Released as 20160101 ('20160101alpha')

README

@@ -40,9 +40,9 @@ document.
 
 Full installation of GNU Parallel is as simple as:
 
-    wget http://ftpmirror.gnu.org/parallel/parallel-20151222.tar.bz2
+    wget http://ftpmirror.gnu.org/parallel/parallel-20160101.tar.bz2
-    bzip2 -dc parallel-20151222.tar.bz2 | tar xvf -
+    bzip2 -dc parallel-20160101.tar.bz2 | tar xvf -
-    cd parallel-20151222
+    cd parallel-20160101
     ./configure && make && sudo make install
 
 
@@ -51,9 +51,9 @@ Full installation of GNU Parallel is as simple as:
 If you are not root you can add ~/bin to your path and install in
 ~/bin and ~/share:
 
-    wget http://ftpmirror.gnu.org/parallel/parallel-20151222.tar.bz2
+    wget http://ftpmirror.gnu.org/parallel/parallel-20160101.tar.bz2
-    bzip2 -dc parallel-20151222.tar.bz2 | tar xvf -
+    bzip2 -dc parallel-20160101.tar.bz2 | tar xvf -
-    cd parallel-20151222
+    cd parallel-20160101
     ./configure --prefix=$HOME && make && make install
 
 Or if your system lacks 'make' you can simply copy src/parallel

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for parallel 20151222.
+# Generated by GNU Autoconf 2.69 for parallel 20160101.
 #
 # Report bugs to <bug-parallel@gnu.org>.
 #
@@ -579,8 +579,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='parallel'
 PACKAGE_TARNAME='parallel'
-PACKAGE_VERSION='20151222'
+PACKAGE_VERSION='20160101'
-PACKAGE_STRING='parallel 20151222'
+PACKAGE_STRING='parallel 20160101'
 PACKAGE_BUGREPORT='bug-parallel@gnu.org'
 PACKAGE_URL=''
 
@@ -1203,7 +1203,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures parallel 20151222 to adapt to many kinds of systems.
+\`configure' configures parallel 20160101 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1269,7 +1269,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of parallel 20151222:";;
+     short | recursive ) echo "Configuration of parallel 20160101:";;
    esac
   cat <<\_ACEOF
 
@@ -1345,7 +1345,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-parallel configure 20151222
+parallel configure 20160101
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -1362,7 +1362,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by parallel $as_me 20151222, which was
+It was created by parallel $as_me 20160101, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2225,7 +2225,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='parallel'
- VERSION='20151222'
+ VERSION='20160101'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -2867,7 +2867,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by parallel $as_me 20151222, which was
+This file was extended by parallel $as_me 20160101, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -2929,7 +2929,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-parallel config.status 20151222
+parallel config.status 20160101
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT([parallel], [20151222], [bug-parallel@gnu.org])
+AC_INIT([parallel], [20160101], [bug-parallel@gnu.org])
 AM_INIT_AUTOMAKE([-Wall -Werror foreign])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([

doc/release_new_version

@@ -212,9 +212,9 @@ cc:Tim Cuthbertson <tim3d.junk@gmail.com>,
    Ryoichiro Suzuki <ryoichiro.suzuki@gmail.com>,
    Jesse Alama <jesse.alama@gmail.com>
 
-Subject: GNU Parallel 20151222 ('') released <<[stable]>>
+Subject: GNU Parallel 20160122 ('') released <<[stable]>>
 
-GNU Parallel 20151222 ('') <<[stable]>> has been released. It is available for download at: http://ftp.gnu.org/gnu/parallel/
+GNU Parallel 20160122 ('') <<[stable]>> has been released. It is available for download at: http://ftp.gnu.org/gnu/parallel/
 
 <<No new functionality was introduced so this is a good candidate for a stable release.>>
 
@@ -227,11 +227,19 @@ Haiku of the month:
 
 New in this release:
 
-* --transfer is now an alias for --transferfile {}.
+* --sql DBURL uses DBURL as storage for jobs and output. It does not run any jobs so it requires at least one --sqlworker. DBURL must point to a table.
 
-* --transferfile works like --transfer, but takes an argument like --return. This makes it possible to combine transferring files with multiple input sources: parallel -S server --tf {1} wc {2} {1} ::: * ::: -l -w -c
+* --sqlworker DBURL gets jobs from DBURL and stores the result back to DBURL.
 
-* total_jobs() can now be used in {= =}: parallel echo job {#} of '{= $_=total_jobs() =}' ::: {1..50}
+* --sqlandworker is a shorthand for --sql and --sqlworker.
+
+* --sqlworker requires the output of a single job to fit in memory.
+
+* --results now also saves a file called 'seq' containing the sequence number.
+
+* If $PARALLEL_ENV is a file, then that file will be read into $PARALLEL_ENV.
+
+* man parallel_tutorial has been given an overhaul.
 
 * << kontakt GNU Parallel was used (unfortunately without citation) in: Instrumentation and Trace Analysis for Ad-hoc Python Workflows in Cloud Environments http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7214035>>
 
@@ -249,17 +257,13 @@ for Big Data Applications https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumb
 
 * <<Citation needed: Introspecting for RSA Key Material to Assist Intrusion Detection http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=7331177&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D7331177>>
 
-* GNU Parallel was cited in: Evolution and Learning in Heterogeneous Environments http://research.gold.ac.uk/15078/1/COM_thesis_JonesD_2015.pdf
+* GNU Parallel is used in LAST: http://last.cbrc.jp/
 
-* GNU Parallel was cited in: Contrasting genetic architectures of schizophrenia and other complex diseases using fast variance-components analysis http://www.nature.com/ng/journal/v47/n12/full/ng.3431.html
+* GNU Parallel was cited in: Possum - A Framework for Three-Dimensional Reconstruction of Brain Images rfom Serial Sections http://link.springer.com/article/10.1007/s12021-015-9286-1
 
-* GNU Parallel was cited in: Efficient Retrieval of Key Material for Inspecting Potentially Malicious Traffic in the Cloud http://www.cs.bham.ac.uk/~bxb/Papres/2015.1.pdf 
+* GNU Parallel was used in: Mission Impossible: you have 1 minute to analyze the Ebola Genome https://www.biostars.org/p/119397
 
-* GNU Parallel was cited in: Achieving Consistent Doppler Measurements from SDO/HMI Vector Field Inversions http://arxiv.org/pdf/1511.06500.pdf
+* Distributed Log Search Using GNU Parallel http://blog.codehate.com/post/134320079974/distributed-log-search-using-gnu-parallel
-
-* Flo uses GNU Parallel: https://github.com/wurmlab/flo
-
-* 使用 GNU parallel 來平行運算http://mutolisp.logdown.com/posts/316959-using-gnu-parallel-to-parallel-computing
 
 * Bug fixes and man page updates.
 

