TT#145102 handle row_format mismatch (table/partition)

mariadb version > 10.1 changed the default row_format
from COMPACT to DYNAMIC. system upgraded to 7.5 therefore
end up with table partitions with different row_format, since
creating tables do not honour row_format (mysql bug 95478).

this in turn causes "ALTER TABLE .. EXCHANGE PARTITION .."
statements to fail with an error 1731 ("non matching attribute
ROW_FORMAT between table and partition", see MDEV-26027).

a manual mitigation would mean to align the row_formats
using "ALTER TABLE .. ROW_FORMAT = ..". But this in turn can
result fail with erro 1118 ("row size too large") for tables
with many&long columns (ie. accounting.cdr).

this fix will now mitigate the situation by falling back to
the built-in rowcopy method, if it detects mismatching
row_format.

Change-Id: Ief220be41b2350fa1437b6f35d46d1811facb57f
(cherry picked from commit 12de9892f8)

lib/NGCP/Cleanup.pm

@@ -256,6 +256,16 @@ sub check_table_exists {
     return $pvalue;
 }
 
+sub get_table_row_format {
+    my ($self, $table) = @_;
+
+    my ($row_format) = $self->fetch_row(
+        'information_schema', 'tables', 'row_format',
+        "where table_schema = 'accounting' and table_name = '$table'");
+
+    return $row_format;
+}
+
 sub check_partition_exists {
     my ($self, $table, $pname) = @_;
 
@@ -266,6 +276,16 @@ sub check_partition_exists {
     return $pvalue;
 }
 
+sub get_partition_row_format {
+    my ($self, $table, $pname) = @_;
+
+    my ($row_format) = $self->fetch_row(
+        'information_schema', 'innodb_sys_tables', 'row_format',
+        "where name = 'accounting/$table#P#$pname'");
+
+    return $row_format;
+}
+
 sub check_table_partitioned {
     my ($self, $table) = @_;
 
@@ -449,8 +469,15 @@ sub backup_partition {
                 # drop partitioning layout inherited from copied table creation
                 $dbh->do("alter table $mtable remove partitioning");
             }
-            $dbh->do("alter table $table exchange partition $pname with table $mtable");
-            die "Cannot exchange partition $table -> $mtable: ".$DBI::errstr if $DBI::err;
+            my $mtable_row_format = lc($self->get_table_row_format($mtable));
+            my $partition_row_format = lc($self->get_partition_row_format($table,$pname));
+            if ($mtable_row_format ne $partition_row_format) {
+                $self->info("table $mtable row_format ($mtable_row_format) differs from table $table partition $pname row_format ($partition_row_format), fallback to the table backup method");
+                $self->delete_loop($table, $bm);
+            } else {
+                $dbh->do("alter table $table exchange partition $pname with table $mtable");
+                die "Cannot exchange partition $table -> $mtable: ".$DBI::errstr if $DBI::err;
+            }
         }
     }
 }