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  • Advanced Diagnostics with the MivaScript debug log

    This thread is intended to be a companion to my 2013 conference presentation on the same subject and to serve as a future repository for information about the MivaScript debug log mechanism and its use. I'll be updating the first few posts over the next couple days to include additional technical information and examples.

    Basic Information
    Debug logging is supported on MivaScript engine versions 5.10 and newer.


    Configuration: Windows
    On Windows, there is a simple configuration dialog that allows the debug log to be configured.
    debug_logging_dialog.jpg
    Mia has a single debug logging setting that is applied to all scripts. On IIS, the settings can be applied to an entire website, a directory or an individual file.


    Configuration: UNIX
    Logging functionality on UNIX is identical to Windows and is configured differently depending on which configuration library you are using.


    If using the environment-variable based configuration library, the following environment variables are used:


    MvCONFIG_LOG_FILE specifies the name of the debug log file
    MvCONFIG_LOG_LEVEL specifies the individual logging functions that should be enabled
    MvCONFIG_LOG_FILTER specifies what filtering rules, if any, are applied


    The 3.x configuration library uses the following configuration directives:
    logfile specifies the name of the debug log file
    loglevel specifies the individual logging functions that should be enabled
    logfilter specifies what filtering rules, if any, are applied


    The values for the directives are the same for either configuration library.


    Configuration: Log File
    On UNIX, the log file is always created in the mivadata directory. On Windows a full path is provided.


    Configuration: Log Level
    The log level is a bitfield, with each field controlling a single loggable item. In practice, this means that there is a particular numeric value assigned to each item and to enable multiple item you just add their numeric values together to obtain the final log level value. On Windows, the configuration dialog takes care of this for you and it is a simple matter of checking the checkboxes for the items you would like logged.


    Below is a list of the loggable items and their assigned numeric values. (This list may also be found in mivapi.h in the UNIX VM distribution packages)
    Code:
    MvCONFIG_LOG_FUNC_CALL              16          Calls to native (MivaScript) functions
    MvCONFIG_LOG_FUNC_PARAM             32          Parameters to native (MivaScript) functions
    MvCONFIG_LOG_FUNC_RETVAL            64          Return values from native (MivaScript) functions
    MvCONFIG_LOG_FUNC_RETURN            128         Return from native (MivaScript) functions
    MvCONFIG_LOG_EXTERNAL_FUNC_CALL     256         Calls to builtin or other external functions
    MvCONFIG_LOG_EXTERNAL_FUNC_PARAM    512         Parameters to builtin or other external functions
    MvCONFIG_LOG_EXTERNAL_FUNC_RETVAL   1024        Return values from builtin or other external functions
    MvCONFIG_LOG_EXTERNAL_FUNC_RETURN   2048        Return from builtin or other external functions
    MvCONFIG_LOG_MvDO_FILE_ENTER        4096        MvDO of an entire file has begun
    MvCONFIG_LOG_MvDO_FILE_EXIT         8192        MvDO of an entire file has ended
    MvCONFIG_LOG_MvCALL                 1048576     Logs raw request and response data for the MvCALL tag (requires v5.13)
    MvCONFIG_LOG_APPLICATION_TIMEOUT    134217728   Logs globaltimeout terminations (requires v5.13)
    MvCONFIG_LOG_RUNTIME_ERROR          268435456   All runtime errors
    MvCONFIG_LOG_FATAL_ERROR            536870912   All fatal errors
    MvCONFIG_LOG_TRACE                  1073741824  Logs each line of source code executed
    Using the list above, if you wanted to enable MvCALL and Application Timeout logging, you would add their two values together. 1048576+134217728= 135266304, so you would use the value 135266304 for your log level.


    Configuration: Log Filter
    In v5.13 or higher, you may apply an additional filter to the debug log to limit the log messages to those that were generated by particular source code. When a filter is specified, only those lines of code which match the filter will be logged.


    The log filter directive takes the following form:
    sourcefile[:[start_line][-[end_line]],...


    "sourcefile" corresponds to the name of the MivaScript source file. This is generally the exact value that was passed to the MivaScript compiler when the source code was compiled.
    "start_line" and "end_line" refer to source code line numbers within the source file. A range may be specified like this: "1-10". Within a range, either the start or end may be omitted. For example, "-100" means lines 1-100 and "100-" means lines 100 through the end of the file.


    Source filenames and line numbers will generally be determined by examining the source code being debugged. However, they may also be inferred by generating a debug log without a filter and gathering sourcefile and line number values from the log.


