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  • Undocumented overload of string.Split() ?

    - by Neil N
    According to both Intellisense and MSDN doc on string.Split, there are no parameterless overloads of string.Split. Yet if I type in string[] foo = bar.Split(); It compiles. And it works. I have verified this in both Visual Studio 2008 and 2010. In both cases intellisense does not show the parameterless overload. Is there a reason for this? Are there any other missing overloads from the MSDN/Intellisense docs? Usually browsing through overloads in intellisense is how I best determine which overload to use. I'd hate to think I am missing other available options throughout the .Net framework.

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  • Undocumented Query Plans: Equality Comparisons

    - by Paul White
    The diagram below shows two data sets, with differences highlighted: To find changed rows using TSQL, we might write a query like this: The logic is clear: join rows from the two sets together on the primary key column, and return rows where a change has occurred in one or more data columns.  Unfortunately, this query only finds one of the expected four rows: The problem, of course, is that our query does not correctly handle NULLs.  The ‘not equal to’ operators <> and != do not evaluate...(read more)

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  • How are undocumented functions discovered?

    - by Paska
    Hi all, I've always wondered how do you find undocumented / private API ? Example the Apple undocumented / private API, Play Station, Windows Phone 7, Win32 Kernel, Windows API, hidden callback, etc... What tools do hackers use to find out about private and undocumented functions? Where can I read about peoples' experiences delving into private APIs and reverse engineering techniques which reveal the secrets which are normally explained in API documentation? thanks, A

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  • IE: Undocumented "cache" attribute defined for input elements?

    - by aefxx
    Hi everybody. I've stumpled upon a strange behavior in IE(6/7/8) that drives me nuts. Given the following markup: <input type="text" value="foo" class="bar" cache="yes" send="no" /> Please note that the cache attribute is set to yes. However IE somehow manages to change the attributes value to cache="cache" when rendering the DOM. So, I wonder, is there an undocumented feature that I'm not aware of? I've googled about an hour now but couldn't find any info on this (not even on MSDN). NOTE I'm aware that adding custom attributes is non-standard compliant and that boolean attributes should be noted as attribute="attribute. Nevertheless I have to cope with these as they were introduced long before I joined the team. These custom attributes are used in conjunction with javascript to provide a more user friendly approach to form handling (and it works out quite well with Firefox/Safari/Opera/Chrome). I know that I could simply convert these custom attributes to x-data attributes that will be introduced with HTML5 but that would take me several hours of extra work - sigh. Hope, I made myself clear. Thanks in advance.

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  • Why are so many DBCC commands undocumented?

    - by DBA
    Paul Randal of SQLskills.com does a great job of answering the question of why there are so many undocumented DBCC commands in his post Why are so many DBCC commands undocumented? I would like to go on to say that not only does this apply to the DBCC commands but is some respect to all parts of SQL, other Servers, IDE's, Operating Systems, just about everywhere. There is always something that just does not make it into the official documentation. And as Paul points out probably never will make it. That could be why there are so many "Tips & Tricks" types of books, blog post, etc. everywhere you look. And I also agree with Janos's comments on Paul's post, which was "I'm fine with them undocumented. All of us who need to use these commands know where to find "documentation" and whom to ask ". Till later,

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  • How can I use MPTVOutWindow iPhone undocumented class?

    - by Leg10n
    Hi, I'm an iPhone developer, now I'm developing a game and I just found about the iPhone 2.2 being able to reproduce video on a TV Screen trhough MPTVOutWindow class. After googling I've found a lot of blogs with the News, however none of them give any information on the class, what should I do to implement the class in order to display ouput on the TV?

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  • Qt undocumented method setSharable

    - by soxs060389
    I stumbled about a method which seems to be present in all DataObjects like QList, QQueue, QHash... I even investigated so far i can see the source code of it, which is inline void setSharable(bool sharable) { if (!sharable) detach(); d->sharable = sharable; } in qlist.h (lines 117) but what effect does it have on the QList, QQueue, QHash... ? And is it in any way related to threading? (which sounds reasonable) Thanks for any answer, and please only answer if you got actual knowledge.

