Today (Actually yesterday cause 12 am was passed) I feel very ashamed of failing the test. To express this feeling in English, I had confusion  about shame and ashamed.

I feel ashamed 

- I feel almost ashamed that I've been so lucky

I'm ashamed 

- I'm ashamed to say that I liked to her

Have you no shame?

You have shamed your family.

shame is noun and verb but ashamed is adjective. That's the point that I need to keep in mind.

* 종교 : Religion!

The following diagram shows three different memory categories that server allocates.

Now check each item in more detail.

Query Cache

The query cache stores results of SELECT queries so that if the identical query is received in future, the results can be quickly returned.

Queries are examined in a case-sensitive manner, so

SELECT * FROM t

is different to 

select * from t

Comments are also considered and can make the queries differ, so

/* retry */ SELECT * FROM t

is different to

/* retry 2 */ SELECT * FROM t

Thread cache

By default, connection manager threads associate each client connection with a thread dedicated to it that handles authentication and request processing for that connection. Manager threads create a new thread when necessary but try to avoid doing so by consulting the thread cache first to see whether it contains a thread that can be used for the connection. When a connection ends, its thread is returned to the thread cache if the cache is not full.

The thread cache has a size determined by the thread_cache_size system variable. The default value is 0 (no caching), which causes a thread to be set up for each new connection and disposed of when the connection terminates.

(http://dev.mysql.com/doc/refman/5.5/en/connection-threads.html)

** I need to write more items that were not covered here **

Both MyISAM and InnoDB tablespaces are binary portable from one host to another if two conditions are met:

• Both machines must use two's-complement integer arithmetic
• Both machines must use IEEE floating-point format or else the tables must contain no floating-point columns (FLOAT or DOUBLE)

[mysqld]
lower_case_table_names=1

To sum up,

MyIsam 

• Both machines must use two's-complement integer arithmetic
• Both machines must use IEEE floating-point format or else the tables must contain no floating-point columns (FLOAT or DOUBLE)

Implicitly set locks are locks set and released on behalf of the client, by the server.

On behalf of the department I would like to thank you all

~ 를 대신하여, ~를 대표하여

A dirty read occurs when a transaction is allowed to read data from a row that has been modified by another running transaction and not yet committed.

A non-repeatable read occurs, when during the course of a transaction, a row is retrieved twice and the values within the row differ between reads.

A phantom read occurs when, in the course of a transaction, two identical queries are executed, and the collection of rows returned by the second query is different from the first. The phantom reads anomaly is a special case of Non-repeatable reads.

The following command will show:

To get query execution plan, explain is used. but not just for this, explain is more useful to get the table information such as column list and its detail.

mysql> explain [schema_name].[table_name]

or

mysql > explain table_name

+-------------+----------+------+-----+---------+----------------+
| Field       | Type     | Null | Key | Default | Extra          |
+-------------+----------+------+-----+---------+----------------+
| ID          | int(11)  | NO   | PRI | NULL    | auto_increment |
| Name        | char(35) | NO   |     |         |                |
| CountryCode | char(3)  | NO   |     |         |                |
| District    | char(20) | NO   |     |         |                |
| Population  | int(11)  | NO   |     | 0       |                |
+-------------+----------+------+-----+---------+----------------+
5 rows in set (0.01 sec)

describe is same with this.

+-----------------+---------------------+------+-----+---------+-------+
| Field           | Type                | Null | Key | Default | Extra |
+-----------------+---------------------+------+-----+---------+-------+
| TABLE_CATALOG   | varchar(512)        | NO   |     |         |       |
| TABLE_SCHEMA    | varchar(64)         | NO   |     |         |       |
| TABLE_NAME      | varchar(64)         | NO   |     |         |       |
| TABLE_TYPE      | varchar(64)         | NO   |     |         |       |
| ENGINE          | varchar(64)         | YES  |     | NULL    |       |
| VERSION         | bigint(21) unsigned | YES  |     | NULL    |       |
| ROW_FORMAT      | varchar(10)         | YES  |     | NULL    |       |
| TABLE_ROWS      | bigint(21) unsigned | YES  |     | NULL    |       |
| AVG_ROW_LENGTH  | bigint(21) unsigned | YES  |     | NULL    |       |
| DATA_LENGTH     | bigint(21) unsigned | YES  |     | NULL    |       |
| MAX_DATA_LENGTH | bigint(21) unsigned | YES  |     | NULL    |       |
| INDEX_LENGTH    | bigint(21) unsigned | YES  |     | NULL    |       |
| DATA_FREE       | bigint(21) unsigned | YES  |     | NULL    |       |
| AUTO_INCREMENT  | bigint(21) unsigned | YES  |     | NULL    |       |
| CREATE_TIME     | datetime            | YES  |     | NULL    |       |
| UPDATE_TIME     | datetime            | YES  |     | NULL    |       |
| CHECK_TIME      | datetime            | YES  |     | NULL    |       |
| TABLE_COLLATION | varchar(32)         | YES  |     | NULL    |       |
| CHECKSUM        | bigint(21) unsigned | YES  |     | NULL    |       |
| CREATE_OPTIONS  | varchar(255)        | YES  |     | NULL    |       |
| TABLE_COMMENT   | varchar(2048)       | NO   |     |         |       |
+-----------------+---------------------+------+-----+---------+-------+
21 rows in set (0.01 sec)

