Add functions pg_start_backup, pg_stop_backup to create backup label

and history files as per recent discussion.  While at it, remove
pg_terminate_backend, since we have decided we do not have time during
this release cycle to address the reliability concerns it creates.
Split the 'Miscellaneous Functions' documentation section into
'System Information Functions' and 'System Administration Functions',
which hopefully will draw the eyes of those looking for such things.

1 files changed, 51 insertions, 31 deletions

diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0cc315c6205..8bf989a8658 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.35 2004/07/02 18:59:22 joe Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.36 2004/08/03 20:32:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,6 +27,8 @@
 #include "catalog/pg_type.h"
 #include "catalog/pg_tablespace.h"
 
+#define atooid(x)  ((Oid) strtoul((x), NULL, 10))
+
 
 /*
  * Check if data is Null
@@ -67,8 +69,7 @@ current_database(PG_FUNCTION_ARGS)
 
 
 /*
- * Functions to terminate a backend or cancel a query running on
- * a different backend.
+ * Functions to send signals to other backends.
  */
 
 static int pg_signal_backend(int pid, int sig) 
@@ -76,14 +77,16 @@ static int pg_signal_backend(int pid, int sig)
 	if (!superuser()) 
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-				 (errmsg("only superuser can signal other backends"))));
+				 (errmsg("must be superuser to signal other server processes"))));
 	
 	if (!IsBackendPid(pid))
 	{
-		/* This is just a warning so a loop-through-resultset will not abort
-		 * if one backend terminated on it's own during the run */
+		/*
+		 * This is just a warning so a loop-through-resultset will not abort
+		 * if one backend terminated on it's own during the run
+		 */
 		ereport(WARNING,
-				(errmsg("pid %i is not a postgresql backend",pid)));
+				(errmsg("PID %d is not a PostgreSQL server process", pid)));
 		return 0;
 	}
 
@@ -91,24 +94,32 @@ static int pg_signal_backend(int pid, int sig)
 	{
 		/* Again, just a warning to allow loops */
 		ereport(WARNING,
-				(errmsg("failed to send signal to backend %i: %m",pid)));
+				(errmsg("could not send signal to process %d: %m",pid)));
 		return 0;
 	}
 	return 1;
 }
 
 Datum
-pg_terminate_backend(PG_FUNCTION_ARGS)
+pg_cancel_backend(PG_FUNCTION_ARGS)
 {
-	PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGTERM));
+	PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGINT));
 }
 
+#ifdef NOT_USED
+
+/* Disabled in 8.0 due to reliability concerns; FIXME someday */
+
 Datum
-pg_cancel_backend(PG_FUNCTION_ARGS)
+pg_terminate_backend(PG_FUNCTION_ARGS)
 {
-	PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGINT));
+	PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0),SIGTERM));
 }
 
+#endif
+
+
+/* Function to find out which databases make use of a tablespace */
 
 typedef struct 
 {
@@ -140,9 +151,8 @@ Datum pg_tablespace_databases(PG_FUNCTION_ARGS)
 		if (tablespaceOid == GLOBALTABLESPACE_OID)
 		{
 			fctx->dirdesc = NULL;
-			ereport(NOTICE,
-					(errcode(ERRCODE_WARNING),
-					 errmsg("global tablespace never has databases.")));
+			ereport(WARNING,
+					(errmsg("global tablespace never has databases")));
 		}
 		else
 		{
@@ -154,10 +164,17 @@ Datum pg_tablespace_databases(PG_FUNCTION_ARGS)
 		
 			fctx->dirdesc = AllocateDir(fctx->location);
 
-			if (!fctx->dirdesc)  /* not a tablespace */
-				ereport(NOTICE,
-						(errcode(ERRCODE_WARNING),
-						 errmsg("%d is no tablespace oid.", tablespaceOid)));
+			if (!fctx->dirdesc)
+			{
+				/* the only expected error is ENOENT */
+				if (errno != ENOENT)
+					ereport(ERROR,
+							(errcode_for_file_access(),
+							 errmsg("could not open directory \"%s\": %m",
+									fctx->location)));
+				ereport(WARNING,
+						(errmsg("%u is not a tablespace oid", tablespaceOid)));
+			}
 		}
 		funcctx->user_fctx = fctx;
 		MemoryContextSwitchTo(oldcontext);
@@ -174,27 +191,30 @@ Datum pg_tablespace_databases(PG_FUNCTION_ARGS)
 		char *subdir;
 		DIR *dirdesc;
 
-		Oid datOid = atol(de->d_name);
+		Oid datOid = atooid(de->d_name);
+		/* this test skips . and .., but is awfully weak */
 		if (!datOid)
 			continue;
 
+		/* if database subdir is empty, don't report tablespace as used */
+
 		/* size = path length + dir sep char + file name + terminator */
 		subdir = palloc(strlen(fctx->location) + 1 + strlen(de->d_name) + 1);
 		sprintf(subdir, "%s/%s", fctx->location, de->d_name);
 		dirdesc = AllocateDir(subdir);
-		if (dirdesc)
-		{
-			while ((de = readdir(dirdesc)) != 0)
-			{
-				if (strcmp(de->d_name, ".") && strcmp(de->d_name, ".."))
-					break;
-			}
-			pfree(subdir);
-			FreeDir(dirdesc);
+		pfree(subdir);
+		if (!dirdesc)
+			continue;			/* XXX more sloppiness */
 
-			if (!de)   /* database subdir is empty; don't report tablespace as used */
-				continue;
+		while ((de = readdir(dirdesc)) != 0)
+		{
+			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0)
+				break;
 		}
+		FreeDir(dirdesc);
+
+		if (!de)
+			continue;			/* indeed, nothing in it */
 
 		SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(datOid));
 	}