    Multiple filters may be specified by separating them with a comma.


    v5.17 extends the filtering mechanism to add the concept of an exclusionary filter. By preceeding the filter value with "!", its function is reversed and any lines of code that do NOT match the filter are logged. Inclusionary and exclusionary filters may be combined, and will be applied in left to right order.


    Log Cookie
    The 5.18 engine will introduce a new type of filtering. Instead of (or in addition to) limiting the logging based on the source code, the log cookie setting allows you to restrict the logging to requests generated by clients containing a particular cookie value. There are two major components to the log cookie mechanism:


    1. The log cookie configuration setting. On Windows, the cookie value is configured within the same debug log settings dialog as the rest of the settings. On UNIX, it is set using the logcookie configuration directive (3.x configuration) or MvCONFIG_LOG_COOKIE environment variable (environment based configuration).
    2. The diagnostic tool which allows you to set the cookie on a target client.

    I will provide additional information and screenshots on this section after the 5.18 engine release


    Log File Format
    The log file is a tab delimited text file containing the following fields:
    Date/Time Stamp
    Process ID
    Type of Log Message
    Compiled MivaScript file path
    Source file
    Source line number
    Message-specific data (function return values, parameter values, MvCALL data, etc...)
    Last edited by burch; 03-07-13, 01:49 PM.

  • mvcov

    mvcov is a code coverage tool. Its purpose is to read a trace log and overlay a source file with information that displays which source lines correspond to executable code, which of those lines were exected and how many times each line was executed. We use this tool internally when developing test cases to ensure that all logic paths within the source code are tested. For debugging, when the source code is available, it can also be used to visualize the flow of execution.

    mvcov is a command line tool and has been bundled with the MivaScript compiler on both Windows and UNIX since v5.16. When run with the --help parameter, it outputs the following helpful text describing its command line options:
    Code:
    Usage: mvcov [options] logfile
    Options:
      --help           Display this information
      --version        Display version number and exit
      -p <pid>         Include only log lines from the specified process_id
      -b <directory>   Search for source files relative to <directory>
      -f <filename>    Generate coverage output only for source file <filename>
                       (may repeat)
      -o <output>      Write coverage to <output>

    Using mvcov
    1. Enable logging: mvcov requires a trace log to generate its output. On Windows, this means that you would check the "Source File/Line Number Trace" checkbox. On UNIX, you would set your log level to 1073741824.


    2. Generate a log file: After configuring logging, any requests made to the site being debugged will result in those requests being logged to the debug log. The trace log is extremely verbose, so if using this on a live site you absolutely must make use of one of the filtering mechanisms (or even better, the log cookie) to avoid slowing the site down or generating an enormous log file.


    3. Run mvcov: You will need the source code, log file and mvcov tool on the same system. In order to generate the overlay, mvcov needs to be able to read the source files referenced within the log. By default, it will attempt to locate the source files relative to the current directory, but you may override this behavior with the "-b" flag. It will also, by default, generate output for every source file referenced in the log, unless you specify one or more "-f filename" options to limit its output.


    In the example below, I have generated a debug log that contains output from a single run of the Miva Mia "Mazes of Miva" example. It was collected with the following settings:
    logfile=maze_coverage.log
    logfilter=maze/maze.mv
    loglevel=1073741824

