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Making it easier to debug and test your templates

By Byrne Reese
Posted October 30, 2008, in Tips & Tricks.

Sometimes there can be nothing more frustrating than trying to troubleshoot publishing performance. Often users must resort to the brute force method of debugging, such as:

  • embedding print STDERR statements in Movable Type's source code - but how many people know how to do that?

  • blocking out huge swaths of code using the <mt:ignore> tag to hone in on the root cause - a cumbersome and time consuming process.

  • turning on performance logging - a feature whose output was intended for machines and as a result is sometimes too verbose or difficult to read by mere mortals.

To help our users find a more elegant and efficient way to debug their templates and optimize their system, we have developed a simple tool that can more quickly and effectively help users hone in on those aspects of their templates that are the bottlenecks in their publishing system. The tool is a simple command line tool that outputs four very useful things:

  1. the output from the template itself - very the accuracy of the template's output yourself.

  2. a table of all the template tags invoked by the template - this table not only shows the template tag name, but also the average time it took to process each one.

  3. total build time and total number of queries executed - when trying to find the template at the root of your performance problem, this will help you to quickly identify the outlier.

  4. a table of all the SQL statements made during the publishing process - an effective way to find the actual query that is problematic.

Check out this sample output:

<template output omitted>
Template Tag Utilization:
.----------+----------------------+--------+---------+--------+--------+-------.
| Time     | Tag                  | Calls  | Avg     | SQL    | Hits   | Miss  |
+----------+----------------------+--------+---------+--------+--------+-------+
| 0.083    | entryassets          | 20     | 0.004   | 40     | 20     | 20    |
| 0.040    | entries              | 8      | 0.005   | 12     | 16     | 4     |
| 0.027    | assetproperty        | 16     | 0.002   | 16     | 0      | 0     |
| 0.020    | include              | 6      | 0.003   | 7      | 3      | 3     |
| 0.019    | categories           | 4      | 0.005   | 5      | 20     | 5     |
| 0.014    | assetthumbnaillink   | 4      | 0.003   | 4      | 4      | 0     |
| 0.010    | keyvalues            | 4      | 0.002   | 0      | 0      | 0     |
| 0.006    | collatesetfield      | 32     | 0.000   | 0      | 0      | 0     |
| 0.004    | setvarblock          | 28     | 0.000   | 0      | 0      | 0     |
| 0.004    | gridcell             | 8      | 0.000   | 0      | 0      | 0     |
                                   -- snip--
'----------+----------------------+--------+---------+--------+--------+-------'
  Total Queries: 86
  Total Build Time: 0.261901
.------------------------------------------------------------------+-----------.
| Query                                                            | Number    |
+------------------------------------------------------------------+-----------+
| RAMCACHE_GET ?                                                   | 63        |
| RAMCACHE_ADD ?                                                   | 32        |
| SELECT asset_id FROM mt_asset, mt_objectasset WHERE (objectasse- | 20        |
| t_object_ds = ?) AND (objectasset_asset_id = asset_id) AND (obj- |           |
| ectasset_object_id = ?)                                          |           |
| SELECT asset_id, asset_blog_id, asset_class, asset_created_by, - | 20        |
| asset_created_on, asset_description, asset_file_ext, asset_file- |           |
| _name, asset_file_path, asset_label, asset_mime_type, asset_mod- |           |
| ified_by, asset_modified_on, asset_parent, asset_url FROM mt_as- |           |
| set WHERE (asset_id IN (?))                                      |           |
| SELECT asset_meta_asset_id, asset_meta_type, asset_meta_vchar, - | 20        |
| asset_meta_vchar_idx, asset_meta_vdatetime, asset_meta_vdatetim- |           |
| e_idx, asset_meta_vinteger, asset_meta_vinteger_idx, asset_meta- |           |
| _vfloat, asset_meta_vfloat_idx, asset_meta_vblob, asset_meta_vc- |           |
| lob FROM mt_asset_meta WHERE (asset_meta_asset_id = ?)           |           |
                                   -- snip--
'------------------------------------------------------------------+-----------'

Using the tool is relatively straight forward: all you need to do is give the tool the ID of the template you want to debug, in addition to any other contextual information that template might need, e.g. a category ID if you are publishing a category archive. Running the tool with the conventional --help flag will tell you all of the possible options.

Keep reading behind the cut to learn more specifically how to use this tool.

Example Usage

First, installation:

prompt> cp mt-tmpl-test /path/to/mt/tools

Now, how to get help:

prompt> cd /path/to/mt
prompt> perl ./tools/mt-tmpl-test --help
usage:  ./tools/mt-tmpl-test [template name]

    --blog <name>      Specify a blog context by blog ID or name.
    --template <name>  Specify a template to process by template ID or name.
    --category <label> Specify a category to process by category ID or label.
    --entry <title>    Specify an entry to process by entry ID or title.
    --author <name>    Specify an author to process by ID or username.
    --archive <type>   Specify a archive type.
    --profile          Enables SQL and template tag profiling.
    --debug <mode>     Sets MT's DebugMode.

And finally, how to actually use the tool:

prompt> perl ./tools/mt-tmpl-test --template=123 --profile
* output to appear here *
Back

Leave a Comment

11 Comments

John Emerson

John Emerson on October 31, 2008, 8:16 a.m. Reply

Great idea — you just need to add “require MT::TemplateMap;” for it to run.

Ryan

Ryan on September 26, 2009, 8:00 a.m. Reply

Looks like a good tool. I wonder though if non power users would be able to understand SQL commands in output.

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used cars los angeles on December 30, 2009, 12:41 p.m. Reply

Cool Gadget.

Liam Mi

Liam Mi on September 11, 2012, 12:48 p.m. Reply

Hi, can you tell me how to add “require MT::TemplateMap;” so the process to start?

Michael Roberts

Michael Roberts on September 12, 2012, 8:43 a.m. Reply

I surely don’t know how to embed print STDERR statements in Movable Type’s source code, so thank you for the new method I can use.

Petar Ivanoff

Petar Ivanoff on October 16, 2012, 12:28 a.m. Reply

Hi, Ryan. It is really a mess here. Where should I put this require MT::TemplateMap;. Sorry for probably the stupid question, but I am completely new in coding.

Mark Anthony

Mark Anthony on October 23, 2012, 12:50 a.m. Reply

I use FogBugz for finding and fixing bugs in every CMS I use. As far as I know, there is a partnership between Moveable Type and FogBugz which is a really great news for the developers.

Maria Montegro

Maria Montegro on November 2, 2012, 6:32 a.m. Reply

A very elegant and handy method to do such a complicated task :)

mali

mali on November 3, 2012, 9:02 p.m. Reply

A very good and informative post that i have come across, thanks for sharing.

Harold Monty

Harold Monty on November 7, 2012, 3:38 a.m. Reply

I look at the data you have given to us, but I have to admit I don’t understand a thing. It is much beyond my knowledge lever. If I have such problem I will simply call to the experts to help me :)

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Byrne Reese

Byrne Reese is currently the Product Manager of Movable Type at Six Apart, where previously he held positions as the Manager of Platform Technology and Product Manager for TypePad. Byrne is a huge supporter of the Movable Type user and developer community. He dedicates much of his time to promoting and educating people about Movable Type as well as building the tools and plugins for Movable Type that are showcased on Majordojo. He contributes regularly to open source; and he is an advocate for open protocols and standards like Atom and OpenID.

Website: http://profile.typekey.com/byrnereese