = HeapTupleGetOid(tuple);
Oid dsttablespace;
char *srcpath;
char *dstpath;
struct stat st;
/* No need to copy global tablespace */
if (srctablespace == GLOBALTABLESPACE_OID)
continue;
srcpath = GetDatabasePath(src_dboid, srctablespace);
if (stat(srcpath, &st) < 0 || !S_ISDIR(st.st_mode) ||
directory_is_empty(srcpath))
{
/* Assume we can ignore it */
pfree(srcpath);
continue;
}
if (srctablespace == src_deftablespace)
dsttablespace = dst_deftablespace;
else
dsttablespace = srctablespace;
dstpath = GetDatabasePath(dboid, dsttablespace);
/*
* Copy this subdirectory to the new location
*
* We don't need to copy subdirectories
*/
copydir(srcpath, dstpath, false);
/* Record the filesystem change in XLOG */
{
xl_dbase_create_rec xlrec;
xlrec.db_id = dboid;
xlrec.tablespace_id = dsttablespace;
xlrec.src_db_id = src_dboid;
xlrec.src_tablespace_id = srctablespace;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_create_rec));
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_CREATE | XLR_SPECIAL_REL_UPDATE);
}
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* We force a checkpoint before committing. This effectively means
* that committed XLOG_DBASE_CREATE operations will never need to be
* replayed (at least not in ordinary crash recovery; we still have to
* make the XLOG entry for the benefit of PITR operations). This
* avoids two nasty scenarios:
*
* #1: When PITR is off, we don't XLOG the contents of newly created
* indexes; therefore the drop-and-recreate-whole-directory behavior
* of DBASE_CREATE replay would lose such indexes.
*
* #2: Since we have to recopy the source database during DBASE_CREATE
* replay, we run the risk of copying changes in it that were
* committed after the original CREATE DATABASE command but before the
* system crash that led to the replay. This is at least unexpected
* and at worst could lead to inconsistencies, eg duplicate table
* names.
*
* (Both of these were real bugs in releases 8.0 through 8.0.3.)
*
* In PITR replay, the first of these isn't an issue, and the second
* is only a risk if the CREATE DATABASE and subsequent template
* database change both occur while a base backup is being taken.
* There doesn't seem to be much we can do about that except document
* it as a limitation.
*
* Perhaps if we ever implement CREATE DATABASE in a less cheesy way,
* we can avoid this.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Close pg_database, but keep lock till commit.
*/
heap_close(pg_database_rel, NoLock);
/*
* Force synchronous commit, thus minimizing the window between
* creation of the database files and committal of the transaction. If
* we crash before committing, we'll have a DB that's taking up disk
* space but is not in pg_database, which is not good.
*/
ForceSyncCommit();
}
PG_END_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
PointerGetDatum(&fparms));
return dboid;
}
/*
* Check whether chosen encoding matches chosen locale settings. This
* restriction is necessary because libc's locale-specific code usually
* fails when presented with data in an encoding it's not expecting. We
* allow mismatch in four cases:
*
* 1. locale encoding = SQL_ASCII, which means that the locale is C/POSIX
* which works with any encoding.
*
* 2. locale encoding = -1, which means that we couldn't determine the
* locale's encoding and have to trust the user to get it right.
*
* 3. selected encoding is UTF8 and platform is win32. This is because
* UTF8 is a pseudo codepage that is supported in all locales since it's
* converted to UTF16 before being used.
*
* 4. selected encoding is SQL_ASCII, but only if you're a superuser. This
* is risky but we have historically allowed it --- notably, the
* regression tests require it.
*
* Note: if you change this policy, fix initdb to match.
*/
void
check_encoding_locale_matches(int encoding, const char *collate, const char *ctype)
{
int ctype_encoding = pg_get_encoding_from_locale(ctype, true);
int collate_encoding = pg_get_encoding_from_locale(collate, true);
if (!(ctype_encoding == encoding ||
ctype_encoding == PG_SQL_ASCII ||
ctype_encoding == -1 ||
#ifdef WIN32
encoding == PG_UTF8 ||
#endif
(encoding == PG_SQL_ASCII && superuser())))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("encoding \"%s\" does not match locale \"%s\"",
pg_encoding_to_char(encoding),
ctype),
errdetail("The chosen LC_CTYPE setting requires encoding \"%s\".",
pg_encoding_to_char(ctype_encoding))));
if (!(collate_encoding == encoding ||
collate_encoding == PG_SQL_ASCII ||
collate_encoding == -1 ||
#ifdef WIN32
encoding == PG_UTF8 ||
#endif
(encoding == PG_SQL_ASCII && superuser())))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("encoding \"%s\" does not match locale \"%s\"",
pg_encoding_to_char(encoding),
collate),
errdetail("The chosen LC_COLLATE setting requires encoding \"%s\".",
pg_encoding_to_char(collate_encoding))));
}
/* Error cleanup callback for createdb */
static void
createdb_failure_callback(int code, Datum arg)
{
createdb_failure_params *fparms = (createdb_failure_params *) DatumGetPointer(arg);
/*
* Release lock on source database before doing recursive remove. This is
* not essential but it seems desirable to release the lock as soon as
* possible.
