Add pg_upgrade --jobs parameter

Add pg_upgrade --jobs, which allows parallel dump/restore of databases,
which improves performance.

contrib/pg_upgrade/Makefile

@@ -5,7 +5,7 @@ PGAPPICON = win32
 
 PROGRAM  = pg_upgrade
 OBJS = check.o controldata.o dump.o exec.o file.o function.o info.o \
-       option.o page.o pg_upgrade.o relfilenode.o server.o \
+       option.o page.o parallel.o pg_upgrade.o relfilenode.o server.o \
        tablespace.o util.o version.o version_old_8_3.o $(WIN32RES)
 
 PG_CPPFLAGS  = -DFRONTEND -DDLSUFFIX=\"$(DLSUFFIX)\" -I$(srcdir) -I$(libpq_srcdir)

contrib/pg_upgrade/dump.c

@@ -33,18 +33,23 @@ generate_old_dump(void)
  	/* create per-db dump files */
 	for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
 	{
-		char 		file_name[MAXPGPATH];
+		char 		sql_file_name[MAXPGPATH], log_file_name[MAXPGPATH];
 		DbInfo     *old_db = &old_cluster.dbarr.dbs[dbnum];
 
 		pg_log(PG_STATUS, "%s", old_db->db_name);
-		snprintf(file_name, sizeof(file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+		snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+		snprintf(log_file_name, sizeof(log_file_name), DB_DUMP_LOG_FILE_MASK, old_db->db_oid);
 
-		exec_prog(RESTORE_LOG_FILE, NULL, true,
+		parallel_exec_prog(log_file_name, NULL,
 				  "\"%s/pg_dump\" %s --schema-only --binary-upgrade --format=custom %s --file=\"%s\" \"%s\"",
 				  new_cluster.bindir, cluster_conn_opts(&old_cluster),
-				  log_opts.verbose ? "--verbose" : "", file_name, old_db->db_name);
+				  log_opts.verbose ? "--verbose" : "", sql_file_name, old_db->db_name);
 	}
 
+	/* reap all children */
+	while (reap_child(true) == true)
+		;
+	            
 	end_progress_output();
 	check_ok();
 }

contrib/pg_upgrade/option.c

@@ -52,6 +52,7 @@ parseCommandLine(int argc, char *argv[])
 		{"check", no_argument, NULL, 'c'},
 		{"link", no_argument, NULL, 'k'},
 		{"retain", no_argument, NULL, 'r'},
+		{"jobs", required_argument, NULL, 'j'},
 		{"verbose", no_argument, NULL, 'v'},
 		{NULL, 0, NULL, 0}
 	};
@@ -101,7 +102,7 @@ parseCommandLine(int argc, char *argv[])
 	if ((log_opts.internal = fopen_priv(INTERNAL_LOG_FILE, "a")) == NULL)
 		pg_log(PG_FATAL, "cannot write to log file %s\n", INTERNAL_LOG_FILE);
 
-	while ((option = getopt_long(argc, argv, "d:D:b:B:cko:O:p:P:ru:v",
+	while ((option = getopt_long(argc, argv, "d:D:b:B:cj:ko:O:p:P:ru:v",
 								 long_options, &optindex)) != -1)
 	{
 		switch (option)
@@ -128,6 +129,10 @@ parseCommandLine(int argc, char *argv[])
 				new_cluster.pgconfig = pg_strdup(optarg);
 				break;
 
+			case 'j':
+				user_opts.jobs = atoi(optarg);
+				break;
+
 			case 'k':
 				user_opts.transfer_mode = TRANSFER_MODE_LINK;
 				break;
@@ -229,6 +234,7 @@ Options:\n\
   -c, --check                   check clusters only, don't change any data\n\
   -d, --old-datadir=OLDDATADIR  old cluster data directory\n\
   -D, --new-datadir=NEWDATADIR  new cluster data directory\n\
+  -j, --jobs                    number of simultaneous processes or threads to use\n\
   -k, --link                    link instead of copying files to new cluster\n\
   -o, --old-options=OPTIONS     old cluster options to pass to the server\n\
   -O, --new-options=OPTIONS     new cluster options to pass to the server\n\

