Comments on: Maatkit Now Supports Memcached

By: CaptTofu

CaptTofu — Thu, 06 Aug 2009 22:43:56 +0000

Daniel,

removing the -v helped, but a later run, even without the -v, gave me the error. It was a huge dump file, and strangely, while I was doing this, my amazon instance kicked me out and wouldn’t let me back in (not related I’m sure!) So I have no way of obtaining that file that was giving me problems.

By: Daniel

Daniel — Thu, 06 Aug 2009 17:33:34 +0000

Due to loss of formatting, the above sample output is missing spaces before each hex dump line.

By: Daniel

Daniel — Thu, 06 Aug 2009 17:32:39 +0000

CaptTofu, I see you commented on http://code.google.com/p/maatkit/issues/detail?id=544 and that you fixed this by removing the -v option from tcpdump?

Currently, the tcpdump output must be like:

2009-07-04 21:33:39.229179 IP 127.0.0.1.35126 > 127.0.0.1.11211: tcp 31
0×0000: 4500 0053 1d2a 4000 4006 1f79 7f00 0001
0×0010: 7f00 0001 8936 2bcb d4c3 3924 d4c8 1de4
0×0020: 8018 0201 fe47 0000 0101 080a 0008 240b
0×0030: 0008 240b 7365 7420 6d79 5f6b 6579 2030
0×0040: 2030 2031 300d 0a53 6f6d 6520 7661 6c75
0×0050: 650d 0a

So you may need to tweak your tcpdump options to get the output correct. Any extra info will confuse the tcpdump parser and cause these kinds of errors.

By: CaptTofu

CaptTofu — Thu, 06 Aug 2009 13:10:35 +0000

Hi there!

I’m excited to try this out, but have similar problems shown here in the comments:

mk_query_digest:6758 23474 Use of uninitialized value $source in pattern match (m//) at /usr/bin/mk-query-digest line 2045, chunk 180.

Many lines of this – I even tried to make modifications to not apply the regex if not defined, but I’m not getting anywhere with it.

The tcpdump command options:

tcpdump -s 65535 -v -x -n -q -tttt -i any port 11211 > memc_tcpdump.txt

Any suggestions?

Thanks!

By: Daniel

Daniel — Mon, 03 Aug 2009 20:36:51 +0000

For those having issues parsing memcached dumps, I’ll be happy to fix them, but I’ll need a sample of your dump file that’s causing the crash. If your dump file doesn’t have private data, could you please create a new issue at http://code.google.com/p/maatkit/issues/list and upload the dump file? Else, you can email me your dump file, I’ll fix it and keep your data private; the address is my name at percona.com.

Also, if you haven’t tried the latest version already, try it: wget http://www.maatkit.org/trunk/mk-query-digest
I fixed some similar issues last week with memc parsing.

By: DLS

DLS — Mon, 03 Aug 2009 20:14:28 +0000

I also get errors:

# mk_query_digest:6758 29461 Use of uninitialized value in pattern match (m//) at mk-query-digest line 2045, chunk 2972.

Here’s how I captured tcpdump:

tcpdump -s 65535 -v -x -n -q -tttt -i any port 11211 > memc_tcpdump.txt

By: Gavin Towey

Gavin Towey — Thu, 30 Jul 2009 22:05:07 +0000

When I try to use it, it just gives lots of these lines:

./mk-query-digest –type memcached memc_tcpdump.txt

# mk_query_digest:6758 5136 tell() on closed filehandle at ./mk-query-digest line 2019.

By: Ryan

Ryan — Fri, 24 Jul 2009 22:50:52 +0000

Hey Piotr,

How’d you capture tcpdump info? Also, it doesn’t yet understand IPv6. Send Daniel the tcpdump output. And let’s put bug reports on Google Code:)

By: Piotr

Piotr — Fri, 24 Jul 2009 21:57:24 +0000

I have

root@lb2:~# ./mk-query-digest –type memcached memc_tcpdump.txt
# mk_query_digest:6381 6920 Use of uninitialized value in string eq at ./mk-query-digest line 5363, chunk 1.
#
# mk_query_digest:6381 6920 Use of uninitialized value in string eq at ./mk-query-digest line 5363, chunk 2.
#