src/Makefile.in

@@ -78,7 +78,7 @@ NORMAL_UNINSTALL = :
 PRE_UNINSTALL = :
 POST_UNINSTALL = :
 subdir = src
-DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/Makefile.am README
+DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/Makefile.am
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \

src/niceload

@@ -24,7 +24,7 @@
 use strict;
 use Getopt::Long;
 $Global::progname="niceload";
-$Global::version = 20151222;
+$Global::version = 20160101;
 Getopt::Long::Configure("bundling","require_order");
 get_options_from_array(\@ARGV) || die_usage();
 if($opt::version) {

src/parallel

@@ -59,6 +59,15 @@ if($opt::pipepart) {
 	@input_source_fh = (*STDIN);
     }
 }
+if($opt::sql) {
+    # Create SQL table to hold joblog + output
+    $Global::sql->create_table($#input_source_fh+1);
+    if($opt::sqlworker) {
+	# Start a real --sqlworker in the background later
+	$Global::sqlworker = 1;
+	$opt::sqlworker = undef;
+    }
+}
 
 if($opt::skip_first_line) {
     # Skip the first line for the first file handle
@@ -751,6 +760,9 @@ sub options_hash {
 	 "m" => \$opt::m,
 	 "X" => \$opt::X,
 	 "v" => \@opt::v,
+	 "sql=s" => \$opt::sql,
+	 "sqlworker=s" => \$opt::sqlworker,
+	 "sqlandworker=s" => \$opt::sqlandworker,
 	 "joblog=s" => \$opt::joblog,
 	 "results|result|res=s" => \$opt::results,
 	 "resume" => \$opt::resume,
@@ -960,6 +972,7 @@ sub parse_options {
     if(defined $opt::tmpdir) { $ENV{'TMPDIR'} = $opt::tmpdir; }
     $opt::nice ||= 0;
     if(defined $opt::help) { die_usage(); }
+    if(defined $opt::sqlandworker) { $opt::sql = $opt::sqlworker = $opt::sqlandworker; }
     if(defined $opt::colsep) { $Global::trim = 'lr'; }
     if(defined $opt::header) { $opt::colsep = defined $opt::colsep ? $opt::colsep : "\t"; }
     if(defined $opt::trim) { $Global::trim = $opt::trim; }
@@ -1108,6 +1121,7 @@ sub parse_options {
         $opt::jobs = "100%";
     }
     open_joblog();
+    ($opt::sql or $opt::sqlworker) and $Global::sql = SQL->new($opt::sql || $opt::sqlworker);
 }
 
 sub check_invalid_option_combinations {
@@ -1162,7 +1176,7 @@ sub check_invalid_option_combinations {
 
 sub init_globals {
     # Defaults:
-    $Global::version = 20151222;
+    $Global::version = 20160101;
     $Global::progname = 'parallel';
     $Global::infinity = 2**31;
     $Global::debug = 0;
@@ -1595,6 +1609,7 @@ sub read_options {
 
     Getopt::Long::Configure("bundling","require_order");
     my @ARGV_copy = @ARGV;
+    my @ARGV_orig = @ARGV;
     # Check if there is a --profile to set @opt::profile
     get_options_from_array(\@ARGV_copy,"profile|J=s","plain") || die_usage();
     my @ARGV_profile = ();
@@ -1644,12 +1659,29 @@ sub read_options {
     get_options_from_array(\@ARGV_profile) || die_usage();
     get_options_from_array(\@ARGV_env) || die_usage();
     get_options_from_array(\@ARGV) || die_usage();
-
+    # What were the options given on the command line?
+    # Used to start --sqlworker
+    my $ai = arrayindex(\@ARGV_orig, \@ARGV);
+    @Global::options_in_argv = @ARGV_orig[0..$ai-1];
     # Prepend non-options to @ARGV (such as commands like 'nice')
     unshift @ARGV, @ARGV_profile, @ARGV_env;
     return @ARGV;
 }
 
+sub arrayindex {
+    # Similar to Perl's index function, but for arrays
+    # Input:
+    #   $arr_ref1 = ref to @array1 to search in
+    #   $arr_ref2 = ref to @array2 to search for
+    my ($arr_ref1,$arr_ref2) = @_;
+    my $array1_as_string = join "", map { "\257\257".$_ } @$arr_ref1;
+    my $array2_as_string = join "", map { "\257\257".$_ } @$arr_ref2;
+    my $i = index($array1_as_string,$array2_as_string,0);
+    if($i == -1) { return -1 }
+    my @before = split /\257\257/, substr($array1_as_string,0,$i);
+    return $#before;
+}
+
 sub read_args_from_command_line {
     # Arguments given on the command line after:
     #   ::: ($Global::arg_sep)
@@ -2322,9 +2354,27 @@ sub drain_job_queue {
 		::warning("There are no job slots available. Increase --jobs.");
 	    }
         }
+	while($opt::sql and not $Global::sql->finished()) {
+	    # SQL master
+	    $sleep = ::reap_usleep($sleep);
+	    if($Global::sqlworker) {
+		# Start an SQL worker as we are now sure there is work to do
+		$Global::sqlworker = 0;
+		if(fork()) {
+		    # skip
+		} else {
+		    # Replace --sql/--sqlandworker with --sqlworker
+		    my @ARGV = map { s/^--sql(andworker)?$/--sqlworker/; $_ } @Global::options_in_argv;
+		    # exec the --sqlworker
+		    exec($0,::shell_quote(@ARGV),@command);
+		}
+	    }
+	}
     } while ($Global::total_running > 0
 	     or
-	     not $Global::start_no_new_jobs and not $Global::JobQueue->empty());
+	     not $Global::start_no_new_jobs and not $Global::JobQueue->empty()
+	     or
+	     $opt::sql and not $Global::sql->finished());
     if($opt::progress) {
 	my %progress = progress();
 	::status("\r", $progress{'status'}, "\n");
@@ -3291,6 +3341,8 @@ sub reaper {
     my $stiff;
     my @pids_reaped;
     debug("run", "Reaper ");
+    # For efficiency surround with BEGIN/COMMIT when using $opt::sql
+    $opt::sql and $Global::sql->run("BEGIN;");
     while (($stiff = waitpid(-1, &WNOHANG)) > 0) {
 	# $stiff = pid of dead process
 	push(@pids_reaped,$stiff);
@@ -3348,6 +3400,7 @@ sub reaper {
 	    ::status("\r",$progress{'status'});
 	}
     }
+    $opt::sql and $Global::sql->run("COMMIT;");
     debug("run", "done ");
     return @pids_reaped;
 }
@@ -3741,6 +3794,13 @@ sub undef_as_empty {
     return $a ? $a : "";
 }
 
+sub undef_if_empty {
+    if(defined($_[0]) and $_[0] eq "") {
+	return undef;
+    }
+    return $_[0];
+}
+
 sub multiply_binary_prefix {
     # Evalualte numbers with binary prefix
     # Ki=2^10, Mi=2^20, Gi=2^30, Ti=2^40, Pi=2^50, Ei=2^70, Zi=2^80, Yi=2^80
@@ -6092,6 +6152,15 @@ sub openoutputfiles {
 	    $dir = $opt::results."/".$args_as_dirname;
 	    File::Path::mkpath($dir);
 	}
+	# prefix/name1/val1/name2/val2/seq
+	my $seqname = "$dir/seq";
+	my $seqfhw;
+	if(not open($seqfhw, "+>", $seqname)) {
+	    ::error("Cannot write to `$seqname'.");
+	    ::wait_and_exit(255);
+	}
+	print $seqfhw $self->seq();
+	close $seqfhw;
 	# prefix/name1/val1/name2/val2/stdout
 	$outname = "$dir/stdout";
 	if(not open($outfhw, "+>", $outname)) {
@@ -6106,6 +6175,13 @@ sub openoutputfiles {
 	}
 	$self->set_fh(1,"unlink","");
 	$self->set_fh(2,"unlink","");
+	if($opt::sqlworker) {
+	    # Save the filenames in SQL table
+	    $Global::sql->update("SET Stdout = ? WHERE Seq = ".$self->seq(),
+				 $outname);
+	    $Global::sql->update("SET Stderr = ? WHERE Seq = ".$self->seq(),
+				 $errname);
+	}
     } elsif(not $opt::ungroup) {
 	# To group we create temporary files for STDOUT and STDERR
 	# To avoid the cleanup unlink the files immediately (but keep them open)
@@ -6404,6 +6480,9 @@ sub set_starttime {
     my $self = shift;
     my $starttime = shift || ::now();
     $self->{'starttime'} = $starttime;
+    $opt::sqlworker and
+	$Global::sql->update("SET Starttime = ? WHERE Seq = ".$self->seq(),
+			     $starttime);
 }
 