Source: https://github.com/waf/WCF-Binary-Message-Inspector

BinaryMessageFiddlerExtension.dll

WCF Binary Message Inspector

This is a modification of the WCF Binary Message Inspector. It provides two notable enhancements:

Uses a collapsible tree view instead of a textarea to display the decoded WCF binary message.
Allows editing and reissuing of captured WCF binary messages (thanks to HofmaDresu)

Installation for Fiddler2

Copy the file BinaryMessageFiddlerExtension/bin/Release/BinaryMessageFiddlerExtension.dll (direct download) into C:\Program Files\Fiddler2\Inspectors and restart Fiddler.

Installation for Fiddler4 (Beta)

Copy the file BinaryMessageFiddlerExtension/bin/Release/BinaryMessageFiddlerExtension_Fiddler4.dll (direct download) into C:\Program Files\Fiddler2\Inspectors and restart Fiddler.

Tree View Usage

The tree view provides the following shortcuts:

Ctrl+c — Copy current node XML
Ctrl+Shift+c — Copy tree XML
Alt+→ — Expand node and all child nodes
Alt+← — Collapse node and all child nodes
Middle-click — Toggle expand/collapse of node and all child nodes

Edit Usage

Capture a WCF binary message
In the sessions list, right click on the message and choose "Unlock for editing"
Edit the request
Reissue the request using the toolbar or the session list context menu

Knife bootstrap beyond a jump host failed just showing following log:

To resolve this, change ssh config as below on the jump host:

sudo vi /etc/ssh/sshd_config

And restart ssh service.

Our project faced a very weird problem that SSH.Net cannot get the exit event after 10 minutes. Though the command was finished, SSH.Net was waiting for its completion.

The reason was caused by the time-out of the ssh session. To increase this, set it as below.

After this, it worked well.

The new MultipleMessagesPerPoll mode added to PollingDuplex in Silverlight 4, comes with some new timeouts , so I thought it would be useful to post a detailed description of how those work. Unfortunately this is not currently covered by our documentation, which is something we are looking to address in upcoming documentation refreshes.

This is a fairly advanced topic, and the default settings should work well for most customers, so only modify these if you are encountering an issue, and you are fairly confident a timeout is causing the problem. The information below applies only to the new multiple messages mode, which is activated by settingduplexMode="MultipleMessagesPerPoll" on the PollingDuplex binding or binding element.

One important thing in the text below is to differentiate between infrastructure messages (such as polls in this case) and application messages. Infrastructure messages such as polls (and poll responses) are not initiated by or surfaced to the user – they are just an implementation detail of the protocol. Application messages are messages that actually originated in the user code. They can be separated into client-to-server messages (“requests coming from client”) or server-to-client messages (“server responses to requests coming from client” and “requests coming from server”). There is no “client responses coming from server” because of the way polling works. I will try to stick to this terminology in the text below.

Most of the new timeouts live on the server. All class and member names refer to the server-side System.ServiceModel.PollingDuplex.dll that ships in the “Server” folder of the Silverlight SDK. Take a look at the following diagram for a visual explanation:

The diagram shows an incoming poll and the chunked response being returned containing application messages. The first server-to-client application message is greater than 16/32KB (16 for self-hosted PollingDuplex services, 32KB for IIS-hosted), so the chunked response is flushed and the message should arrive immediately at the client. The then client sends a smaller application messages, but the total size does not reach 16/32KB, so the chunked response is not flushed. To prevent the message from getting stuck, the chunked response will be flushed and closed when the MaxOutputDelay timer expires, and the message will then be delivered to the client. Then the client sends two application messages coming in from the client and the timeouts associated with those.

Here is a more detailed description of each timeout.