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  • Are there any "undocumented features" in Silverlight?

    - by Sorskoot
    I was wondering if there are any features in Silverlight 2 or 3 that aren't documented or are hidden very deep in the framework? Stuff that can be very helpful in some cases, but can be a pain to find. Are there any "hidden" gems? I'm thinking about stuff you normaly don't find in tutorials and in demos. For example, finding information about the operating system the Silverlight Application is running on thru the System.OperatingSystem class.

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  • Undocumented Secrets of MATLAB-Java Programming, un livre de Yair Altman, critique par Jérôme Briot

    Undocumented Secrets of MATLAB-Java Programming de Yair Altman D'après l'éditeur : Citation: For a variety of reasons, the MATLAB®-Java interface was never fully documented. This is really quite unfortunate: Java is one of the most widely used programming languages, having many times the number of programmers and programming resources as MATLAB. Also unfortunate is the popular claim that while MATLAB is a fine programming platform for prototyping...

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  • Undocumented Gmail Search Operator Ferrets Out Large Email Attachments

    - by Jason Fitzpatrick
    If you’re looking for a way to quickly find large email attachments in your Gmail account, this undocumented search operator makes it simple to zero in on the hulking attachments hiding out in your inbox. To use the search operator simply plug in “size:” and some value to narrow your search to only emails that size or larger. In the screenshot above we searched for “size:20000000″ to search for files roughly 20MB or larger (if you want to be extremely precise, a true 20MB search would be “size:20971520″). If you’re looking to clean up your Gmail account this is a nearly zero-effort way to find the biggest space hogs–in our case, we found an email packed with massive PDF files from a 5 year old project that we were more than happy to purge. Finding Large Attachments in Google Mail/Gmail [via gHacks] 6 Ways Windows 8 Is More Secure Than Windows 7 HTG Explains: Why It’s Good That Your Computer’s RAM Is Full 10 Awesome Improvements For Desktop Users in Windows 8

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  • Undocumented Query Plans: The ANY Aggregate

    - by Paul White
    As usual, here’s a sample table: With some sample data: And an index that will be useful shortly: There’s a complete script to create the table and add the data at the end of this post.  There’s nothing special about the table or the data (except that I wanted to have some fun with values and data types). The Task We are asked to return distinct values of col1 and col2 , together with any one value from the thing column (it doesn’t matter which) per group.  One possible result set is shown...(read more)

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  • Training new employees on undocumented code

    - by glowcoder
    Our company has a large codebase (2500+ classes/interfaces in just the core alone, many more in other projects) for our flagship software product. We've never really hired more than one developer at a time, so we don't have a real training process. We're going to be bringing in 2-5 more developers now, and probably more in the near future (to put things into perspective, we have 7 right now.) Obviously, we would like to get these guys up to speed as soon as possible. The catch - almost all of our classes (95%+) are completely undocumented. No javadoc, no design docs, basically completely undocumented. What strategies can we employ to bring the new developers up to speed? I'd like to consider situations that include the existing code getting documented, but it's possible management won't allow for the time to get that done, so I also must consider situations where that won't happen. Has anyone been there before? What worked well for you? Thanks!

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  • MERGE Bug with Filtered Indexes