*/
UnlockSharedObject(DatabaseRelationId, fparms->src_dboid, 0, ShareLock);
/* Throw away any successfully copied subdirectories */
remove_dbtablespaces(fparms->dest_dboid);
}
/*
* DROP DATABASE
*/
void
dropdb(const char *dbname, bool missing_ok)
{
Oid db_id;
bool db_istemplate;
Relation pgdbrel;
HeapTuple tup;
int notherbackends;
int npreparedxacts;
int nslots,
nslots_active;
int nsubscriptions;
/*
* Look up the target database's OID, and get exclusive lock on it. We
* need this to ensure that no new backend starts up in the target
* database while we are deleting it (see postinit.c), and that no one is
* using it as a CREATE DATABASE template or trying to delete it for
* themselves.
*/
pgdbrel = heap_open(DatabaseRelationId, RowExclusiveLock);
if (!get_db_info(dbname, AccessExclusiveLock, &db_id, NULL, NULL,
&db_istemplate, NULL, NULL, NULL, NULL, NULL, NULL, NULL))
{
if (!missing_ok)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
}
else
{
/* Close pg_database, release the lock, since we changed nothing */
heap_close(pgdbrel, RowExclusiveLock);
ereport(NOTICE,
(errmsg("database \"%s\" does not exist, skipping",
dbname)));
return;
}
}
/*
* Permission checks
*/
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/* DROP hook for the database being removed */
InvokeObjectDropHook(DatabaseRelationId, db_id, 0);
/*
* Disallow dropping a DB that is marked istemplate. This is just to
* prevent people from accidentally dropping template0 or template1; they
* can do so if they're really determined ...
*/
if (db_istemplate)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot drop a template database")));
/* Obviously can't drop my own database */
if (db_id == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot drop the currently open database")));
/*
* Check whether there are active logical slots that refer to the
* to-be-dropped database. The database lock we are holding prevents the
* creation of new slots using the database or existing slots becoming
* active.
*/
(void) ReplicationSlotsCountDBSlots(db_id, &nslots, &nslots_active);
if (nslots_active)
{
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is used by an active logical replication slot",
dbname),
errdetail_plural("There is %d active slot.",
"There are %d active slots.",
nslots_active, nslots_active)));
}
/*
* Check for other backends in the target database. (Because we hold the
* database lock, no new ones can start after this.)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
dbname),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Check if there are subscriptions defined in the target database.
*
* We can't drop them automatically because they might be holding
* resources in other databases/instances.
*/
if ((nsubscriptions = CountDBSubscriptions(db_id)) > 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being used by logical replication subscription",
dbname),
errdetail_plural("There is %d subscription.",
"There are %d subscriptions.",
nsubscriptions, nsubscriptions)));
/*
* Remove the database's tuple from pg_database.
*/
tup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(db_id));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for database %u", db_id);
CatalogTupleDelete(pgdbrel, &tup->t_self);
ReleaseSysCache(tup);
/*
* Delete any comments or security labels associated with the database.
*/
DeleteSharedComments(db_id, DatabaseRelationId);
DeleteSharedSecurityLabel(db_id, DatabaseRelationId);
/*
* Remove settings associated with this database
*/
DropSetting(db_id, InvalidOid);
/*
* Remove shared dependency references for the database.
*/
dropDatabaseDependencies(db_id);
/*
* Drop db-specific replication slots.
*/
ReplicationSlotsDropDBSlots(db_id);
/*
* Drop pages for this database that are in the shared buffer cache. This
* is important to ensure that no remaining backend tries to write out a
* dirty buffer to the dead database later...
*/
DropDatabaseBuffers(db_id);
/*
* Tell the stats collector to forget it immediately, too.
*/
pgstat_drop_database(db_id);
/*
* Tell checkpointer to forget any pending fsync and unlink requests for
* files in the database; else the fsyncs will fail at next checkpoint, or
* worse, it will delete files that belong to a newly created database
* with the same OID.
*/
ForgetDatabaseFsyncRequests(db_id);
/*
* Force a checkpoint to make sure the checkpointer has received the
* message sent by ForgetDatabaseFsyncRequests. On Windows, this also
* ensures that background procs don't hold any open files, which would
* cause rmdir() to fail.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Remove all tablespace subdirs belonging to the database.