 sub runtime {
@@ -6425,6 +6504,9 @@ sub set_endtime {
     my $self = shift;
     my $endtime = shift;
     $self->{'endtime'} = $endtime;
+    $opt::sqlworker and
+	$Global::sql->update("SET JobRuntime = ? WHERE Seq = ".$self->seq(),
+			     $self->runtime());
 }
 
 sub is_timedout {
@@ -6635,6 +6717,14 @@ sub wrapped {
 		';';
 	}
 	if($ENV{'PARALLEL_ENV'}) {
+	    if(-e $ENV{'PARALLEL_ENV'}) {
+		# This is a file/fifo: Replace envvar with content of file
+		open(my $parallel_env, "<", $ENV{'PARALLEL_ENV'}) ||
+		    ::die_bug("Cannot read parallel_env from $ENV{'PARALLEL_ENV'}");
+		local $/;
+		$ENV{'PARALLEL_ENV'} = <$parallel_env>;
+		close $parallel_env;
+	    }
 	    # If $PARALLEL_ENV set, put that in front of the command
 	    # Used for importing functions for fish
 	    # Map \001 to \n to make it easer to quote \n in $PARALLEL_ENV
@@ -6664,8 +6754,11 @@ sub wrapped {
 	   and
 	   length $command > 499) {
 	    # csh does not like words longer than 1000 (499 quoted)
-	    $command = "perl -e '".base64_zip_eval()."' ".
+	    # bzip2 breaks --sql mysql://...
-		join" ",string_zip_base64('exec "'.::perl_quote_scalar($command).'"');
+	    # $command = "perl -e '".base64_zip_eval()."' ".
+	    # join" ",string_zip_base64('exec "'.::perl_quote_scalar($command).'"');
+	    $command = "perl -e '".base64_eval()."' ".
+		join" ",string_base64('exec "'.::perl_quote_scalar($command).'"');
 	}
 	$self->{'wrapped'} = $command;
     }
@@ -6678,6 +6771,9 @@ sub set_sshlogin {
     $self->{'sshlogin'} = $sshlogin;
     delete $self->{'sshlogin_wrap'}; # If sshlogin is changed the wrap is wrong
     delete $self->{'wrapped'};
+    $opt::sqlworker and
+	$Global::sql->update("SET Host = ? WHERE Seq = ".$self->seq(),
+			     $sshlogin->string());
 }
 
 sub sshlogin {
@@ -6685,6 +6781,18 @@ sub sshlogin {
     return $self->{'sshlogin'};
 }
 
+sub string_base64 {
+    # Base64 encode it into 1000 byte blocks.
+    # 1000 bytes is the largest word size csh supports
+    # Input:
+    #   @strings = to be encoded
+    # Returns:
+    #   @base64 = 1000 byte block
+    $Global::use{"MIME::Base64"} ||= eval "use MIME::Base64; 1;";
+    my @base64 = unpack("(A1000)*",encode_base64((join"",@_),""));
+    return @base64;
+}
+
 sub string_zip_base64 {
     # Pipe string through 'bzip2 -9' and base64 encode it into 1000
     # byte blocks.
@@ -6707,7 +6815,7 @@ sub string_zip_base64 {
 	close $zipin_fh;
 	exit;
     }
-    ::debug("base64","Orig:@_\nAs base64:@base64\n");
+    ::debug("base64","Orig:@_\nAs bzip2 base64:@base64\n");
     return @base64;
 }
 
@@ -6749,6 +6857,26 @@ sub base64_zip_eval {
     return $script;
 }
 
+sub base64_eval {
+    # Script that:
+    #   * reads base64 strings from @ARGV
+    #   * decodes them
+    #   * evals the result
+    # Reverse of string_base64 + eval
+    # Will be wrapped in ' so single quote is forbidden
+    # Returns:
+    #   $script = 1-liner for perl -e
+    my $script = ::spacefree(0,q{
+        @GNU_Parallel=("use","IPC::Open3;","use","MIME::Base64");
+        eval "@GNU_Parallel";
+        my $eval;
+	$eval = decode_base64(join"",@ARGV);
+	eval $eval;
+			     });
+    ::debug("base64",$script,"\n");
+    return $script;
+}
+
 sub sshlogin_wrap {
     # Wrap the command with the commands needed to run remotely
     # Input:
@@ -6913,8 +7041,11 @@ sub sshlogin_wrap {
 		   $command =~ /\n/) {
 		    # csh does not deal well with > 1000 chars in one word
 		    # csh does not deal well with $ENV with \n
-		    $env_command = "perl -e '".base64_zip_eval()."' ".
+		    # bzip2 breaks --sql mysql://...
-			join" ",string_zip_base64($env_command);
+		    # $env_command = "perl -e '".base64_zip_eval()."' ".
+		    # join" ",string_zip_base64($env_command);
+		    $env_command = "perl -e '".base64_eval()."' ".
+			join" ",string_base64($env_command);
 		    $self->{'sshlogin_wrap'} = $env_command;
 		} else {
 		    $self->{'sshlogin_wrap'} = "perl -e ".::shell_quote_scalar($env_command);
@@ -6942,8 +7073,11 @@ sub sshlogin_wrap {
 	       $command =~ /\n/) {
 		# csh does not deal well with > 1000 chars in one word
 		# csh does not deal well with $ENV with \n
-		$quoted_remote_command = "perl -e \\''".base64_zip_eval()."'\\' ".
+		# bzip2 breaks --sql mysql://...
-		    join" ",string_zip_base64($remote_command);
+		# $quoted_remote_command = "perl -e \\''".base64_zip_eval()."'\\' "."".
+		# join" ",string_zip_base64($remote_command);
+		$quoted_remote_command = "perl -e \\''".base64_eval()."'\\' ".
+		    join" ",string_base64($remote_command);
 	    } else {
 		$quoted_remote_command = $dq_remote_command;
 	    }
@@ -6999,6 +7133,9 @@ sub add_transfersize {
     my $self = shift;
     my $transfersize = shift;
     $self->{'transfersize'} += $transfersize;
+    $opt::sqlworker and
+	$Global::sql->update("SET Send = ? WHERE Seq = ".$self->seq(),
+			     $self->{'transfersize'});
 }
 
 sub sshtransfer {
@@ -7041,6 +7178,9 @@ sub add_returnsize {
     my $self = shift;
     my $returnsize = shift;
     $self->{'returnsize'} += $returnsize;
+    $opt::sqlworker and
+	$Global::sql->update("SET Receive = ? WHERE Seq = ".$self->seq(),
+			     $self->{'returnsize'});
 }
 
 sub sshreturn {
@@ -7275,10 +7415,10 @@ sub start {
     }
     $job->openoutputfiles();
     my($stdout_fh,$stderr_fh) = ($job->fh(1,"w"),$job->fh(2,"w"));
-    if($opt::ungroup) {
+    if($opt::ungroup or $opt::sqlworker) {
 	print_dryrun_and_verbose($stdout_fh,$job,$command);
     }
-    if($opt::dryrun) { $command = "true"; }
+    if($opt::dryrun or $opt::sql) { $command = "true"; }
     $ENV{'PARALLEL_SEQ'} = $job->seq();
     $ENV{'PARALLEL_PID'} = $$;
     $ENV{'PARALLEL_TMP'} = ::tmpname("par");
@@ -7381,6 +7521,10 @@ sub print_dryrun_and_verbose {
 	    print $stdout_fh $command,"\n";
 	}
     }
+    if($opt::sqlworker) {
+	$Global::sql->update("SET Command = ? WHERE Seq = ".$job->seq(),
+			     $job->replaced());
+    }
 }
 