    Code:
    #######:    505:<MvFUNCTION NAME = "Maze_Solve_PathCount" PARAMETERS = "maze var, x_pos, y_pos">
        507:    506:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos ] EQ -1 }">
        191:    507:        <MvFUNCTIONRETURN VALUE = 5>
    #######:    508:    </MvIF> 
          -:    509:
        316:    510:    <MvASSIGN NAME = "l.path_count"     VALUE = 0>
          -:    511:
        316:    512:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos - 1 ][ l.y_pos ] NE -1 }">    
        102:    513:        <MvASSIGN NAME = "l.path_count" VALUE = "{ l.path_count + 1 }"> 
        102:    514:    </MvIF> 
          -:    515:
        316:    516:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos + 1 ][ l.y_pos ] NE -1 }">    
        123:    517:        <MvASSIGN NAME = "l.path_count" VALUE = "{ l.path_count + 1 }"> 
        123:    518:    </MvIF> 
          -:    519:
        316:    520:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos - 1 ] NE -1 }">    
        135:    521:        <MvASSIGN NAME = "l.path_count" VALUE = "{ l.path_count + 1 }"> 
        135:    522:    </MvIF> 
          -:    523:
        316:    524:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos + 1 ] NE -1 }">    
        132:    525:        <MvASSIGN NAME = "l.path_count" VALUE = "{ l.path_count + 1 }">
        132:    526:    </MvIF>
          -:    527:
        316:    528:    <MvFUNCTIONRETURN VALUE = "{ l.path_count }">
    #######:    529:</MvFUNCTION>
          -:    530:
    #######:    531:<MvFUNCTION NAME = "Maze_Solve_FollowPath" PARAMETERS = "maze var, x_pos var, y_pos var">
        146:    532:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos ] EQ -1 }">
    #######:    533:        <MvFUNCTIONRETURN>
    #######:    534:    </MvIF>
          -:    535:
        146:    536:    <MvASSIGNARRAY NAME = "l.maze:cells" VALUE = "-1">
        146:    537:        <MvDIMENSION INDEX = "{ l.x_pos }">
        146:    538:        <MvDIMENSION INDEX = "{ l.y_pos }">
        146:    539:    </MvASSIGNARRAY>
          -:    540:
        146:    541:    <MvIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos - 1 ] NE -1 }">
         46:    542:        <MvASSIGN NAME = "l.y_pos"  VALUE = "{ l.y_pos - 1 }">
         46:    543:    <MvELSEIF EXPR = "{ l.maze:cells[ l.x_pos ][ l.y_pos + 1 ] NE -1 }">
         34:    544:        <MvASSIGN NAME = "l.y_pos"  VALUE = "{ l.y_pos + 1 }">
         34:    545:    <MvELSEIF EXPR = "{ l.maze:cells[ l.x_pos + 1 ][ l.y_pos ] NE -1 }">
         42:    546:        <MvASSIGN NAME = "l.x_pos"  VALUE = "{ l.x_pos + 1 }">
         42:    547:    <MvELSEIF EXPR = "{ l.maze:cells[ l.x_pos - 1 ][ l.y_pos ] NE -1  }">
         24:    548:        <MvASSIGN NAME = "l.x_pos"  VALUE = "{ l.x_pos - 1 }">
         24:    549:    </MvIF>
        146:    550:</MvFUNCTION>
    Above is a snippet of the output. The first section indicates how many times that particular line of code was executed. "#######" indicates that the line was not executed at all and "-" indicates that the line contained no executable code. Following that is the line number, then the actual source code itself.

    The attached .zip file contains the complete output from mvcov as well as the raw debug log file.
    Attached Files
    Last edited by burch; 03-07-13, 01:42 PM.

    Comment


    • mvprof

      mvprof is a profiling tool that can be used to visualize and troubleshoot the performance of MivaScript programs. When applied to Miva Merchant, it is extremely useful to diagnose slow loading pages and other odd performance problems.


      Like mvcov, it is a command line tool that has been bundled with the compiler distribution since v5.16 and will output a description of its parameters when run with --help:
      Code:
      Usage: mvprof [options] logfile
      Options:
        --help           Display this information
        --version        Display version number and exit
        -p <pid>         Include only log lines from the specified process_id
        -f <filename>    Generate profile output only for compiled file <filename>
                         (may repeat)
        -o <output>      Write output to <output>
        -M               Profile MivaScript functions only
        -B               Profile builtin functions only
        -F               Output flat profile only (suppress call graph)
        -G               Output call graph only (suppress flat profile)

      Using mvprof
      1. Enable logging: mvprof requires a log containing function call and return data to generate its output. In most cases, MivaScript functions are the ones you will be interested in profiling, so on Windows you would enable the MivaScript "Function Call" and "Function Return" options, or on UNIX would use a log level of 144. It is possible to include profiling of builtin functions as well, but you need to be careful about introducing a time bias into the profile by generating an extremely large log file.


      2. Generate a log file: After configuring logging, any requests made to the site being debugged will result in those requests being logged to the debug log. It is strongly recommended that you only attempt to capture a profile log on a live site using the 5.18 engine and the new log cookie mechanism.

      3. Run mvprof: mvprof does not require any source code. Once the log file is transferred to the system containing mvprof, executing mvprof is usually as simple as "mvprof logfile".


      In the example below, I have generated a debug log that contains output from a single request and a single source file. It was collected with the following settings:
      logfile=prod_profile.log
      loglevel=144

      In these examples I profiled the PROD page for a stock PR8 Update 2 store that had 147 configured product custom fields. This is an actual use case and the information we found from this type of profiling was used to develop the custom field performance enhancements in later PR8 updates.