ServerPollTimeout

• Set it here
  • System.ServiceModel.PollingDuplexHttpBinding.ServerPollTimeout
  • System.ServiceModel.Channels.PollingDuplexBindingElement.ServerPollTimeout
• Definition: Time the server holds the poll request prior to sending an empty poll response to the client. After the first outgoing server-to-client application message (either server response to request coming from client or request coming from the server) gets sent, this timer stops being used, andMaxOutputDelay kicks in. Bound to the client dispatcher (HTTP request / response)
• Default: 15 s

MaxOutputDelay

• Set it here
  • System.ServiceModel.PollingDuplexHttpBinding.MaxOutputDelay
  • System.ServiceModel.Channels.PollingDuplexBindingElement.MaxOutputDelay
• Definition: Time between the last outgoing server-to-client application message and the HTTP response being closed; it’s reset with each new outgoing message being dequeued. Closing the response ensures that all messages are flushed and no message will take longer than MaxOutputDelay to be delivered to the client. Bound to the client dispatcher.
• Default: 200 ms

PollHeartbeatTimeout

• Not settable – this is an internal property
• Definition: Timer which is started when a poll response is sent to the client, and stopped when the next poll for that dispatcher is received. Bound to the client dispatcher. If the timeout is reached, all the channels bound to the dispatcher are faulted. This is how we determine if a client “is still there”.
• Value: 4 * ServerPollTimeout + 30 s (after polling has started), 2 * ServerPollTimeout + 15 s (if server has not received the first poll from the client)

InactivityTimeout

• Set it here
  • System.ServiceModel.PollingDuplexHttpBinding.InactivityTimeout
  • System.ServiceModel.Channels.PollingDuplexBindingElement.InactivityTimeout
• Definition: Timer which is reset when an application messages is received by the channel. If the timeout is reached, the channel is faulted. Bound to the client session. Note that this not affected by polls, contrary to the way this same timeout behaves with infrastructure messages on other bindings (as described here). So effectively this is the same as ReceiveTimeout.
• Default: 10 min

ReceiveTimeout

• Set it here
  • System.ServiceModel.Channels.Binding.ReceiveTimeout
• Definition: Timer which is reset when the ServiceModel layer pumps an application message from a PollingDuplex channel. If the timeout is reached, the channel is aborted. Infrastructure messages such as polls don’t affect this timeout. Bound to the client session (channel).
• Default: 10 min

On the client side, we also have some timeouts that may be of interest. All class and member names below refer to the client-side System.ServiceModel.PollingDuplex.dll that ships in the “Client” folder of the Silverlight SDK.

ClientPollTimeout

• Set it here
  • System.ServiceModel.Channels.PollingDuplexBindingElement.ClientPollTimeout
• Definition: Time the client will wait for a response to a poll ; if the server takes longer to respond, the client will fault the channel. This is bound to the dispatcher, so it will fault all channels in the same dispatcher.
• Default: 5 min

InactivityTimeout

• Set it here
  • System.ServiceModel.Channels.PollingDuplexBindingElement.InactivityTimout
• Definition: Timer that is reset when an application message is received on the client. Bound to the session.
• Default: 10 min

Hope this is useful.

The following link shows the detailed information about wcf web.config configuration. 

http://msdn.microsoft.com/en-us/library/ms731734(v=vs.110).aspx

The tip to search for msdn site, use "site:" option on Google.

Additionally silverlight configuration schema site is as below:

http://msdn.microsoft.com/ko-kr/library/dd547083(v=vs.95).aspx

Using compgen can list all available commands in Linux.

Using grep command together, you can extract some command to find.

To list all the bash shell aliases available,

Reference: http://www.cyberciti.biz/open-source/command-line-hacks/compgen-linux-command/

Really I did ridiculous thing. 

Our system showed "Server too busy" exception so I wanted to trace the log messages of the WCF services. I followed lots of instructions for that. 

And the critical thing was as below:

  <sharedListeners>
    <add name="xml"
         type="System.Diagnostics.XmlWriterTraceListener"
               initializeData="C:\logs\Traces.svclog" />
  </sharedListeners>

After restarting our service, I refreshed the windows explorer to check if the log file was created but it didn't. 

The reason was very simple. The log file couldn't be created if the destination folder does not exist. So only after creating the 'c:\logs' folder, my concern was removed.

MSDN offers the recommended settings for tracing and message logging

(http://msdn.microsoft.com/en-us/library/aa702726(v=vs.110).aspx)

• Recommnded Settings for a Production Environment

<configuration>
 <system.diagnostics>
  <sources>
    <source name="System.ServiceModel"
            switchValue="Warning"
            propagateActivity="true" >
      <listeners>
        <add name="xml"/>
      </listeners>
    </source>
    <source name="myUserTraceSource"
            switchValue="Warning, ActivityTracing">
      <listeners>
        <add name="xml"/>
      </listeners>
    </source>
  </sources>
  <sharedListeners>
    <add name="xml"
         type="System.Diagnostics.XmlWriterTraceListener"
               initializeData="C:\logs\Traces.svclog" />
  </sharedListeners>
 </system.diagnostics>