 {
@@ -7567,7 +7711,11 @@ sub print {
 
 	if(($opt::dryrun or $Global::verbose)
 	   and
-	   not $self->{'verbose_printed'}) {
+	   not $self->{'verbose_printed'}
+	   and
+	   not $opt::sql
+	   and
+	   not $opt::sqlworker) {
 	    $self->{'verbose_printed'}++;
 	    if($Global::verbose <= 1) {
 		print STDOUT $self->replaced(),"\n";
@@ -7638,6 +7786,10 @@ sub files_print {
 	}
     } elsif($fdno == 1 and $self->fh($fdno,"name")) {
 	print $out_fd $self->tag(),$self->fh($fdno,"name"),"\n";
+	if($opt::sqlworker) {
+	    $Global::sql->update("SET Stdout = ? WHERE Seq = ".$self->seq(),
+				 $self->tag().$self->fh($fdno,"name"));
+	}
 	$self->add_returnsize(-s $self->fh($fdno,"name"));
     }
 }
@@ -7781,12 +7933,25 @@ sub normal_print {
     seek $in_fh, 0, 0;
     # $in_fh is now ready for reading at position 0
     my $outputlength = 0;
+    my @output;
     while(sysread($in_fh,$buf,131072)) {
 	print $out_fd $buf;
 	$outputlength += length $buf;
+	if($opt::sqlworker) {
+	    push @output, $buf;
+	}
     }
     if($fdno == 1) {
 	$self->add_returnsize($outputlength);
+	if($opt::sqlworker and not $opt::results) {
+	    $Global::sql->update("SET Stdout = ? WHERE Seq = ".$self->seq(),
+				 join("",@output));
+	}
+    } else {
+	if($opt::sqlworker and not $opt::results) {
+	    $Global::sql->update("SET Stderr = ? WHERE Seq = ".$self->seq(),
+				 join("",@output));
+	}
     }
     close $in_fh;
     if($? and $opt::compress) {
@@ -7851,6 +8016,9 @@ sub set_exitstatus {
 	# Status may have been set by --timeout
 	$self->{'exitstatus'} ||= $exitstatus;
     }
+    $opt::sqlworker and
+	$Global::sql->update("SET Exitval = ? WHERE Seq = ".$self->seq(),
+			     $exitstatus);
 }
 
 sub reset_exitstatus {
@@ -7867,9 +8035,11 @@ sub set_exitsignal {
     my $self = shift;
     my $exitsignal = shift;
     $self->{'exitsignal'} = $exitsignal;
+    $opt::sqlworker and
+	$Global::sql->update("SET _Signal = ? WHERE Seq = ".$self->seq(),
+			     $exitsignal);
 }
 
-
 {
     my $status_printed;
     my $total_jobs;
@@ -8092,6 +8262,10 @@ sub populate {
 	    }
 	}
     }
+    if($opt::sql) {
+	# Insert the V1..Vn for this $seq in SQL table instead of generating one
+	$Global::sql->insert_records($self->seq(),$self->{'arg_list_flat_orig'});
+    }
 }
 
 sub push {
@@ -8715,6 +8889,10 @@ sub get {
 					$self->{'len'},
 	    );
 	$cmd_line->populate();
+	if($opt::sqlworker) {
+	    # Get the sequence number from the SQL table
+	    $cmd_line->set_seq($SQL::next_seq);
+	}
 	::debug("init","cmd_line->number_of_args ",
 		$cmd_line->number_of_args(), "\n");
 	if(not $Global::no_more_input and ($opt::pipe or $opt::pipepart)) {
@@ -8893,7 +9071,10 @@ sub new {
     my $colsep = shift;
     my @unget = ();
     my $arg_sub_queue;
-    if($colsep) {
+    if($opt::sqlworker) {
+	# Open SQL table
+	$arg_sub_queue = SQLRecordQueue->new();
+    } elsif($colsep) {
 	# Open one file with colsep
 	$arg_sub_queue = RecordColQueue->new($fhs);
     } else {
@@ -9017,6 +9198,45 @@ sub empty {
 }
 
 
+package SQLRecordQueue;
+
+sub new {
+    my $class = shift;
+    my @unget = ();
+    return bless {
+	'unget' => \@unget,
+    }, ref($class) || $class;
+}
+
+sub get {
+    # Returns:
+    #   reference to array of Arg-objects
+    my $self = shift;
+    if(@{$self->{'unget'}}) {
+	return shift @{$self->{'unget'}};
+    }
+    return $Global::sql->get_record();
+}
+
+sub unget {
+    my $self = shift;
+    ::debug("run", "SQLRecordQueue-unget '@_'\n");
+    unshift @{$self->{'unget'}}, @_;
+}
+
+sub empty {
+    my $self = shift;
+    if(@{$self->{'unget'}}) { return 0; }
+    my $get = $self->get();
+    if(defined $get) {
+	$self->unget($get);
+    }
+    my $empty = not $get;
+    ::debug("run", "SQLRecordQueue->empty $empty");
+    return $empty;
+}
+
+
 package MultifileQueue;
 