*/
remove_dbtablespaces(db_id);
/*
* Close pg_database, but keep lock till commit.
*/
heap_close(pgdbrel, NoLock);
/*
* Force synchronous commit, thus minimizing the window between removal of
* the database files and committal of the transaction. If we crash before
* committing, we'll have a DB that's gone on disk but still there
* according to pg_database, which is not good.
*/
ForceSyncCommit();
}
/*
* Rename database
*/
ObjectAddress
RenameDatabase(const char *oldname, const char *newname)
{
Oid db_id;
HeapTuple newtup;
Relation rel;
int notherbackends;
int npreparedxacts;
ObjectAddress address;
/*
* Look up the target database's OID, and get exclusive lock on it. We
* need this for the same reasons as DROP DATABASE.
*/
rel = heap_open(DatabaseRelationId, RowExclusiveLock);
if (!get_db_info(oldname, AccessExclusiveLock, &db_id, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", oldname)));
/* must be owner */
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
oldname);
/* must have createdb rights */
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to rename database")));
/*
* Make sure the new name doesn't exist. See notes for same error in
* CREATE DATABASE.
*/
if (OidIsValid(get_database_oid(newname, true)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", newname)));
/*
* XXX Client applications probably store the current database somewhere,
* so renaming it could cause confusion. On the other hand, there may not
* be an actual problem besides a little confusion, so think about this
* and decide.
*/
if (db_id == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("current database cannot be renamed")));
/*
* Make sure the database does not have active sessions. This is the same
* concern as above, but applied to other sessions.
*
* As in CREATE DATABASE, check this after other error conditions.
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
oldname),
errdetail_busy_db(notherbackends, npreparedxacts)));
/* rename */
newtup = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(db_id));
if (!HeapTupleIsValid(newtup))
elog(ERROR, "cache lookup failed for database %u", db_id);
namestrcpy(&(((Form_pg_database) GETSTRUCT(newtup))->datname), newname);
CatalogTupleUpdate(rel, &newtup->t_self, newtup);
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
ObjectAddressSet(address, DatabaseRelationId, db_id);
/*
* Close pg_database, but keep lock till commit.
*/
heap_close(rel, NoLock);
return address;
}
/*
* ALTER DATABASE SET TABLESPACE
*/
static void
movedb(const char *dbname, const char *tblspcname)
{
Oid db_id;
Relation pgdbrel;
int notherbackends;
int npreparedxacts;
HeapTuple oldtuple,
newtuple;
Oid src_tblspcoid,
dst_tblspcoid;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
bool new_record_repl[Natts_pg_database];
ScanKeyData scankey;
SysScanDesc sysscan;
AclResult aclresult;
char *src_dbpath;
char *dst_dbpath;
DIR *dstdir;
struct dirent *xlde;
movedb_failure_params fparms;
/*
* Look up the target database's OID, and get exclusive lock on it. We
* need this to ensure that no new backend starts up in the database while
* we are moving it, and that no one is using it as a CREATE DATABASE
* template or trying to delete it.
*/
pgdbrel = heap_open(DatabaseRelationId, RowExclusiveLock);
if (!get_db_info(dbname, AccessExclusiveLock, &db_id, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, &src_tblspcoid, NULL, NULL))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
/*
* We actually need a session lock, so that the lock will persist across
* the commit/restart below. (We could almost get away with letting the
* lock be released at commit, except that someone could try to move
* relations of the DB back into the old directory while we rmtree() it.)
*/
LockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
/*
* Permission checks
*/
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/*
* Obviously can't move the tables of my own database
*/
if (db_id == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot change the tablespace of the currently open database")));
/*
* Get tablespace's oid
*/
dst_tblspcoid = get_tablespace_oid(tblspcname, false);
/*
* Permission checks
*/
aclresult = pg_tablespace_aclcheck(dst_tblspcoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_TABLESPACE,
tblspcname);
/*
* pg_global must never be the default tablespace
*/
if (dst_tblspcoid == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("pg_global cannot be used as default tablespace")));
/*
* No-op if same tablespace
*/
if (src_tblspcoid == dst_tblspcoid)
{
heap_close(pgdbrel, NoLock);
UnlockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
return;
}
/*
* Check for other backends in the target database. (Because we hold the
* database lock, no new ones can start after this.)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
dbname),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Get old and new database paths
*/
src_dbpath = GetDatabasePath(db_id, src_tblspcoid);
dst_dbpath = GetDatabasePath(db_id, dst_tblspcoid);
/*
* Force a checkpoint before proceeding. This will force all dirty
* buffers, including those of unlogged tables, out to disk, to ensure
* source database is up-to-date on disk for the copy.
