Merge lp:~percona-toolkit-dev/percona-toolkit/pt-stalk-removes-non-empty-files-that-start-with-empty-line-1425478 into lp:~percona-toolkit-dev/percona-toolkit/release-2.2.14

[Frank Cizmich]

When "SHOW INNODB STATUS" fails for some reason, pt-stalk resorts to fetching data from /proc/<mysql_pid>/fd/<N> , where N is the file descriptor that contains innodb status data.
In that case, the first line of the collected file is empty.
pt-stalk deletes files where first line is empty.

Solved by simply increasing the number of lines checked to 10.

Note: Not sure the original intent of checking only the first line instead of whether the file is empty as a whole, ... I assume it's an efficiency issue?

[Daniel Nichter (daniel-nichter)]

Should be ok. Intent is really just to see if there's a TS line and that TS should be the first line. So that --max-count just prevents grep from going too far.

review: Approve

=== modified file 'bin/pt-stalk'
--- bin/pt-stalk	2015-01-23 10:19:56 +0000
+++ bin/pt-stalk	2015-03-27 20:03:17 +0000
@@ -1000,7 +1000,7 @@
    wait_for_subshells $OPT_RUN_TIME
    kill_all_subshells
    for file in "$d/$p-"*; do
-      if [ -z "$(grep -v '^TS ' --max-count 1 "$file")" ]; then
+      if [ -z "$(grep -v '^TS ' --max-count 10 "$file")" ]; then
          log "Removing empty file $file";
          rm "$file"
       fi