diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index 8b380157eef1518d1bd68812c13c9d4c1294fc79..f4bfa5cf6dbe77597a12f9245325fecbcef2cbe1 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -13,7 +13,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.209 2008/05/12 00:00:47 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.210 2008/08/04 18:03:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -73,6 +73,7 @@ static bool get_db_info(const char *name, LOCKMODE lockmode,
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);
/*
@@ -110,6 +111,8 @@ createdb(const CreatedbStmt *stmt)
int encoding = -1;
int dbconnlimit = -1;
int ctype_encoding;
+ int notherbackends;
+ int npreparedxacts;
createdb_failure_params fparms;
/* Extract options from the statement node tree */
@@ -385,11 +388,12 @@ createdb(const CreatedbStmt *stmt)
* potential waiting; we may as well throw an error first if we're gonna
* throw one.
*/
- if (CheckOtherDBBackends(src_dboid))
+ if (CountOtherDBBackends(src_dboid, ¬herbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("source database \"%s\" is being accessed by other users",
- dbtemplate)));
+ dbtemplate),
+ errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Select an OID for the new database, checking that it doesn't have a
@@ -612,6 +616,8 @@ dropdb(const char *dbname, bool missing_ok)
bool db_istemplate;
Relation pgdbrel;
HeapTuple tup;
+ int notherbackends;
+ int npreparedxacts;
/*
* Look up the target database's OID, and get exclusive lock on it. We
@@ -671,11 +677,12 @@ dropdb(const char *dbname, bool missing_ok)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
- if (CheckOtherDBBackends(db_id))
+ if (CountOtherDBBackends(db_id, ¬herbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
- dbname)));
+ dbname),
+ errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Remove the database's tuple from pg_database.
@@ -764,6 +771,8 @@ RenameDatabase(const char *oldname, const char *newname)
Oid db_id;
HeapTuple newtup;
Relation rel;
+ int notherbackends;
+ int npreparedxacts;
/*
* Look up the target database's OID, and get exclusive lock on it. We
@@ -814,11 +823,12 @@ RenameDatabase(const char *oldname, const char *newname)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
- if (CheckOtherDBBackends(db_id))
+ if (CountOtherDBBackends(db_id, ¬herbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
- oldname)));
+ oldname),
+ errdetail_busy_db(notherbackends, npreparedxacts)));
/* rename */
newtup = SearchSysCacheCopy(DATABASEOID,
@@ -1400,6 +1410,29 @@ check_db_file_conflict(Oid db_id)
return result;
}
+/*
+ * Issue a suitable errdetail message for a busy database
+ */
+static int
+errdetail_busy_db(int notherbackends, int npreparedxacts)
+{
+ /*
+ * We don't worry about singular versus plural here, since the English
+ * rules for that don't translate very well. But we can at least avoid
+ * the case of zero items.
+ */
+ if (notherbackends > 0 && npreparedxacts > 0)
+ errdetail("There are %d other session(s) and %d prepared transaction(s) using the database.",
+ notherbackends, npreparedxacts);
+ else if (notherbackends > 0)
+ errdetail("There are %d other session(s) using the database.",
+ notherbackends);
+ else
+ errdetail("There are %d prepared transaction(s) using the database.",
+ npreparedxacts);
+ return 0; /* just to keep ereport macro happy */
+}
+
/*
* get_database_oid - given a database name, look up the OID
*
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 0286809d1c4fba135037e2b380d6fca035a1accf..42ed5865d9c80408c90201c3044afba758ccad43 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -23,7 +23,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.45 2008/07/11 02:10:13 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.46 2008/08/04 18:03:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1177,7 +1177,7 @@ CountUserBackends(Oid roleid)
}
/*
- * CheckOtherDBBackends -- check for other backends running in the given DB
+ * CountOtherDBBackends -- check for other backends running in the given DB
*
* If there are other backends in the DB, we will wait a maximum of 5 seconds
* for them to exit. Autovacuum backends are encouraged to exit early by
@@ -1187,6 +1187,8 @@ CountUserBackends(Oid roleid)
* check whether the current backend uses the given DB, if it's important.