* FlushDatabaseBuffers() would suffice for that, but we also want to
* process any pending unlink requests. Otherwise, the check for existing
* files in the target directory might fail unnecessarily, not to mention
* that the copy might fail due to source files getting deleted under it.
* On Windows, this also ensures that background procs don't hold any open
* files, which would cause rmdir() to fail.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT
| CHECKPOINT_FLUSH_ALL);
/*
* Now drop all buffers holding data of the target database; they should
* no longer be dirty so DropDatabaseBuffers is safe.
*
* It might seem that we could just let these buffers age out of shared
* buffers naturally, since they should not get referenced anymore. The
* problem with that is that if the user later moves the database back to
* its original tablespace, any still-surviving buffers would appear to
* contain valid data again --- but they'd be missing any changes made in
* the database while it was in the new tablespace. In any case, freeing
* buffers that should never be used again seems worth the cycles.
*
* Note: it'd be sufficient to get rid of buffers matching db_id and
* src_tblspcoid, but bufmgr.c presently provides no API for that.
*/
DropDatabaseBuffers(db_id);
/*
* Check for existence of files in the target directory, i.e., objects of
* this database that are already in the target tablespace. We can't
* allow the move in such a case, because we would need to change those
* relations' pg_class.reltablespace entries to zero, and we don't have
* access to the DB's pg_class to do so.
*/
dstdir = AllocateDir(dst_dbpath);
if (dstdir != NULL)
{
while ((xlde = ReadDir(dstdir, dst_dbpath)) != NULL)
{
if (strcmp(xlde->d_name, ".") == 0 ||
strcmp(xlde->d_name, "..") == 0)
continue;
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("some relations of database \"%s\" are already in tablespace \"%s\"",
dbname, tblspcname),
errhint("You must move them back to the database's default tablespace before using this command.")));
}
FreeDir(dstdir);
/*
* The directory exists but is empty. We must remove it before using
* the copydir function.
*/
if (rmdir(dst_dbpath) != 0)
elog(ERROR, "could not remove directory \"%s\": %m",
dst_dbpath);
}
/*
* Use an ENSURE block to make sure we remove the debris if the copy fails
* (eg, due to out-of-disk-space). This is not a 100% solution, because
* of the possibility of failure during transaction commit, but it should
* handle most scenarios.
*/
fparms.dest_dboid = db_id;
fparms.dest_tsoid = dst_tblspcoid;
PG_ENSURE_ERROR_CLEANUP(movedb_failure_callback,
PointerGetDatum(&fparms));
{
/*
* Copy files from the old tablespace to the new one
*/
copydir(src_dbpath, dst_dbpath, false);
/*
* Record the filesystem change in XLOG
*/
{
xl_dbase_create_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = dst_tblspcoid;
xlrec.src_db_id = db_id;
xlrec.src_tablespace_id = src_tblspcoid;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_create_rec));
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_CREATE | XLR_SPECIAL_REL_UPDATE);
}
/*
* Update the database's pg_database tuple
*/
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
sysscan = systable_beginscan(pgdbrel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
oldtuple = systable_getnext(sysscan);
if (!HeapTupleIsValid(oldtuple)) /* shouldn't happen... */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
MemSet(new_record_repl, false, sizeof(new_record_repl));
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_tblspcoid);
new_record_repl[Anum_pg_database_dattablespace - 1] = true;
newtuple = heap_modify_tuple(oldtuple, RelationGetDescr(pgdbrel),
new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(pgdbrel, &oldtuple->t_self, newtuple);
InvokeObjectPostAlterHook(DatabaseRelationId,
HeapTupleGetOid(newtuple), 0);
systable_endscan(sysscan);
/*
* Force another checkpoint here. As in CREATE DATABASE, this is to
* ensure that we don't have to replay a committed XLOG_DBASE_CREATE
* operation, which would cause us to lose any unlogged operations
* done in the new DB tablespace before the next checkpoint.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Force synchronous commit, thus minimizing the window between
* copying the database files and committal of the transaction. If we
* crash before committing, we'll leave an orphaned set of files on
* disk, which is not fatal but not good either.
*/
ForceSyncCommit();
/*
* Close pg_database, but keep lock till commit.
*/
heap_close(pgdbrel, NoLock);
}
PG_END_ENSURE_ERROR_CLEANUP(movedb_failure_callback,
PointerGetDatum(&fparms));
/*
* Commit the transaction so that the pg_database update is committed. If
* we crash while removing files, the database won't be corrupt, we'll
* just leave some orphaned files in the old directory.