      Code:
      Process 15990 flat statistics
      cumulative       self             fastest    slowest
         seconds    seconds    calls       call       call name (file)
          0.1135     0.1135      147   0.000681   0.001264 productfield_load_code (mm5/5.00/modules/util/customfld.mvc)
          0.1507     0.0371        1   0.037190   0.037190 merchant (mm5/5.00/merchant.mvc)
          0.1851     0.0344       19   0.000216   0.003527 templatemanager_initialize_item_lowlevel (mm5/5.00/features/tui/tui_mgr.mvc)
          0.2088     0.0236        2   0.000027   0.023612 templatemanager_render_json_variables (mm5/5.00/features/tui/tui_mgr.mvc)
      Above is an example of the flat statistics portion of the output log and below is an example of the call graph portion of the log.

      Code:
      Process 15990 call graph
           total       self                      fastest    slowest
         seconds    seconds       calls             call       call name (file)
          0.1242     0.1135      147/147        0.000681   0.001264     module_product_field_name (mm5/5.00/modules/util/customfld.mvc)
          0.1242     0.1135                     0.000681   0.001264 productfield_load_code (mm5/5.00/modules/util/customfld.mvc)
          0.0058     0.0058      294/300        0.000018   0.000047     db_compare_upper (mm5/5.00/lib/dbapi_mysql.mvc)
          0.0048     0.0048      147/147        0.000031   0.000055     productfield_read (mm5/5.00/modules/util/customfld.mvc)
      mvprof generates both sections for each individual logged process. The flat statistics section shows the functions that were called in the log sorted with the functions that took the longest total time at the top. In this example we can see that about 1/4 of the page's entire execution time was spent in productfield_load_code, which was called 147 times.

      The call graph section shows each function broken down with information about callers of that function and functions that it itself directly called. Indented functions above the function in question are functions that directly called that function. Indented functions below the function are functions that it called. The graph also breaks down the time spent in the various functions as well as what percentage of the calls to that function were from this source. In the example above, all 147 of the calls to productfield_load_code were made from module_product_field_name, and 294 of 300 total calls to db_compare_upper were made from productfield_load_code.

      The attached .zip file contains the raw debug log as well as the complete output from mvprof.
      Attached Files
      Last edited by burch; 03-07-13, 02:17 PM.

      Comment


      • Re: mvprof

        This sounds great, thank you for all the info!

        I'd like to use mvconf to an analyze our live site. I have SSH access to our server, but beyond that I'm not confident in what to do next. Can you confirm if these steps are even in the right ballpark?

        1. Enable logging: set the proper environment variables (in the cgi-bin conf file?):
          1. MvCONFIG_LOG_FILE (give it a filename like mvconfOutput.log for example)
          2. MvCONFIG_LOG_LEVEL - I'm not sure what level corresponds to a page load?
          3. MvCONFIG_LOG_COOKIE - not sure how to configure this cookie
        2. Generate a log file: this should be automatic based on the description?
        3. Run mvprof: will it know to use the mvconfOutput.log I set up in step 1?

        Comment


        • Re: Advanced Diagnostics with the MivaScript debug log

          First, the log cookie is not available in the currently released engine. It requires 5.18, which should be released early next week. I highly recommend you wait until you are able to upgrade to 5.18 to attempt to do any profiling of live sites because without the log cookie setting ALL requests to your site will be logged as soon as you enable the debug log. If you have a high volume site this could result in hundreds of megabytes of log data being generated.

          The following instructions assume you have heeded my warning and have your site running 5.18. If you want to live dangerously and try it on your current engine, just ignore anything having to do with the cookie:

          1. If you have a .conf file in the cgi-bin directory, you're using the 3.x configuration. You would add the following lines to the file:

          logfile=mvconfOutput.log
          loglevel=144
          logcookie=<any value you desire, should only contain letters and numbers>

          Once those lines are added to the config file, logging is enabled. If you were on a version that does not support logcookie, the log file would start growing on the very next request to your site.

          2. Use diagtool.mvc to cookie your browser with the appropriate cookie value by clicking on the "Log Cookie Status" link on the left, then "Set Log Cookie". If everything worked it should look like this:

          Screenshot from 2013-03-20 10:29.jpg

          diagtool.mvc is included with the 5.18 engine distribution or may be obtained from our Knowledge Base.