 @Global::unget_argv=();
@@ -9463,6 +9683,323 @@ sub insert {
 }
 
 
+package SQL;
+
+sub new {
+    my $class = shift;
+    my $dburl = shift;
+    $Global::use{"DBI"} ||= eval "use DBI; 1;";
+    my %options = parse_dburl(get_alias($dburl));
+    my %driveralias = ("sqlite" => "SQLite",
+		       "sqlite3" => "SQLite",
+		       "pg" => "Pg",
+		       "postgres" => "Pg",
+		       "postgresql" => "Pg");
+    my $driver = $driveralias{$options{'databasedriver'}} || $options{'databasedriver'};
+    my $database = $options{'database'};
+    my $host = $options{'host'} ? ";host=".$options{'host'} : "";
+    my $port = $options{'port'} ? ";port=".$options{'port'} : "";
+    my $dsn = "DBI:$driver:dbname=$database$host$port";
+    my $userid = $options{'user'};
+    my $password = $options{'password'};;
+    my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
+	or die $DBI::errstr;
+    return bless {
+	'dbh' => $dbh,
+	'max_number_of_args' => undef,
+	'table' => $options{'table'},
+    }, ref($class) || $class;
+}
+
+sub get_alias {
+    my $alias = shift;
+    $alias =~ s/^(sql:)*//; # Accept aliases prepended with sql:
+    if ($alias !~ /^:/) {
+	return $alias;
+    }
+
+    # Find the alias
+    my $path;
+    if (-l $0) {
+	($path) = readlink($0) =~ m|^(.*)/|;
+    } else {
+	($path) = $0 =~ m|^(.*)/|;
+    }
+
+    my @deprecated = ("$ENV{HOME}/.dburl.aliases",
+		      "$path/dburl.aliases", "$path/dburl.aliases.dist");
+    for (@deprecated) {
+	if(-r $_) {
+	    print STDERR "$_ is deprecated. Use .sql/aliases instead (read man sql)\n";
+	}
+    }
+    my @urlalias=();
+    check_permissions("$ENV{HOME}/.sql/aliases");
+    check_permissions("$ENV{HOME}/.dburl.aliases");
+    my @search = ("$ENV{HOME}/.sql/aliases",
+		  "$ENV{HOME}/.dburl.aliases", "/etc/sql/aliases",
+		  "$path/dburl.aliases", "$path/dburl.aliases.dist");
+    for my $alias_file (@search) {
+	if(-r $alias_file) {
+	    push @urlalias, `cat "$alias_file"`;
+	}
+    }
+    my ($alias_part,$rest) = $alias=~/(:\w*)(.*)/;
+    # If we saw this before: we have an alias loop
+    if(grep {$_ eq $alias_part } @Private::seen_aliases) {
+	print STDERR "$alias_part is a cyclic alias\n";
+	exit -1;
+    } else {
+	push @Private::seen_aliases, $alias_part;
+    }
+
+    my $dburl;
+    for (@urlalias) {
+	/^$alias_part\s+(\S+.*)/ and do { $dburl = $1; last; }
+    }
+
+    if($dburl) {
+	return get_alias($dburl.$rest);
+    } else {
+	Usage("$alias is not defined in @search");
+	exit(-1);
+    }
+}
+
+sub check_permissions {
+    my $file = shift;
+
+    if(-e $file) {
+	if(not -o $file) {
+	    my $username = (getpwuid($<))[0];
+	    print STDERR "$file should be owned by $username: chown $username $file\n";
+	}
+	my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
+	    $atime,$mtime,$ctime,$blksize,$blocks) = stat($file);
+	if($mode & 077) {
+	    my $username = (getpwuid($<))[0];
+	    print STDERR "$file should be only be readable by $username: chmod 600 $file\n";
+	}
+    }
+}
+
+sub parse_dburl {
+    my $url = shift;
+    my %options = ();
+    # sql:mysql://[[user][:password]@][host][:port]/[database[/table][?sql query]]
+
+    if($url=~m!(?:sql:)? # You can prefix with 'sql:'
+               ((?:oracle|ora|mysql|pg|postgres|postgresql)(?:s|ssl|)|
+                 (?:sqlite|sqlite2|sqlite3)):// # Databasedriver ($1)
+               (?:
+                ([^:@/][^:@]*|) # Username ($2)
+                (?:
+                 :([^@]*) # Password ($3)
+                )?
+               @)?
+               ([^:/]*)? # Hostname ($4)
+               (?:
+                :
+                ([^/]*)? # Port ($5)
+               )?
+               (?:
+                /
+                ([^/?]*)? # Database ($6)
+               )?
+               (?:
+                /
+                ([^?]*)? # Table ($7)
+               )?
+               (?:
+                \?
+                (.*)? # Query ($8)
+               )?
+              !ix) {
+	$options{databasedriver} = ::undef_if_empty(lc(uri_unescape($1)));
+	$options{user} = ::undef_if_empty(uri_unescape($2));
+	$options{password} = ::undef_if_empty(uri_unescape($3));
+	$options{host} = ::undef_if_empty(uri_unescape($4));
+	$options{port} = ::undef_if_empty(uri_unescape($5));
+	$options{database} = ::undef_if_empty(uri_unescape($6));
+	$options{table} = ::undef_if_empty(uri_unescape($7));
+	$options{query} = ::undef_if_empty(uri_unescape($8));
+	::debug("sql","dburl $url\n");
+	::debug("sql","databasedriver ",$options{databasedriver}, " user ", $options{user},
+	      " password ", $options{password}, " host ", $options{host},
+	      " port ", $options{port}, " database ", $options{database},
+	      " table ",$options{table}," query ",$options{query}, "\n");
+
+    } else {
+	::error("$url is not a valid DBURL");
+	exit 255;
+    }
+    return %options;
+}
+
+sub uri_unescape {
+    # Copied from http://cpansearch.perl.org/src/GAAS/URI-1.55/URI/Escape.pm
+    # to avoid depending on URI::Escape
+    # This section is (C) Gisle Aas.
+    # Note from RFC1630:  "Sequences which start with a percent sign
+    # but are not followed by two hexadecimal characters are reserved
+    # for future extension"
+    my $str = shift;
+    if (@_ && wantarray) {
+	# not executed for the common case of a single argument
+	my @str = ($str, @_);  # need to copy
+	foreach (@str) {
+	    s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
+	}
+	return @str;
+    }
+    $str =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg if defined $str;
+    $str;
+}
+
+sub run {
+    my $self = shift;
+    my $stmt = shift;
+    my @retval;
+    my $dbh = $self->{'dbh'};
+    ::debug("sql","$opt::sql$opt::sqlworker run $stmt\n");
+    # Execute with the rest of the args - if any
+    my $rv;
+    my $sth;
+    my $lockretry = 0;
+    while($lockretry < 10) {
+	$sth = $dbh->prepare($stmt);
+	if($rv = $sth->execute(@_)) {
+	    last;
+	} else {
+	    if($DBI::errstr =~ /locked/) {
+		::debug("sql","Lock retry: $lockretry");
+		$lockretry++;
+	    } else {
+		::error($DBI::errstr);
+	    }
+	}
+    }
+    if($rv < 0){
+	print $DBI::errstr;
+    }
+    return $sth;
+}
+
+sub get {
+    my $self = shift;
+    my $sth = $self->run(@_);
+    my @retval;
+    while(1) {
+	my @row = $sth->fetchrow_array();
+	@row or last;
+	push @retval, \@row;
+    }
+    return \@retval;
+}
+
+sub table {
+    my $self = shift;
+    return $self->{'table'};
+}
+
+sub update {
+    my $self = shift;
+    my $stmt = shift;
+    my $table = $self->table();
+    $self->run("UPDATE $table $stmt",@_);
+}
+
+sub max_number_of_args {
+    # Maximal number of args for this table
+    my $self = shift;
+    if(not $self->{'max_number_of_args'}) {
+	# Read the number of args from the SQL table
+	my $table = $self->table();
+	my $v = $self->get("SELECT * FROM $table LIMIT 1;");
+	my @reserved_columns = qw(Seq Host Starttime JobRuntime Send
+	    Receive Exitval _Signal Command Stdout Stderr);
+	if(not $v) {
+	    ::error("$table contains no records");
+	}
+	# Count the number of Vx columns
+	$self->{'max_number_of_args'} = $#{$v->[0]} - $#reserved_columns;
+    }
+    return $self->{'max_number_of_args'};
+}
+
+sub set_max_number_of_args {
+    my $self = shift;
+    $self->{'max_number_of_args'} = shift;
+}
+
+sub create_table {
+    my $self = shift;
+    my $max_number_of_args = shift;
+    $self->set_max_number_of_args($max_number_of_args);
+    my $table = $self->table();
+    $self->run(qq(DROP TABLE IF EXISTS $table;));
+    my $v_def = join "", map { "V$_ TEXT," } (1..$self->max_number_of_args());
+    $self->run(qq{CREATE TABLE $table
+		(Seq INT,
+		 Host TEXT,
+		 Starttime REAL,
+		 JobRuntime REAL,
+		 Send INT,
+		 Receive INT,
+		 Exitval INT,
+		 _Signal INT,
+		 Command TEXT,}.
+	       $v_def.
+	       qq{Stdout TEXT,
+		 Stderr TEXT);});
+}
+
+sub insert_records {
+    my $self = shift;
+    my $seq = shift;
+    my $record_ref = shift;
+    my $table = $self->table();
+    my $v_cols = join ",", map { "V$_" } (1..$self->max_number_of_args());
+    # Two extra value due to $seq, Exitval
+    my $v_vals = join ",", map { "?" } (1..$self->max_number_of_args()+2);
+    $self->run("INSERT INTO $table (Seq,Exitval,$v_cols) ".
+	       "VALUES ($v_vals);", $seq, -1000, @$record_ref[1..$#$record_ref]);
+}
+
+sub get_record {
+    my $self = shift;
+    my @retval;
+    my $table = $self->table();
+    my $v_cols = join ",", map { "V$_" } (1..$self->max_number_of_args());
+    my $v = $self->get("SELECT Seq, $v_cols FROM $table ".
+		       "WHERE Exitval = -1000 ORDER BY Seq LIMIT 1;");
+    if($v->[0]) {
+	my $val_ref = $v->[0];
+	# Mark record as taken
+	my $seq = shift @$val_ref;
+	# Save the sequence number to use when running the job
+	$SQL::next_seq = $seq;
+	$self->update("SET Exitval = ? WHERE Seq = ".$seq, -1220);
+	for (@$val_ref) {
+	    push @retval, Arg->new($_);
+	}
+    }
+    if(@retval) {
+	return \@retval;
+    } else {
+	return undef;
+    }
+}
+
+sub finished {
+    # Check if there are any jobs left in the SQL table that do not
+    # have a "real" exitval
+    my $self = shift;
+    my $table = $self->table();
+    my $rv = $self->get("select Seq,Exitval from $table where Exitval <= -1000 limit 1");
+    return not $rv->[0];
+}
+
 package Semaphore;
 