*
* (This is OK because we know we aren't inside a transaction block.)
*
* XXX would it be safe/better to do this inside the ensure block? Not
* convinced it's a good idea; consider elog just after the transaction
* really commits.
*/
PopActiveSnapshot();
CommitTransactionCommand();
/* Start new transaction for the remaining work; don't need a snapshot */
StartTransactionCommand();
/*
* Remove files from the old tablespace
*/
if (!rmtree(src_dbpath, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
src_dbpath)));
/*
* Record the filesystem change in XLOG
*/
{
xl_dbase_drop_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = src_tblspcoid;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_drop_rec));
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_DROP | XLR_SPECIAL_REL_UPDATE);
}
/* Now it's safe to release the database lock */
UnlockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
}
/* Error cleanup callback for movedb */
static void
movedb_failure_callback(int code, Datum arg)
{
movedb_failure_params *fparms = (movedb_failure_params *) DatumGetPointer(arg);
char *dstpath;
/* Get rid of anything we managed to copy to the target directory */
dstpath = GetDatabasePath(fparms->dest_dboid, fparms->dest_tsoid);
(void) rmtree(dstpath, true);
}
/*
* ALTER DATABASE name ...
*/
Oid
AlterDatabase(ParseState *pstate, AlterDatabaseStmt *stmt, bool isTopLevel)
{
Relation rel;
Oid dboid;
HeapTuple tuple,
newtuple;
ScanKeyData scankey;
SysScanDesc scan;
ListCell *option;
bool dbistemplate = false;
bool dballowconnections = true;
int dbconnlimit = -1;
DefElem *distemplate = NULL;
DefElem *dallowconnections = NULL;
DefElem *dconnlimit = NULL;
DefElem *dtablespace = NULL;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
bool new_record_repl[Natts_pg_database];
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
if (strcmp(defel->defname, "is_template") == 0)
{
if (distemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
distemplate = defel;
}
else if (strcmp(defel->defname, "allow_connections") == 0)
{
if (dallowconnections)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dallowconnections = defel;
}
else if (strcmp(defel->defname, "connection_limit") == 0)
{
if (dconnlimit)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dconnlimit = defel;
}
else if (strcmp(defel->defname, "tablespace") == 0)
{
if (dtablespace)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtablespace = defel;
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("option \"%s\" not recognized", defel->defname),
parser_errposition(pstate, defel->location)));
}
if (dtablespace)
{
/*
* While the SET TABLESPACE syntax doesn't allow any other options,
* somebody could write "WITH TABLESPACE ...". Forbid any other
* options from being specified in that case.
*/
if (list_length(stmt->options) != 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("option \"%s\" cannot be specified with other options",
dtablespace->defname),
parser_errposition(pstate, dtablespace->location)));
/* this case isn't allowed within a transaction block */
PreventInTransactionBlock(isTopLevel, "ALTER DATABASE SET TABLESPACE");
movedb(stmt->dbname, defGetString(dtablespace));
return InvalidOid;
}
if (distemplate && distemplate->arg)
dbistemplate = defGetBoolean(distemplate);
if (dallowconnections && dallowconnections->arg)
dballowconnections = defGetBoolean(dallowconnections);
if (dconnlimit && dconnlimit->arg)
{
dbconnlimit = defGetInt32(dconnlimit);
if (dbconnlimit < -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid connection limit: %d", dbconnlimit)));
}
/*
* Get the old tuple. We don't need a lock on the database per se,
* because we're not going to do anything that would mess up incoming
* connections.
*/
rel = heap_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(stmt->dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", stmt->dbname)));
dboid = HeapTupleGetOid(tuple);
if (!pg_database_ownercheck(HeapTupleGetOid(tuple), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
stmt->dbname);
/*
* In order to avoid getting locked out and having to go through
* standalone mode, we refuse to disallow connections to the database
* we're currently connected to. Lockout can still happen with concurrent
* sessions but the likeliness of that is not high enough to worry about.
*/
if (!dballowconnections && dboid == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("cannot disallow connections for current database")));
/*
* Build an updated tuple, perusing the information just obtained
*/
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
MemSet(new_record_repl, false, sizeof(new_record_repl));
if (distemplate)
{
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(dbistemplate);
new_record_repl[Anum_pg_database_datistemplate - 1] = true;
}
if (dallowconnections)
{
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(dballowconnections);
new_record_repl[Anum_pg_database_datallowconn - 1] = true;
}
if (dconnlimit)
{
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record_repl[Anum_pg_database_datconnlimit - 1] = true;
}
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel), new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(rel, &tuple->t_self, newtuple);
InvokeObjectPostAlterHook(DatabaseRelationId,
HeapTupleGetOid(newtuple), 0);
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
heap_close(rel, NoLock);
return dboid;
}
/*
* ALTER DATABASE name SET ...