          3. Make whatever hits to your site you want to profile.

          4. Disable logging, either by removing the lines from your config file or by commenting them out (add the character "#" at the beginning of the line). I recommend doing this even if you are using logcookie.

          5. Download the log file to your local PC. It will be in your mivadata directory.

          6. Start a command prompt and run mvprof on the log file. You can use -o <outfile> to store the output in a text file (otherwise it is printed directly to the terminal).
          Last edited by burch; 03-20-13, 10:33 AM. Reason: Added diagtool screenshot and download link

          Comment


          • Re: Advanced Diagnostics with the MivaScript debug log

            that is GREAT, thank you again! I'll definitely take your advice and wait for 5.18

            Comment


            • Re: Advanced Diagnostics with the MivaScript debug log

              We've released 5.18 from development and it should be available shortly. I also updated comment #5 to include a screenshot of the relevant sections of diagtool and added a link to our Knowledge Base article where you can download the tool.

              Comment


              • Re: Advanced Diagnostics with the MivaScript debug log

                Originally posted by burch View Post
                logcookie=<any value you desire, should only contain letters and numbers>
                The above needs to be set BEFORE you try to set the cookie using diagtool.mvc (and I assume, through the Windows dialog box too).
                Bruce Golub
                Phosphor Media - "Your Success is our Business"

                Improve Your Customer Service | Get MORE Customers | Edit CSS/Javascript/HTML Easily | Make Your Site Faster | Get Indexed by Google | Free Modules | Follow Us on Facebook
                phosphormedia.com

                Comment


                • Re: Advanced Diagnostics with the MivaScript debug log

                  We do a lot of performance tweaking for sites and this could be very helpful, but getting Shell access isn't going to be easy in manny cases. Any chanced that these features could be accessed through functionality in the admin (i.e., custom module)
                  Bruce Golub
                  Phosphor Media - "Your Success is our Business"

                  Improve Your Customer Service | Get MORE Customers | Edit CSS/Javascript/HTML Easily | Make Your Site Faster | Get Indexed by Google | Free Modules | Follow Us on Facebook
                  phosphormedia.com

                  Comment


                  • Re: Advanced Diagnostics with the MivaScript debug log

                    Originally posted by Bruce - PhosphorMedia View Post
                    We do a lot of performance tweaking for sites and this could be very helpful, but getting Shell access isn't going to be easy in manny cases. Any chanced that these features could be accessed through functionality in the admin (i.e., custom module)
                    You don't need shell access, just the ability to edit mivavm.conf, which you can usually do through a control panel. The ability to change the engine configuration or enable debug logging programmatically would be a gigantic security risk, so there's no chance we'll be adding it.

                    Comment


                    • Re: Advanced Diagnostics with the MivaScript debug log

                      But how would you parse the log file? It seemed (from the instructions) that the two parsing routines where built into the engine?
                      Bruce Golub
                      Phosphor Media - "Your Success is our Business"

                      Improve Your Customer Service | Get MORE Customers | Edit CSS/Javascript/HTML Easily | Make Your Site Faster | Get Indexed by Google | Free Modules | Follow Us on Facebook
                      phosphormedia.com

                      Comment


                      • Re: Advanced Diagnostics with the MivaScript debug log

                        Originally posted by Bruce - PhosphorMedia View Post
                        But how would you parse the log file? It seemed (from the instructions) that the two parsing routines where built into the engine?
                        The log is just a text file. The mvprof and mvcov tools are part of the compiler distribution. We usually download the log files from the server and do the analysis of them locally.

                        Comment


                        • Re: Advanced Diagnostics with the MivaScript debug log

                          I am having three problems getting mvprof to work. I am on engine 5.19.

                          1. In the cgi-bin folder I do not see a .conf file. I do have a miva.conf file. Is that where I add:

                          logfile=mvconfOutput.logloglevel=144
                          logcookie=somecookievalue

                          2. Also having problem getting the shell terminal to work through plesk. It does not accept my password.

                          3. The diagtool.mvc says the logcookie is not set at the engine level.

                          I can set a cookie on my browser through firebug. I've rolled back everything for now and removed diagtool.mvc.
                          http://www.alphabetsigns.com/

                          Comment


                          • Re: Advanced Diagnostics with the MivaScript debug log

                            It sounds like you weren't editing the correct configuration file. If your site is hosted with us you can open a support ticket and we can get to the bottom of things.

                            Comment

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