    - by Paul White
    A MERGE statement can fail, and incorrectly report a unique key violation when: The target table uses a unique filtered index; and No key column of the filtered index is updated; and A column from the filtering condition is updated; and Transient key violations are possible Example Tables Say we have two tables, one that is the target of a MERGE statement, and another that contains updates to be applied to the target.  The target table contains three columns, an integer primary key, a single character alternate key, and a status code column.  A filtered unique index exists on the alternate key, but is only enforced where the status code is ‘a’: CREATE TABLE #Target ( pk integer NOT NULL, ak character(1) NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) );   CREATE UNIQUE INDEX uq1 ON #Target (ak) INCLUDE (status_code) WHERE status_code = 'a'; The changes table contains just an integer primary key (to identify the target row to change) and the new status code: CREATE TABLE #Changes ( pk integer NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) ); Sample Data The sample data for the example is: INSERT #Target (pk, ak, status_code) VALUES (1, 'A', 'a'), (2, 'B', 'a'), (3, 'C', 'a'), (4, 'A', 'd');   INSERT #Changes (pk, status_code) VALUES (1, 'd'), (4, 'a');          Target                     Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ a           ¦    ¦  1 ¦ d           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ d           ¦ +-----------------------+ The target table’s alternate key (ak) column is unique, for rows where status_code = ‘a’.  Applying the changes to the target will change row 1 from status ‘a’ to status ‘d’, and row 4 from status ‘d’ to status ‘a’.  The result of applying all the changes will still satisfy the filtered unique index, because the ‘A’ in row 1 will be deleted from the index and the ‘A’ in row 4 will be added. Merge Test One Let’s now execute a MERGE statement to apply the changes: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; The MERGE changes the two target rows as expected.  The updated target table now contains: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦ <—changed from ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦ <—changed from ‘d’ +-----------------------+ Merge Test Two Now let’s repopulate the changes table to reverse the updates we just performed: TRUNCATE TABLE #Changes;   INSERT #Changes (pk, status_code) VALUES (1, 'a'), (4, 'd'); This will change row 1 back to status ‘a’ and row 4 back to status ‘d’.  As a reminder, the current state of the tables is:          Target                        Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ d           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ a           ¦ +-----------------------+ We execute the same MERGE statement: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; However this time we receive the following message: Msg 2601, Level 14, State 1, Line 1 Cannot insert duplicate key row in object 'dbo.#Target' with unique index 'uq1'. The duplicate key value is (A). The statement has been terminated. Applying the changes using UPDATE Let’s now rewrite the MERGE to use UPDATE instead: UPDATE t SET status_code = c.status_code FROM #Target AS t JOIN #Changes AS c ON t.pk = c.pk WHERE c.status_code <> t.status_code; This query succeeds where the MERGE failed.  The two rows are updated as expected: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ a           ¦ <—changed back to ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ d           ¦ <—changed back to ‘d’ +-----------------------+ What went wrong with the MERGE? In this test, the MERGE query execution happens to apply the changes in the order of the ‘pk’ column. In test one, this was not a problem: row 1 is removed from the unique filtered index by changing status_code from ‘a’ to ‘d’ before row 4 is added.  At no point does the table contain two rows where ak = ‘A’ and status_code = ‘a’. In test two, however, the first change was to change row 1 from status ‘d’ to status ‘a’.  This change means there would be two rows in the filtered unique index where ak = ‘A’ (both row 1 and row 4 meet the index filtering criteria ‘status_code = a’). The storage engine does not allow the query processor to violate a unique key (unless IGNORE_DUP_KEY is ON, but that is a different story, and doesn’t apply to MERGE in any case).  This strict rule applies regardless of the fact that if all changes were applied, there would be no unique key violation (row 4 would eventually be changed from ‘a’ to ‘d’, removing it from the filtered unique index, and resolving the key violation). Why it went wrong The query optimizer usually detects when this sort of temporary uniqueness violation could occur, and builds a plan that avoids the issue.  