contrib/pg_upgrade/parallel.c

@@ -0,0 +1,218 @@
+/*
+ *	parallel.c
+ *
+ *	multi-process support
+ *
+ *	Copyright (c) 2010-2012, PostgreSQL Global Development Group
+ *	contrib/pg_upgrade/parallel.c
+ */
+
+#include "postgres.h"
+
+#include "pg_upgrade.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#ifdef WIN32
+#include <io.h>
+#endif
+
+static int parallel_jobs;
+
+#ifdef WIN32
+/*
+ *	Array holding all active threads.  There can't be any gaps/zeros so
+ *	it can be passed to WaitForMultipleObjects().  We use two arrays
+ *	so the thread_handles array can be passed to WaitForMultipleObjects().
+ */
+HANDLE *thread_handles;
+
+typedef struct {
+	char log_file[MAXPGPATH];
+	char opt_log_file[MAXPGPATH];
+	char cmd[MAX_STRING];
+} thread_arg;
+
+thread_arg **thread_args;
+
+DWORD win32_exec_prog(thread_arg *args);
+
+#endif
+
+/*
+ *	parallel_exec_prog
+ *
+ *	This has the same API as exec_prog, except it does parallel execution,
+ *	and therefore must throw errors and doesn't return an error status.
+ */
+void
+parallel_exec_prog(const char *log_file, const char *opt_log_file,
+				   const char *fmt,...)
+{
+	va_list		args;
+	char		cmd[MAX_STRING];
+#ifndef WIN32
+	pid_t		child;
+#else
+	HANDLE		child;
+	thread_arg	*new_arg;
+#endif
+
+	va_start(args, fmt);
+	vsnprintf(cmd, sizeof(cmd), fmt, args);
+	va_end(args);
+
+	if (user_opts.jobs <= 1)
+		/* throw_error must be true to allow jobs */
+		exec_prog(log_file, opt_log_file, true, "%s", cmd);
+	else
+	{
+		/* parallel */
+
+		/* harvest any dead children */
+		while (reap_child(false) == true)
+			;
+
+		/* must we wait for a dead child? */
+		if (parallel_jobs >= user_opts.jobs)
+			reap_child(true);
+			
+		/* set this before we start the job */
+		parallel_jobs++;
+	
+		/* Ensure stdio state is quiesced before forking */
+		fflush(NULL);
+
+#ifndef WIN32
+		child = fork();
+		if (child == 0)
+			/* use _exit to skip atexit() functions */
+			_exit(!exec_prog(log_file, opt_log_file, true, "%s", cmd));
+		else if (child < 0)
+			/* fork failed */
+			pg_log(PG_FATAL, "could not create worker process: %s\n", strerror(errno));
+#else
+		if (thread_handles == NULL)
+		{
+			int i;
+
+			thread_handles = pg_malloc(user_opts.jobs * sizeof(HANDLE));
+			thread_args = pg_malloc(user_opts.jobs * sizeof(thread_arg *));
+
+			/*
+			 *	For safety and performance, we keep the args allocated during
+			 *	the entire life of the process, and we don't free the args
+			 *	in a thread different from the one that allocated it.
+			 */
+			for (i = 0; i < user_opts.jobs; i++)
+				thread_args[i] = pg_malloc(sizeof(thread_arg));
+		}
+
+		/* use first empty array element */
+		new_arg = thread_args[parallel_jobs-1];
+
+		/* Can only pass one pointer into the function, so use a struct */
+		strcpy(new_arg->log_file, log_file);
+		strcpy(new_arg->opt_log_file, opt_log_file);
+		strcpy(new_arg->cmd, cmd);
+
+		child = (HANDLE) _beginthreadex(NULL, 0, (void *) win32_exec_prog,
+						new_arg, 0, NULL);
+		if (child == 0)
+			pg_log(PG_FATAL, "could not create worker thread: %s\n", strerror(errno));
+
+		thread_handles[parallel_jobs-1] = child;
+#endif
+	}
+
+	return;
+}
+
+
+#ifdef WIN32
+DWORD
+win32_exec_prog(thread_arg *args)
+{
+	int ret;
+
+	ret = !exec_prog(args->log_file, args->opt_log_file, true, "%s", args->cmd);
+
+	/* terminates thread */
+	return ret;
+}
+#endif
+
+
+/*
+ *	collect status from a completed worker child
+ */
+bool
+reap_child(bool wait_for_child)
+{
+#ifndef WIN32
+	int work_status;
+	int ret;
+#else
+	int				thread_num;
+	DWORD			res;
+#endif
+
+	if (user_opts.jobs <= 1 || parallel_jobs == 0)
+		return false;
+
+#ifndef WIN32
+	ret = waitpid(-1, &work_status, wait_for_child ? 0 : WNOHANG);
+
+	/* no children or, for WNOHANG, no dead children */
+	if (ret <= 0 || !WIFEXITED(work_status))
+		return false;
+
+	if (WEXITSTATUS(work_status) != 0)
+		pg_log(PG_FATAL, "child worker exited abnormally: %s\n", strerror(errno));
+
+#else
+	/* wait for one to finish */
+	thread_num = WaitForMultipleObjects(parallel_jobs, thread_handles,
+					false, wait_for_child ? INFINITE : 0);
+
+	if (thread_num == WAIT_TIMEOUT || thread_num == WAIT_FAILED)
+		return false;
+
+	/* compute thread index in active_threads */
+	thread_num -= WAIT_OBJECT_0;
+	
+	/* get the result */
+	GetExitCodeThread(thread_handles[thread_num], &res);
+	if (res != 0)
+		pg_log(PG_FATAL, "child worker exited abnormally: %s\n", strerror(errno));
+
+	/* dispose of handle to stop leaks */
+	CloseHandle(thread_handles[thread_num]);
+
+	/*	Move last slot into dead child's position */
+	if (thread_num != parallel_jobs - 1)
+	{
+		thread_arg *tmp_args;
+	
+		thread_handles[thread_num] = thread_handles[parallel_jobs - 1];
+
+		/*
+		 *	We must swap the arg struct pointers because the thread we
+		 *	just moved is active, and we must make sure it is not
+		 *	reused by the next created thread.  Instead, the new thread
+		 *	will use the arg struct of the thread that just died.
+		 */
+		tmp_args = thread_args[thread_num];
+		thread_args[thread_num] = thread_args[parallel_jobs - 1];
+		thread_args[parallel_jobs - 1] = tmp_args;
+	}
+#endif
+
+	/* do this after job has been removed */
+	parallel_jobs--;
+
+	return true;
+}