 # This package provides a counting semaphore

src/parallel.pod

@@ -514,7 +514,7 @@ should feel free to use B<--will-cite>.
 Size of block in bytes to read at a time. The I<size> can be postfixed
 with K, M, G, T, P, k, m, g, t, or p which would multiply the size
 with 1024, 1048576, 1073741824, 1099511627776, 1125899906842624, 1000,
-1000000, 1000000000, 1000000000000, or 1000000000000000 respectively.
+1000000, 1000000000, 1000000000000, or 1000000000000000, respectively.
 
 GNU B<parallel> tries to meet the block size but can be off by the
 length of one record. For performance reasons I<size> should be bigger
@@ -1088,7 +1088,7 @@ most likely do what is needed.
 
 Multiple arguments. Insert as many arguments as the command line
 length permits. If multiple jobs are being run in parallel: distribute
-the arguments evenly among the jobs. Use B<-j1> to avoid this.
+the arguments evenly among the jobs. Use B<-j1> or B<--xargs> to avoid this.
 
 If B<{}> is not used the arguments will be appended to the
 line.  If B<{}> is used multiple times each B<{}> will be replaced
@@ -1106,7 +1106,7 @@ Minimum memory free when starting another job. The I<size> can be
 postfixed with K, M, G, T, P, k, m, g, t, or p which would multiply
 the size with 1024, 1048576, 1073741824, 1099511627776,
 1125899906842624, 1000, 1000000, 1000000000, 1000000000000, or
-1000000000000000 respectively.
+1000000000000000, respectively.
 
 If the jobs take up very different amount of RAM, GNU B<parallel> will
 only start as many as there is memory for. If less than I<size> bytes
@@ -1791,6 +1791,50 @@ Do not use the first line of input (used by GNU B<parallel> itself
 when called with B<--shebang>).
 
 
+=item B<--sql> I<DBURL> (alpha testing)
+
+Submit jobs via SQL server. I<DBURL> must point to a table, which will
+contain the same information as B<--joblog>, the values from the input
+sources (stored in columns V1 .. Vn), and the output (stored in
+columns Stdout and Stderr).
+
+The table will be dropped and created with the correct amount of
+V-columns.
+
+B<--sql> does not run any jobs, but it creates the values for the jobs
+to be run and wait for them to complete. One or more B<--sqlworker>
+must be run to actually execute the jobs.
+
+The format of a DBURL is:
+
+  [sql:]vendor://[[user][:password]@][host][:port]/[database]/table
+
+E.g.
+
+  sql:mysql://hr:hr@localhost:3306/hrdb/jobs
+  mysql://scott:tiger@my.example.com/pardb/paralleljobs
+  sql:oracle://scott:tiger@ora.example.com/xe/parjob
+  postgresql://scott:tiger@pg.example.com/pgdb/parjob
+  pg:///parjob
+  sqlite3:///pardb/parjob
+
+It can also be an alias from ~/.sql/aliases:
+
+  :myalias mysql:///mydb/paralleljobs
+
+
+=item B<--sqlandworker> I<DBURL> (alpha testing)
+
+Shorthand for: B<--sql> I<DBURL> B<--sqlworker> I<DBURL>.
+
+
+=item B<--sqlworker> I<DBURL> (alpha testing)
+
+Execute jobs via SQL server. Read the input sources variables from the
+table pointed to by I<DBURL>. The I<command> on the command line
+should be the same as given by B<--sql>.
+
+
 =item B<--ssh> I<sshcommand>
 
 GNU B<parallel> defaults to using B<ssh> for remote access. This can
@@ -2579,7 +2623,8 @@ files.
   tar xvf foo.tgz | perl -ne 'print $l;$l=$_;END{print $l}' | \
     parallel echo
 
-The Perl one-liner is needed to avoid race condition.
+The Perl one-liner is needed to make sure the file is complete before
+handing it to GNU B<parallel>.
 
 
 =head1 EXAMPLE: Rewriting a for-loop and a while-read-loop
@@ -3410,6 +3455,35 @@ computers:
 
   true >jobqueue; tail -n+0 -f jobqueue | parallel -S ..
 
+If you keep this running for a long time, jobqueue will grow. A way of
+removing the jobs already run is by making GNU B<parallel> stop when
+it hits a special value and then restart. To use B<--eof> to make GNU
+B<parallel> exit, B<tail> also needs to be forced to exit:
+
+  true >jobqueue;
+  while true; do
+    tail -n+0 -f jobqueue |
+      (parallel -E StOpHeRe -S ..; echo GNU Parallel is now done;
+       perl -e 'while(<>){/StOpHeRe/ and last};print <>' jobqueue > j2;
+       (seq 1000 >> jobqueue &);
+       echo Done appending dummy data forcing tail to exit)
+    echo tail exited;
+    mv j2 jobqueue
+  done
+
+In some cases you can run on more CPUs and computers during the night:
+
+  # Day time
+  echo 50% > jobfile
+  cp day_server_list ~/.parallel/sshloginfile
+  # Night time
+  echo 100% > jobfile
+  cp night_server_list ~/.parallel/sshloginfile
+  tail -n+0 -f jobqueue | parallel --jobs jobfile -S ..
+
+GNU Parallel discovers if B<jobfile> or B<~/.parallel/sshloginfile>
+changes.
+
 There is a a small issue when using GNU B<parallel> as queue
 system/batch manager: You have to submit JobSlot number of jobs before
 they will start, and after that you can submit one at a time, and job
@@ -3421,14 +3495,6 @@ E.g. if you have 10 jobslots then the output from the first completed
 job will only be printed when job 11 has started, and the output of
 second completed job will only be printed when job 12 has started.
 
-To use B<--eof> to make GNU B<parallel> exit, B<tail> also needs to be
-forced to exit:
-
-  tail -n+0 -f command-list.txt |
-    (parallel --eof=EXIT {}; echo Parallel is now done;
-     (seq 1000 >> command-list.txt &);
-    echo Done appending dummy data forcing tail to exit)
-
 
 =head1 EXAMPLE: GNU Parallel as dir processor
 
@@ -3773,6 +3839,26 @@ More than 100 jobs failed.
 
 Other error.
 