I wrote about this a couple of years ago in my post Beware Sneaky Reads with Unique Indexes (you can read more about the details on pages 495-497 of Microsoft SQL Server 2008 Internals or in Craig Freedman’s blog post on maintaining unique indexes).  To summarize though, the optimizer introduces Split, Filter, Sort, and Collapse operators into the query plan to: Split each row update into delete followed by an inserts Filter out rows that would not change the index (due to the filter on the index, or a non-updating update) Sort the resulting stream by index key, with deletes before inserts Collapse delete/insert pairs on the same index key back into an update The effect of all this is that only net changes are applied to an index (as one or more insert, update, and/or delete operations).  In this case, the net effect is a single update of the filtered unique index: changing the row for ak = ‘A’ from pk = 4 to pk = 1.  In case that is less than 100% clear, let’s look at the operation in test two again:          Target                     Changes                   Result +-----------------------+    +------------------+    +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦    ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦    ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ d           ¦    ¦  1 ¦ A  ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦    ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+    ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦                            ¦  4 ¦ A  ¦ d           ¦ +-----------------------+                            +-----------------------+ From the filtered index’s point of view (filtered for status_code = ‘a’ and shown in nonclustered index key order) the overall effect of the query is:   Before           After +---------+    +---------+ ¦ pk ¦ ak ¦    ¦ pk ¦ ak ¦ ¦----+----¦    ¦----+----¦ ¦  4 ¦ A  ¦    ¦  1 ¦ A  ¦ ¦  2 ¦ B  ¦    ¦  2 ¦ B  ¦ ¦  3 ¦ C  ¦    ¦  3 ¦ C  ¦ +---------+    +---------+ The single net change there is a change of pk from 4 to 1 for the nonclustered index entry ak = ‘A’.  This is the magic performed by the split, sort, and collapse.  Notice in particular how the original changes to the index key (on the ‘ak’ column) have been transformed into an update of a non-key column (pk is included in the nonclustered index).  By not updating any nonclustered index keys, we are guaranteed to avoid transient key violations. The Execution Plans The estimated MERGE execution plan that produces the incorrect key-violation error looks like this (click to enlarge in a new window): The successful UPDATE execution plan is (click to enlarge in a new window): The MERGE execution plan is a narrow (per-row) update.  The single Clustered Index Merge operator maintains both the clustered index and the filtered nonclustered index.  The UPDATE plan is a wide (per-index) update.  The clustered index is maintained first, then the Split, Filter, Sort, Collapse sequence is applied before the nonclustered index is separately maintained. There is always a wide update plan for any query that modifies the database. The narrow form is a performance optimization where the number of rows is expected to be relatively small, and is not available for all operations.  One of the operations that should disallow a narrow plan is maintaining a unique index where intermediate key violations could occur. Workarounds The MERGE can be made to work (producing a wide update plan with split, sort, and collapse) by: Adding all columns referenced in the filtered index’s WHERE clause to the index key (INCLUDE is not sufficient); or Executing the query with trace flag 8790 set e.g. OPTION (QUERYTRACEON 8790). Undocumented trace flag 8790 forces a wide update plan for any data-changing query (remember that a wide update plan is always possible).  Either change will produce a successfully-executing wide update plan for the MERGE that failed previously. Conclusion The optimizer fails to spot the possibility of transient unique key violations with MERGE under the conditions listed at the start of this post.  It incorrectly chooses a narrow plan for the MERGE, which cannot provide the protection of a split/sort/collapse sequence for the nonclustered index maintenance. The MERGE plan may fail at execution time depending on the order in which rows are processed, and the distribution of data in the database.  Worse, a previously solid MERGE query may suddenly start to fail unpredictably if a filtered unique index is added to the merge target table at any point. Connect bug filed here Tests performed on SQL Server 2012 SP1 CUI (build 11.0.3321) x64 Developer Edition © 2012 Paul White – All Rights Reserved Twitter: @SQL_Kiwi Email: [email protected]