contrib/pg_upgrade/pg_upgrade.c

@@ -61,7 +61,6 @@ char	   *output_files[] = {
 	/* unique file for pg_ctl start */
 	SERVER_START_LOG_FILE,
 #endif
-	RESTORE_LOG_FILE,
 	UTILITY_LOG_FILE,
 	INTERNAL_LOG_FILE,
 	NULL
@@ -270,7 +269,7 @@ prepare_new_databases(void)
 	 * support functions in template1 but pg_dumpall creates database using
 	 * the template0 template.
 	 */
-	exec_prog(RESTORE_LOG_FILE, NULL, true,
+	exec_prog(UTILITY_LOG_FILE, NULL, true,
 			  "\"%s/psql\" " EXEC_PSQL_ARGS " %s -f \"%s\"",
 			  new_cluster.bindir, cluster_conn_opts(&new_cluster),
 			  GLOBALS_DUMP_FILE);
@@ -307,22 +306,28 @@ create_new_objects(void)
 
 	for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
 	{
-		char file_name[MAXPGPATH];
+		char sql_file_name[MAXPGPATH], log_file_name[MAXPGPATH];
 		DbInfo     *old_db = &old_cluster.dbarr.dbs[dbnum];
 
 		pg_log(PG_STATUS, "%s", old_db->db_name);
-		snprintf(file_name, sizeof(file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+		snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+		snprintf(log_file_name, sizeof(log_file_name), DB_DUMP_LOG_FILE_MASK, old_db->db_oid);
 