+=item Z<>-1 (In joblog and SQL table)
+
+Killed by Ctrl-C, timeout, not enough memory or similar.
+
+=item Z<>-2 (In joblog and SQL table)
+
+$job->skip() was called in {= =}.
+
+=item Z<>-1200 (In SQL table)
+
+Job is ready to run (used with --sql).
+
+=item Z<>-1220 (In SQL table)
+
+Job is taken by worker to be started (used with --sql).
+
+=item Z<>-1250 (In SQL table)
+
+Job is running (used with --sql).
+
 =back
 
 If fail=1 is used, the exit status will be the exit status of the

src/parallel_design.pod

@@ -32,7 +32,7 @@ is CentOS 3.9 and Perl 5.8.0.
 GNU B<parallel> busy waits. This is because the reason why a job is
 not started may be due to load average, and thus it will not make
 sense to wait for a job to finish. Instead the load average must be
-checked again. Load average is not the only reason: --timeout has a
+checked again. Load average is not the only reason: B<--timeout> has a
 similar problem.
 
 To not burn up too much CPU GNU B<parallel> sleeps exponentially
@@ -56,14 +56,13 @@ The easiest way to explain what GNU B<parallel> does is to assume that
 there are a number of job slots, and when a slot becomes available a
 job from the queue will be run in that slot. But originally GNU
 B<parallel> did not model job slots in the code. Job slots have been
-added to make it possible to use {%} as a replacement string.
+added to make it possible to use B<{%}> as a replacement string.
 
-While the job
+While the job sequence number can be computed in advance, the job slot
-sequence number can be computed in advance, the job slot can only be
+can only be computed the moment a slot becomes available. So it has
-computed the moment a slot becomes available. So it has been
+been implemented as a stack with lazy evaluation: Draw one from an
-implemented as a stack with lazy evaluation: Draw one from an empty
+empty stack and the stack is extended by one. When a job is done, push
-stack and the stack is extended by one. When a job is done, push the
+the available job slot back on the stack.
-available job slot back on the stack.
 
 This implementation also means that if you use remote executions, you
 cannot assume that a given job slot will remain on the same remote
@@ -89,7 +88,7 @@ B<--compress> compresses the data in the temporary files. This is a
 bit tricky because there should be no files to clean up if GNU
 B<parallel> is killed by a power outage.
 
-GNU B<parallel> first selects a compress program. If the user has not
+GNU B<parallel> first selects a compression program. If the user has not
 selected one, the first of these that are in $PATH is used: B<lz4 pigz
 lzop plzip pbzip2 pxz gzip lzma xz bzip2 lzip>. They are sorted by
 speed on a 16 core machine.
@@ -102,16 +101,16 @@ Schematically the setup is as follows:
 The setup is duplicated for both standard output (stdout) and standard
 error (stderr).
 
-GNU B<parallel> pipes output from the command run into the compress
+GNU B<parallel> pipes output from the command run into the compression
 program which saves to a tmpfile. GNU B<parallel> records the pid of
 the compress program.  At the same time a small perl script (called
 B<cattail> above) is started: It basically does B<cat> followed by
 B<tail -f>, but it also removes the tmpfile as soon as the first byte
-is read, and it continously checks if the pid of the compress program
+is read, and it continously checks if the pid of the compression
-is dead. If the compress program is dead, B<cattail> reads the rest of
+program is dead. If the compress program is dead, B<cattail> reads the
-tmpfile and exits.
+rest of tmpfile and exits.
 
-As most compress programs write out a header when they start, the
+As most compression programs write out a header when they start, the
 tmpfile in practice is unlinked after around 40 ms.
 
 
@@ -137,12 +136,8 @@ Local: B<setpriority(0,0,$nice)>
   cat > {}; I<input> {};
   perl -e '$bash = shift;
     $csh = shift;
-         for(@ARGV) {
+    for(@ARGV) { unlink;rmdir; }
-           unlink;rmdir;
+    if($bash =~ s/h//) { exit $bash;  }
-         }
-         if($bash =~ s/h//) {
-           exit $bash;
-         }
     exit $csh;' "$?h" "$status" {};
 
 {} is set to $PARALLEL_TMP which is a tmpfile. The Perl script saves
@@ -261,8 +256,6 @@ the FIFO, and this value is used as exit value.
 To make it compatible with B<csh> and B<bash> the exit value is
 printed as: $?h/$status and this is parsed by B<perl>.
 
-Works in B<csh>.
-
 There is a bug that makes it necessary to print the exit value 3
 times.
 
@@ -306,23 +299,6 @@ B<--pipepart>/B<--pipe> should be done on the local machine inside B<--tmux>
 =back
 
 
-=head2 --block-size adjustment
-
-Every time GNU B<parallel> detects a record bigger than
-B<--block-size> it increases the block size by 30%. A small
-B<--block-size> gives very poor performance; by exponentially
-increasing the block size performance will not suffer.
-
-GNU B<parallel> will waste CPU power if B<--block-size> does not
-contain a full record, because it tries to find a full record and will
-fail to do so. The recommendation is therefore to use a
-B<--block-size> > 2 records, so you always get at least one full
-record when you read one block.
-
-If you use B<-N> then B<--block-size> should be big enough to contain
-N+1 records.
-
-
 =head2 Convenience options --nice --basefile --transfer --return
 --cleanup --tmux --group --compress --cat --fifo --workdir
 
@@ -360,6 +336,23 @@ that correctly for all corner cases is next to impossible to do by
 hand.
 
 
+=head2 --block-size adjustment
+
+Every time GNU B<parallel> detects a record bigger than
+B<--block-size> it increases the block size by 30%. A small
+B<--block-size> gives very poor performance; by exponentially
+increasing the block size performance will not suffer.
+
+GNU B<parallel> will waste CPU power if B<--block-size> does not
+contain a full record, because it tries to find a full record and will
+fail to do so. The recommendation is therefore to use a
+B<--block-size> > 2 records, so you always get at least one full
+record when you read one block.
+
+If you use B<-N> then B<--block-size> should be big enough to contain
+N+1 records.
+
+
 =head2 Shell shock
 
 The shell shock bug in B<bash> did not affect GNU B<parallel>, but the
@@ -402,10 +395,14 @@ exec'ing a Perl wrapper to monitor the parent pid and kill the child
 if the parent pid becomes 1, then Ctrl-C works and stderr is kept on
 stderr.
 
+To be able to kill all (grand)*children a new process group is
+started.
+
 =head3 --nice
 
 B<nice>ing the remote process is done by B<setpriority(0,0,$nice)>. A
-few old systems do not implement this and is thus unsupported.
+few old systems do not implement this and B<--nice> is unsupported on
+those.
 
 =head3 Setting $PARALLEL_TMP
 
@@ -449,7 +446,7 @@ The wrapper looks like this:
 
 Transferring of variables and functions given by B<--env> is done by
 running a Perl script remotely that calls the actual command. The Perl
-script sets $ENV{variable} to the correct value before exec'ing the a
+script sets B<$ENV{>I<variable>B<}> to the correct value before exec'ing the a
 shell that runs the function definition followed by the actual
 command.
 
@@ -512,9 +509,9 @@ shell is used when GNU B<parallel> executes commands.
 GNU B<parallel> tries hard to use the right shell. If GNU B<parallel>
 is called from B<tcsh> it will use B<tcsh>.  If it is called from
 B<bash> it will use B<bash>. It does this by looking at the
-(grand*)parent process: If the (grand*)parent process is a shell, use
+(grand)*parent process: If the (grand)*parent process is a shell, use
-this shell; otherwise look at the parent of this (grand*)parent. If
+this shell; otherwise look at the parent of this (grand)*parent. If
-none of the (grand*)parents are shells, then $SHELL is used.
+none of the (grand)*parents are shells, then $SHELL is used.
 
 This will do the right thing if called from:
 
@@ -570,7 +567,7 @@ not known to B<bash>.
 =back
 
 If GNU B<parallel> guesses wrong in these situation, set the shell using
-$PARALLEL_SHELL.
+B<$PARALLEL_SHELL>.
 