<system.serviceModel>
  <diagnostics wmiProviderEnabled="true">
  </diagnostics>
 </system.serviceModel>
</configuration>

• Recommended Settings for Deployment or Debugging

configuration>
 <system.diagnostics>
  <sources>
    <source name="System.ServiceModel"
            switchValue="Information, ActivityTracing"
            propagateActivity="true" >
      <listeners>
        <add name="xml"/>
      </listeners>
    </source>
    <source name="System.ServiceModel.MessageLogging">
      <listeners>
        <add name="xml"/>
      </listeners>
    </source>
    <source name="myUserTraceSource"
            switchValue="Information, ActivityTracing">
      <listeners>
        <add name="xml"/>
      </listeners>
    </source>
  </sources>
  <sharedListeners>
    <add name="xml"
         type="System.Diagnostics.XmlWriterTraceListener"
               initializeData="C:\logs\Traces.svclog" />
  </sharedListeners>
 </system.diagnostics>

 <system.serviceModel>
  <diagnostics wmiProviderEnabled="true">
      <messageLogging 
           logEntireMessage="true" 
           logMalformedMessages="true"
           logMessagesAtServiceLevel="true" 
           logMessagesAtTransportLevel="true"
           maxMessagesToLog="3000" 
       />
  </diagnostics>
 </system.serviceModel>
</configuration>

(http://msdn.microsoft.com/en-us/library/ms732023(v=vs.110).aspx)

The following links are very helpful to figure out the problem that shows "NotFound" errors in Silverlight.

Dealing with those pesky WCF CommunicationException “NotFound” errors in Silverlight

http://blogs.msdn.com/b/silverlightws/archive/2010/04/15/dealing-with-those-pesky-wcf-communicationexception-notfound-errors-in-silverlight.aspx

Creating and Handling Faults in Silverlight

Configuring WCF SOAP Faults for Use with Silverlight Clients

Recently My project members and I are suffering from the problem that cannot upload and download over 30 MB file between silverlight and wcf service.

I googled lots of things and applied the suggestions but anything did not resolve our issue.

With this trouble remained I cannot sleep well so I'm writing this article now.

I searched more webs to find any hint to help us. Following sites can be helpful but the result will be known tomorrow.

http://ajaxuploader.com/large-file-upload-iis-debug.htm

This site suggests very good guide lines as below: 

1. Required

IIS7 - maxAllowedContentLength

IIS6 - maxRequestLength

2. Microsoft URL Scan

C:\WINDOWS\system32\inetsrv\urlscan\UrlScan.ini

MaxAllowedContentLength

3. File upload debug file

debug-upload.zip

http://ajaxuploader.com/large-file-upload-iis-asp-net.htm

This sites shows the required configuration for IIS7

1. Modify the maxAllowedContentLength setting in the web.config

3. Manually edit the ApplicationHost.config file

Finally to resolve this, we developed upload/download feature with new way: duplex communication on download and upload partitioning.

But this information is worth keeping in mind.

Do not forget to call Close (CloseAsync in case of Silverlight) of Proxy Service Client!

sl4_wcf_nettcp_duplex_article.zip

References:

• http://www.dotnetcurry.com/showarticle.aspx?ID=726
• http://msdn.microsoft.com/en-us/library/cc645027(v=vs.95).aspx
• http://msdn.microsoft.com/en-us/library/ee844557(v=vs.95).aspx
• http://blogs.msdn.com/b/silverlightws/archive/2010/07/16/pollingduplex-multiple-mode-timeouts-demystified.aspx
• http://blogs.msdn.com/b/silverlightws/archive/2010/04/04/some-known-wcf-issues-in-silverlight-4.aspx
• http://idunno.org/archive/2008/05/29/wcf-callbacks-a-beginners-guide.aspx
• http://msdn.microsoft.com/en-us/library/ee844556(v=vs.95).aspx

MySQL Workbench had nice feature to make SQL script to create a schema from existing database but it was not easy to find where it is.

1. Start MySQL Workbench

2. Select "Create EER Model From Existing Database" in the 'Data Modeling' section.

  (If you already have existing EER model, select it)

 * Enter required information and select Schema to reverse engineer

3. If EER Diagram is opened without any problem, Select "File > Export > Forward Engineer SQL CREATE Script..." like the following :

4. Select any option as you wish from the dialog and proceed the steps until the finish button is shown like the following. 

5. It's the SQL script we want.

Visit the following site to get more detail:

http://mkyojung.wordpress.com/2012/09/21/erwin%EC%97%90%EC%84%9C-mysql-erd-%EC%83%9D%EC%84%B1reverse-engineering/