 		/*
 		 *	Using pg_restore --single-transaction is faster than other
 		 *	methods, like --jobs.  pg_dump only produces its output at the
 		 *	end, so there is little parallelism using the pipe.
 		 */
-		exec_prog(RESTORE_LOG_FILE, NULL, true,
+		parallel_exec_prog(log_file_name, NULL,
 				  "\"%s/pg_restore\" %s --exit-on-error --single-transaction --verbose --dbname \"%s\" \"%s\"",
 				  new_cluster.bindir, cluster_conn_opts(&new_cluster),
-				  old_db->db_name, file_name);
+				  old_db->db_name, sql_file_name);
 	}
+
+	/* reap all children */
+	while (reap_child(true) == true)
+		;
+
 	end_progress_output();
 	check_ok();
 
@@ -494,11 +499,14 @@ cleanup(void)
 		if (old_cluster.dbarr.dbs)
 			for (dbnum = 0; dbnum < old_cluster.dbarr.ndbs; dbnum++)
 			{
-				char file_name[MAXPGPATH];
+				char sql_file_name[MAXPGPATH], log_file_name[MAXPGPATH];
 				DbInfo     *old_db = &old_cluster.dbarr.dbs[dbnum];
 
-				snprintf(file_name, sizeof(file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
-				unlink(file_name);
+				snprintf(sql_file_name, sizeof(sql_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+				unlink(sql_file_name);
+
+				snprintf(log_file_name, sizeof(log_file_name), DB_DUMP_FILE_MASK, old_db->db_oid);
+				unlink(log_file_name);
 			}
 	}
 }

contrib/pg_upgrade/pg_upgrade.h

@@ -32,8 +32,8 @@
 #define GLOBALS_DUMP_FILE	"pg_upgrade_dump_globals.sql"
 #define DB_DUMP_FILE_MASK	"pg_upgrade_dump_%u.custom"
 
+#define DB_DUMP_LOG_FILE_MASK	"pg_upgrade_dump_%u.log"
 #define SERVER_LOG_FILE		"pg_upgrade_server.log"
-#define RESTORE_LOG_FILE	"pg_upgrade_restore.log"
 #define UTILITY_LOG_FILE	"pg_upgrade_utility.log"
 #define INTERNAL_LOG_FILE	"pg_upgrade_internal.log"
 
@@ -264,6 +264,7 @@ typedef struct
 	bool		check;			/* TRUE -> ask user for permission to make
 								 * changes */
 	transferMode transfer_mode; /* copy files or link them? */
+	int			jobs;
 } UserOpts;
 
 
@@ -461,3 +462,11 @@ void		old_8_3_invalidate_hash_gin_indexes(ClusterInfo *cluster, bool check_mode)
 void old_8_3_invalidate_bpchar_pattern_ops_indexes(ClusterInfo *cluster,
 											  bool check_mode);
 char	   *old_8_3_create_sequence_script(ClusterInfo *cluster);
+
+/* parallel.c */
+void parallel_exec_prog(const char *log_file, const char *opt_log_file,
+		  const char *fmt,...)
+__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
+
+bool reap_child(bool wait_for_child);
+

doc/src/sgml/pgupgrade.sgml

@@ -112,6 +112,13 @@
       variable <envar>PGDATANEW</></para></listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>-j</option></term>
+      <term><option>--jobs</option></term>
+      <listitem><para>number of simultaneous processes or threads to use
+      </para></listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-k</option></term>
       <term><option>--link</option></term>
@@ -331,10 +338,15 @@ NET STOP pgsql-8.3  (<productname>PostgreSQL</> 8.3 and older used a different s
      requires that the old and new cluster data directories be in the
      same file system.  See <literal>pg_upgrade --help</> for a full
      list of options.
-   </para>
+    </para>
 
-   <para>
-   </para>
+    <para>
+     The <option>--jobs</> option allows multiple CPU cores to be used
+     to dump and reload database schemas in parallel;  a good place to
+     start is the number of CPU cores on the server.  This option can
+     dramatically reduce the time to upgrade a multi-database server
+     running on a multiprocessor machine.
+    </para>
 
     <para>
      For Windows users, you must be logged into an administrative account, and