*
* Returns TRUE if there are (still) other backends in the DB, FALSE if not.
+ * Also, *nbackends and *nprepared are set to the number of other backends
+ * and prepared transactions in the DB, respectively.
*
* This function is used to interlock DROP DATABASE and related commands
* against there being any active backends in the target DB --- dropping the
@@ -1198,19 +1200,24 @@ CountUserBackends(Oid roleid)
* indefinitely.
*/
bool
-CheckOtherDBBackends(Oid databaseId)
+CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared)
{
ProcArrayStruct *arrayP = procArray;
+#define MAXAUTOVACPIDS 10 /* max autovacs to SIGTERM per iteration */
+ int autovac_pids[MAXAUTOVACPIDS];
int tries;
/* 50 tries with 100ms sleep between tries makes 5 sec total wait */
for (tries = 0; tries < 50; tries++)
{
+ int nautovacs = 0;
bool found = false;
int index;
CHECK_FOR_INTERRUPTS();
+ *nbackends = *nprepared = 0;
+
LWLockAcquire(ProcArrayLock, LW_SHARED);
for (index = 0; index < arrayP->numProcs; index++)
@@ -1224,38 +1231,32 @@ CheckOtherDBBackends(Oid databaseId)
found = true;
- if (proc->vacuumFlags & PROC_IS_AUTOVACUUM)
- {
- /* an autovacuum --- send it SIGTERM before sleeping */
- int autopid = proc->pid;
-
- /*
- * It's a bit awkward to release ProcArrayLock within the
- * loop, but we'd probably better do so before issuing kill().
- * We have no idea what might block kill() inside the
- * kernel...
- */
- LWLockRelease(ProcArrayLock);
-
- (void) kill(autopid, SIGTERM); /* ignore any error */
-
- break;
- }
+ if (proc->pid == 0)
+ (*nprepared)++;
else
{
- LWLockRelease(ProcArrayLock);
- break;
+ (*nbackends)++;
+ if ((proc->vacuumFlags & PROC_IS_AUTOVACUUM) &&
+ nautovacs < MAXAUTOVACPIDS)
+ autovac_pids[nautovacs++] = proc->pid;
}
}
- /* if found is set, we released the lock within the loop body */
+ LWLockRelease(ProcArrayLock);
+
if (!found)
- {
- LWLockRelease(ProcArrayLock);
return false; /* no conflicting backends, so done */
- }
- /* else sleep and try again */
+ /*
+ * Send SIGTERM to any conflicting autovacuums before sleeping.
+ * We postpone this step until after the loop because we don't
+ * want to hold ProcArrayLock while issuing kill().
+ * We have no idea what might block kill() inside the kernel...
+ */
+ for (index = 0; index < nautovacs; index++)
+ (void) kill(autovac_pids[index], SIGTERM); /* ignore any error */
+
+ /* sleep, then try again */
pg_usleep(100 * 1000L); /* 100ms */
}
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index ea0aa999441843a2afd6c29ff1630cbb113a2ac6..4f412c5f1ba0d815d4a0f5f7efbfa84c385904d7 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.22 2008/05/12 20:02:02 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.23 2008/08/04 18:03:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -44,7 +44,8 @@ extern VirtualTransactionId *GetCurrentVirtualXIDs(TransactionId limitXmin,
extern int CountActiveBackends(void);
extern int CountDBBackends(Oid databaseid);
extern int CountUserBackends(Oid roleid);
-extern bool CheckOtherDBBackends(Oid databaseId);
+extern bool CountOtherDBBackends(Oid databaseId,
+ int *nbackends, int *nprepared);
extern void XidCacheRemoveRunningXids(TransactionId xid,
int nxids, const TransactionId *xids,