*/
Oid
AlterDatabaseSet(AlterDatabaseSetStmt *stmt)
{
Oid datid = get_database_oid(stmt->dbname, false);
/*
* Obtain a lock on the database and make sure it didn't go away in the
* meantime.
*/
shdepLockAndCheckObject(DatabaseRelationId, datid);
if (!pg_database_ownercheck(datid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
stmt->dbname);
AlterSetting(datid, InvalidOid, stmt->setstmt);
UnlockSharedObject(DatabaseRelationId, datid, 0, AccessShareLock);
return datid;
}
/*
* ALTER DATABASE name OWNER TO newowner
*/
ObjectAddress
AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
{
Oid db_id;
HeapTuple tuple;
Relation rel;
ScanKeyData scankey;
SysScanDesc scan;
Form_pg_database datForm;
ObjectAddress address;
/*
* Get the old tuple. We don't need a lock on the database per se,
* because we're not going to do anything that would mess up incoming
* connections.
*/
rel = heap_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
db_id = HeapTupleGetOid(tuple);
datForm = (Form_pg_database) GETSTRUCT(tuple);
/*
* If the new owner is the same as the existing owner, consider the
* command to have succeeded. This is to be consistent with other
* objects.
*/
if (datForm->datdba != newOwnerId)
{
Datum repl_val[Natts_pg_database];
bool repl_null[Natts_pg_database];
bool repl_repl[Natts_pg_database];
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* Otherwise, must be owner of the existing object */
if (!pg_database_ownercheck(HeapTupleGetOid(tuple), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/* Must be able to become new owner */
check_is_member_of_role(GetUserId(), newOwnerId);
/*
* must have createdb rights
*
* NOTE: This is different from other alter-owner checks in that the
* current user is checked for createdb privileges instead of the
* destination owner. This is consistent with the CREATE case for
* databases. Because superusers will always have this right, we need
* no special case for them.
*/
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to change owner of database")));
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
repl_repl[Anum_pg_database_datdba - 1] = true;
repl_val[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = heap_getattr(tuple,
Anum_pg_database_datacl,
RelationGetDescr(rel),
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
datForm->datdba, newOwnerId);
repl_repl[Anum_pg_database_datacl - 1] = true;
repl_val[Anum_pg_database_datacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel), repl_val, repl_null, repl_repl);
CatalogTupleUpdate(rel, &newtuple->t_self, newtuple);
heap_freetuple(newtuple);
/* Update owner dependency reference */
changeDependencyOnOwner(DatabaseRelationId, HeapTupleGetOid(tuple),
newOwnerId);
}
InvokeObjectPostAlterHook(DatabaseRelationId, HeapTupleGetOid(tuple), 0);
ObjectAddressSet(address, DatabaseRelationId, db_id);
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
heap_close(rel, NoLock);
return address;
}
/*
* Helper functions
*/
/*
* Look up info about the database named "name". If the database exists,
* obtain the specified lock type on it, fill in any of the remaining
* parameters that aren't NULL, and return true. If no such database,
* return false.
*/
static bool
get_db_info(const char *name, LOCKMODE lockmode,
Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP, TransactionId *dbFrozenXidP,
MultiXactId *dbMinMultiP,
Oid *dbTablespace, char **dbCollate, char **dbCtype)
{
bool result = false;
Relation relation;
AssertArg(name);
/* Caller may wish to grab a better lock on pg_database beforehand... */
relation = heap_open(DatabaseRelationId, AccessShareLock);
/*
* Loop covers the rare case where the database is renamed before we can
* lock it. We try again just in case we can find a new one of the same
* name.
*/
for (;;)
{
ScanKeyData scanKey;
SysScanDesc scan;
HeapTuple tuple;
Oid dbOid;
/*
* there's no syscache for database-indexed-by-name, so must do it the
* hard way
*/
ScanKeyInit(&scanKey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(name));
scan = systable_beginscan(relation, DatabaseNameIndexId, true,
NULL, 1, &scanKey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
{
/* definitely no database of that name */
systable_endscan(scan);
break;
}
dbOid = HeapTupleGetOid(tuple);
systable_endscan(scan);
/*
* Now that we have a database OID, we can try to lock the DB.
*/
if (lockmode != NoLock)
LockSharedObject(DatabaseRelationId, dbOid, 0, lockmode);
/*
* And now, re-fetch the tuple by OID. If it's still there and still
* the same name, we win; else, drop the lock and loop back to try
* again.
