Improve the last_build queries - they had got noticeably slow

diff --git a/cgi-bin/show_log.pl b/cgi-bin/show_log.pl
index 064337d882729f82cbedae043cb68e692753f1ef..22df73144db1911a26970c8ccdc73c440fe3c274 100755 (executable)
--- a/cgi-bin/show_log.pl
+++ b/cgi-bin/show_log.pl
@@ -58,16 +58,20 @@ if ($system && $logdate)
 
        };
        my $last_build_statement = q{
 
        };
        my $last_build_statement = q{

-               select distinct on (sysname) sysname, snapshot, stage, git_head_ref 
-        from build_status 
-        where sysname = ? and branch = ? and snapshot < ? 
-        order by sysname, snapshot desc limit 1
+               select git_head_ref 
+                from build_status 
+                where sysname = ? and branch = ?  and snapshot =
+                    (select max(snapshot)
+                    from build_status
+                    where sysname = ? and branch = ? and snapshot < ?)

        };
        my $last_success_statement = q{
        };
        my $last_success_statement = q{

-               select distinct on (sysname) sysname, snapshot, git_head_ref 
-        from build_status 
-        where sysname = ? and branch = ? and snapshot < ? and stage = 'OK' 
-        order by sysname, snapshot desc limit 1
+               select git_head_ref 
+                from build_status 
+                where sysname = ? and branch = ?  and snapshot =
+                    (select max(snapshot)
+                    from build_status
+                    where sysname = ? and branch = ? and snapshot < ? and stage = 'OK')

        };
        my $sth=$db->prepare($statement);
        $sth->execute($system,$logdate);
        };
        my $sth=$db->prepare($statement);
        $sth->execute($system,$logdate);


@@ -80,7 +84,7 @@ if ($system && $logdate)
        {
                $last_build_row = 
                  $db->selectrow_hashref($last_build_statement,undef,
        {
                $last_build_row = 
                  $db->selectrow_hashref($last_build_statement,undef,

-                                                                $system,$branch,$logdate);
+                                                                $system, $branch,$system,$branch,$logdate);

                $last_build_git_ref = $last_build_row->{git_head_ref}
                  if $last_build_row;
                
                $last_build_git_ref = $last_build_row->{git_head_ref}
                  if $last_build_row;
                


@@ -90,7 +94,7 @@ if ($system && $logdate)
        {
                $last_success_row =
                  $db->selectrow_hashref($last_success_statement,undef,
        {
                $last_success_row =
                  $db->selectrow_hashref($last_success_statement,undef,

-                                                                $system,$branch,$logdate);
+                                                                $system,$branch,$system,$branch,$logdate);

                $last_success_git_ref = $last_success_row->{git_head_ref}
                  if $last_success_row;
        }
                $last_success_git_ref = $last_success_row->{git_head_ref}
                  if $last_success_row;
        }