 =head2 Quoting
 
@@ -596,7 +593,7 @@ implemented very differently.
 With B<--pipe> GNU B<parallel> reads the blocks from standard input
 (stdin), which is then given to the command on standard input (stdin);
 so every block is being processed by GNU B<parallel> itself. This is
-the reason why B<--pipe> maxes out at around 100 MB/sec.
+the reason why B<--pipe> maxes out at around 500 MB/sec.
 
 B<--pipepart>, on the other hand, first identifies at which byte
 positions blocks start and how long they are. It does that by seeking
@@ -766,42 +763,32 @@ B<ps> and put the result in a file, which is then used next time.
 
 =head2 Killing jobs
 
-B<--memfree>, B<--halt> and when GNU B<parallel> meets a condition
+GNU B<parallel> kills jobs. It can be due to B<--memfree>, B<--halt>,
-from which it cannot recover, jobs are killed. This is done by finding
+or when GNU B<parallel> meets a condition from which it cannot
-the (grand)*children of the jobs and killing those processes.
+recover. Every job is started as its own process group. This way any
+(grand)*children will get killed, too. The process group is killed with
+the specification mentioned in B<--termseq>.
 
-More specifically GNU B<parallel> maintains a list of processes to be
-killed, sends a signal to all processes (first round this is a TERM).
-It weeds out the processes that exited from the list then waits a
-while and weeds out again. It does that until all processes are dead
-or 200 ms passed. Then it does another round with TERM, and finally a
-round with KILL.
 
-  pids = family_pids(jobs)
+=head2 SQL interface
-  for signal in TERM, TERM, KILL:
-    for pid in pids:
-      kill signal, pid
-    while kill 0, pids and slept < 200 ms:
-      sleep sleeptime
-      pids = kill 0, pids
-      slept += sleeptime
-      sleeptime = sleeptime * 1.1
 
-By doing so there is a tiny risk, that GNU B<parallel> will kill
+GNU B<parallel> uses the DBURL from GNU B<sql> to give database
-processes that are not started from GNU B<parallel>. It, however,
+software, username, password, host, port, database, and table in a
-requires all of these to be true:
+single string.
 
-* Process A is sent a signal
+The DBURL must point to a table name. The table will be dropped and
-* It dies during a I<sleep sleeptime> cycle
+created. The reason for not reusing an exising table is that the user
-* A new process B is spawned (by an unrelated process)
+may have added more input sources which would require more columns in
-* This is done during the same I<sleep sleeptime> cycle
+the table.
-* B is owned by the same user
-* B reuses the pid of the A
 
-It is considered unlikely to ever happen due to:
+The table columns are similar to joblog with the addition of B<V1>
+.. B<Vn> which are values from the input sources, and stdout and
+stderr which are the output from standard output and standard error,
+respectively.
+
+The Signal column has been renamed to _Signal due to Signal being a
+reserved word in MySQL.
 
-* The longest I<sleep sleeptime> sleeps is 10 ms
-* Re-use of a dead pid rarely happens within a few seconds
 
 
 =head1 Ideas for new design

src/sql

@@ -566,7 +566,7 @@ $Global::Initfile && unlink $Global::Initfile;
 exit ($err);
 
 sub parse_options {
-    $Global::version = 20151222;
+    $Global::version = 20160101;
     $Global::progname = 'sql';
 
     # This must be done first as this may exec myself

testsuite/tests-to-run/parallel-local-sql.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+
+export SQLITE=sqlite3:///%2Frun%2Fshm%2Fparallel.db
+export SQLITETBL=$SQLITE/parsql
+export PG=pg://tange:tange@lo/tange
+export PGTBL=$PG/parsql
+export MYSQL=mysql://tange:tange@lo/tange
+export MYSQLTBL=$MYSQL/parsql
+export PGTBL2=${PGTBL}2
+export PGTBL3=${PGTBL}3
+export PGTBL4=${PGTBL}4
+export PGTBL5=${PGTBL}5
+export T1=$(tempfile)
+export T2=$(tempfile)
+export T3=$(tempfile)
+export T4=$(tempfile)
+export T5=$(tempfile)
+export T6=$(tempfile)
+export T7=$(tempfile)
+export T8=$(tempfile)
+export T9=$(tempfile)
+export T10=$(tempfile)
+export T11=$(tempfile)
+export T12=$(tempfile)
+export T13=$(tempfile)
+export T14=$(tempfile)
+
+#sql mysql://tange:tange@lo/ 'create database tange;'; 
+cat <<'EOF' | sed -e 's/;$/; /;' | stdout parallel -vj0 -k --joblog /tmp/jl-`basename $0` -L1 | perl -pe 's/\s*\d+\.?\d+\s*/999/g;s/999e+999.\s+.\s+/999e+999|999/g;'
+echo '### --sqlandworker mysql'
+  (sleep 2; parallel --sqlworker $MYSQLTBL sleep .3\;echo >$T1) &
+  parallel --sqlandworker $MYSQLTBL sleep .3\;echo ::: {1..5} ::: {a..e} >$T2; 
+  true sort -u $T1 $T2; 
+  sql $MYSQL 'select * from parsql order by seq;'
+
+echo '### --sqlandworker postgresql'
+  (sleep 2; parallel --sqlworker $PGTBL sleep .3\;echo >$T3) &
+  parallel --sqlandworker $PGTBL sleep .3\;echo ::: {1..5} ::: {a..e} >$T4; 
+  true sort -u $T3 $T4; 
+  sql $PG 'select * from parsql order by seq;'
+
+echo '### --sqlandworker sqlite'
+  (sleep 2; parallel --sqlworker $SQLITETBL sleep .3\;echo >$T5) &
+  parallel --sqlandworker $SQLITETBL sleep .3\;echo ::: {1..5} ::: {a..e} >$T6; 
+  true sort -u $T5 $T6; 
+  sql $SQLITE 'select * from parsql order by seq;'
+
+echo '### --sqlandworker postgresql -S lo'
+  (sleep 2; parallel -S lo --sqlworker $PGTBL2 sleep .3\;echo >$T7) &
+  parallel -S lo --sqlandworker $PGTBL2 sleep .3\;echo ::: {1..5} ::: {a..e} >$T8; 
+  true sort -u $T7 $T8; 
+  sql $PG 'select * from parsql2 order by seq;'
+
+echo '### --sqlandworker postgresql --results'
+  mkdir -p /tmp/out--sql
+  (sleep 2; parallel --results /tmp/out--sql --sqlworker $PGTBL3 sleep .3\;echo >$T9) &
+  parallel --results /tmp/out--sql --sqlandworker $PGTBL3 sleep .3\;echo ::: {1..5} ::: {a..e} >$T10; 
+  true sort -u $T9 $T10; 
+  sql $PG 'select * from parsql3 order by seq;'
+
+echo '### --sqlandworker postgresql --linebuffer'
+  (sleep 2; parallel --linebuffer --sqlworker $PGTBL4 sleep .3\;echo >$T11) &
+  parallel --linebuffer --sqlandworker $PGTBL4 sleep .3\;echo ::: {1..5} ::: {a..e} >$T12; 
+  true sort -u $T11 $T12; 
+  sql $PG 'select * from parsql4 order by seq;'
+
+echo '### --sqlandworker postgresql -u'
+  (sleep 2; parallel -u --sqlworker $PGTBL5 sleep .3\;echo >$T13) &
+  parallel -u --sqlandworker $PGTBL5 sleep .3\;echo ::: {1..5} ::: {a..e} >$T14; 
+  true sort -u $T13 $T14; 
+  sql $PG 'select * from parsql5 order by seq;'
+
+EOF
+
+eval rm '$T'{1..14}