*/
tuple = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(dbOid));
if (HeapTupleIsValid(tuple))
{
Form_pg_database dbform = (Form_pg_database) GETSTRUCT(tuple);
if (strcmp(name, NameStr(dbform->datname)) == 0)
{
/* oid of the database */
if (dbIdP)
*dbIdP = dbOid;
/* oid of the owner */
if (ownerIdP)
*ownerIdP = dbform->datdba;
/* character encoding */
if (encodingP)
*encodingP = dbform->encoding;
/* allowed as template? */
if (dbIsTemplateP)
*dbIsTemplateP = dbform->datistemplate;
/* allowing connections? */
if (dbAllowConnP)
*dbAllowConnP = dbform->datallowconn;
/* last system OID used in database */
if (dbLastSysOidP)
*dbLastSysOidP = dbform->datlastsysoid;
/* limit of frozen XIDs */
if (dbFrozenXidP)
*dbFrozenXidP = dbform->datfrozenxid;
/* minimum MultixactId */
if (dbMinMultiP)
*dbMinMultiP = dbform->datminmxid;
/* default tablespace for this database */
if (dbTablespace)
*dbTablespace = dbform->dattablespace;
/* default locale settings for this database */
if (dbCollate)
*dbCollate = pstrdup(NameStr(dbform->datcollate));
if (dbCtype)
*dbCtype = pstrdup(NameStr(dbform->datctype));
ReleaseSysCache(tuple);
result = true;
break;
}
/* can only get here if it was just renamed */
ReleaseSysCache(tuple);
}
if (lockmode != NoLock)
UnlockSharedObject(DatabaseRelationId, dbOid, 0, lockmode);
}
heap_close(relation, AccessShareLock);
return result;
}
/* Check if current user has createdb privileges */
static bool
have_createdb_privilege(void)
{
bool result = false;
HeapTuple utup;
/* Superusers can always do everything */
if (superuser())
return true;
utup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(GetUserId()));
if (HeapTupleIsValid(utup))
{
result = ((Form_pg_authid) GETSTRUCT(utup))->rolcreatedb;
ReleaseSysCache(utup);
}
return result;
}
/*
* Remove tablespace directories
*
* We don't know what tablespaces db_id is using, so iterate through all
* tablespaces removing <tablespace>/db_id
*/
static void
remove_dbtablespaces(Oid db_id)
{
Relation rel;
HeapScanDesc scan;
HeapTuple tuple;
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Oid dsttablespace = HeapTupleGetOid(tuple);
char *dstpath;
struct stat st;
/* Don't mess with the global tablespace */
if (dsttablespace == GLOBALTABLESPACE_OID)
continue;
dstpath = GetDatabasePath(db_id, dsttablespace);
if (lstat(dstpath, &st) < 0 || !S_ISDIR(st.st_mode))
{
/* Assume we can ignore it */
pfree(dstpath);
continue;
}
if (!rmtree(dstpath, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dstpath)));
/* Record the filesystem change in XLOG */
{
xl_dbase_drop_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = dsttablespace;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_drop_rec));
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_DROP | XLR_SPECIAL_REL_UPDATE);
}
pfree(dstpath);
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
}
/*
* Check for existing files that conflict with a proposed new DB OID;
* return true if there are any
*
* If there were a subdirectory in any tablespace matching the proposed new
* OID, we'd get a create failure due to the duplicate name ... and then we'd
* try to remove that already-existing subdirectory during the cleanup in
* remove_dbtablespaces. Nuking existing files seems like a bad idea, so
* instead we make this extra check before settling on the OID of the new
* database. This exactly parallels what GetNewRelFileNode() does for table
* relfilenode values.
*/
static bool
check_db_file_conflict(Oid db_id)
{
bool result = false;
Relation rel;
HeapScanDesc scan;
HeapTuple tuple;
rel = heap_open(TableSpaceRelationId, AccessShareLock);
scan = heap_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Oid dsttablespace = HeapTupleGetOid(tuple);
char *dstpath;
struct stat st;
/* Don't mess with the global tablespace */
if (dsttablespace == GLOBALTABLESPACE_OID)
continue;
dstpath = GetDatabasePath(db_id, dsttablespace);
if (lstat(dstpath, &st) == 0)
{
/* Found a conflicting file (or directory, whatever) */
pfree(dstpath);
result = true;
break;
}
pfree(dstpath);
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
return result;
}
/*
* Issue a suitable errdetail message for a busy database
*/
static int
errdetail_busy_db(int notherbackends, int npreparedxacts)
{
if (notherbackends > 0 && npreparedxacts > 0)
/*
* We don't deal with singular versus plural here, since gettext
* doesn't support multiple plurals in one string.
*/
errdetail("There are %d other session(s) and %d prepared transaction(s) using the database.",
notherbackends, npreparedxacts);
else if (notherbackends > 0)
errdetail_plural("There is %d other session using the database.",
"There are %d other sessions using the database.",
notherbackends,
notherbackends);
else
errdetail_plural("There is %d prepared transaction using the database.",
"There are %d prepared transactions using the database.",
npreparedxacts,
npreparedxacts);
return 0; /* just to keep ereport macro happy */
}
/*
* get_database_oid - given a database name, look up the OID
*
* If missing_ok is false, throw an error if database name not found. If
* true, just return InvalidOid.
*/
Oid
get_database_oid(const char *dbname, bool missing_ok)
{
Relation pg_database;
ScanKeyData entry[1];
SysScanDesc scan;
HeapTuple dbtuple;
Oid oid;
/*
* There's no syscache for pg_database indexed by name, so we must look
* the hard way.
*/
pg_database = heap_open(DatabaseRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(pg_database, DatabaseNameIndexId, true,
NULL, 1, entry);
dbtuple = systable_getnext(scan);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(dbtuple))
oid = HeapTupleGetOid(dbtuple);
else
oid = InvalidOid;
systable_endscan(scan);
heap_close(pg_database, AccessShareLock);
if (!OidIsValid(oid) && !missing_ok)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
dbname)));
return oid;
}
/*
* get_database_name - given a database OID, look up the name
*
* Returns a palloc'd string, or NULL if no such database.
*/
char *
get_database_name(Oid dbid)
{
HeapTuple dbtuple;
char *result;
dbtuple = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(dbid));
if (HeapTupleIsValid(dbtuple))
{
result = pstrdup(NameStr(((Form_pg_database) GETSTRUCT(dbtuple))->datname));
ReleaseSysCache(dbtuple);
}
else
result = NULL;
return result;
}
/*
* DATABASE resource manager's routines
*/
void
dbase_redo(XLogReaderState *record)
{
uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
/* Backup blocks are not used in dbase records */
Assert(!XLogRecHasAnyBlockRefs(record));
if (info == XLOG_DBASE_CREATE)
{
xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) XLogRecGetData(record);
char *src_path;
char *dst_path;
struct stat st;
src_path = GetDatabasePath(xlrec->src_db_id, xlrec->src_tablespace_id);
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
/*
* Our theory for replaying a CREATE is to forcibly drop the target
* subdirectory if present, then re-copy the source data. This may be
* more work than needed, but it is simple to implement.
*/
if (stat(dst_path, &st) == 0 && S_ISDIR(st.st_mode))
{
if (!rmtree(dst_path, true))
/* If this failed, copydir() below is going to error. */
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dst_path)));
}
/*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy.
*/
FlushDatabaseBuffers(xlrec->src_db_id);
/*
* Copy this subdirectory to the new location
*
* We don't need to copy subdirectories
*/
copydir(src_path, dst_path, false);
}
else if (info == XLOG_DBASE_DROP)
{
xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) XLogRecGetData(record);
char *dst_path;
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
if (InHotStandby)
{
/*
* Lock database while we resolve conflicts to ensure that
* InitPostgres() cannot fully re-execute concurrently. This
* avoids backends re-connecting automatically to same database,
* which can happen in some cases.
*
* This will lock out walsenders trying to connect to db-specific
* slots for logical decoding too, so it's safe for us to drop
* slots.
*/
LockSharedObjectForSession(DatabaseRelationId, xlrec->db_id, 0, AccessExclusiveLock);
ResolveRecoveryConflictWithDatabase(xlrec->db_id);
}
/* Drop any database-specific replication slots */
ReplicationSlotsDropDBSlots(xlrec->db_id);
/* Drop pages for this database that are in the shared buffer cache */
DropDatabaseBuffers(xlrec->db_id);
/* Also, clean out any fsync requests that might be pending in md.c */
ForgetDatabaseFsyncRequests(xlrec->db_id);
/* Clean out the xlog relcache too */
XLogDropDatabase(xlrec->db_id);
/* And remove the physical files */
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dst_path)));
if (InHotStandby)
{
/*
* Release locks prior to commit. XXX There is a race condition
* here that may allow backends to reconnect, but the window for
* this is small because the gap between here and commit is mostly
* fairly small and it is unlikely that people will be dropping
* databases that we are trying to connect to anyway.
*/
UnlockSharedObjectForSession(DatabaseRelationId, xlrec->db_id, 0, AccessExclusiveLock);
}
}
else
elog(PANIC, "dbase_redo: unknown op code %u", info);
}
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