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  • How to check any undocumented methods provided by apple?

    - by Mahbubur R Aaman
    The following tools is provided by Apple dlopen dlsym objc_getClass sel_registerName objc_msgSend Those are listing Objective-C selectors, or strings. Objective-C selectors are stored in a special region of the binary, and therefore Apple could extract the content from there, and check if you've used some undocumented Objective-C methods. How to utilize these tools to find undocumented Objective-C methods? EDIT: Recently, one of my App rejected due to using one undocumented methods. -[UIDevice setOrientation] Since, selectors are independent from the class you're messaging, even if my custom class defines -setOrientation: irrelevant to UIDevice, there will be a possbility of being rejected.

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  • Compute Scalars, Expressions and Execution Plan Performance

    - by Paul White
    The humble Compute Scalar is one of the least well-understood of the execution plan operators, and usually the last place people look for query performance problems. It often appears in execution plans with a very low (or even zero) cost, which goes some way to explaining why people ignore it. Some readers will already know that a Compute Scalar can contain a call to a user-defined function, and that any T-SQL function with a BEGIN…END block in its definition can have truly disastrous consequences...(read more)

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  • Temporary Tables in Stored Procedures

    - by Paul White
    Ask anyone what the primary advantage of temporary tables over table variables is, and the chances are they will say that temporary tables support statistics and table variables do not. This is true, of course; even the indexes that enforce PRIMARY KEY and UNIQUE constraints on table variables do not have populated statistics associated with them, and it is not possible to manually create statistics or non-constraint indexes on table variables. Intuitively, then, any query that has alternative execution...(read more)

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  • Deletes that Split Pages and Forwarded Ghosts

    - by Paul White
    Can DELETE operations cause pages to split? Yes. It sounds counter-intuitive on the face of it; deleting rows frees up space on a page, and page splitting occurs when a page needs additional space. Nevertheless, there are circumstances when deleting rows causes them to expand before they can be deleted. The mechanism at work here is row versioning (extract from Books Online below): Isolation Levels The relationship between row-versioning isolation levels (the first bullet point) and page splits is...(read more)

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  • Apache virtual server httpd-vhosts undocumented issue

    - by Ethon Bridges
    I have read the Apache documentation on the https-vhosts.conf file and after a couple of hours fighting this problem, figured it out on my own. Here's the situation: We have a domain that ends in a .ws Apparently you can't do this in the conf file. You MUST use the ? wildcard or it will not work. The * wildcard will not work either. Further, in the ServerAlias directive, anything past the first entry will not work if the first entry in the ServerAlias directive is not correct. Here is an example of an entry that does NOT work. Note that anotherdomain.com and yetanotherdomain.com will fail because thedomain.ws is not configured correctly: <VirtualHost *:80> DocumentRoot /opt/local/apache2/sites/ourdomain ServerName www.thedomain.ws ServerAlias thedomain.ws another domain.com yetanotherdomain.com <Directory /opt/local/apache2/sites/ourdomain> allow from all </Directory> </VirtualHost> Here is an example of our working entry: <VirtualHost *:80> DocumentRoot /opt/local/apache2/sites/ourdomain ServerName www.thedomain.ws? ServerAlias thedomain.ws? another domain.com yetanotherdomain.com <Directory /opt/local/apache2/sites/ourdomain> allow from all </Directory> </VirtualHost> If there is documentation of this, I sure didn't see it.

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  • Undocumented AS3 API

    - by grayger
    Recently, I happen to know MovieClip.addFrameScript() which is very useful, otherwise timeline script should be coded in fla. Do you know any other undocumented Actionscript3 API?

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  • T-SQL Tuesday #33: Trick Shots: Undocumented, Underdocumented, and Unknown Conspiracies!

    - by Most Valuable Yak (Rob Volk)
    Mike Fal (b | t) is hosting this month's T-SQL Tuesday on Trick Shots.  I love this choice because I've been preoccupied with sneaky/tricky/evil SQL Server stuff for a long time and have been presenting on it for the past year.  Mike's directives were "Show us a cool trick or process you developed…It doesn’t have to be useful", which most of my blogging definitely fits, and "Tell us what you learned from this trick…tell us how it gave you insight in to how SQL Server works", which is definitely a new concept.  I've done a lot of reading and watching on SQL Server Internals and even attended training, but sometimes I need to go explore on my own, using my own tools and techniques.  It's an itch I get every few months, and, well, it sure beats workin'. I've found some people to be intimidated by SQL Server's internals, and I'll admit there are A LOT of internals to keep track of, but there are tons of excellent resources that clearly document most of them, and show how knowing even the basics of internals can dramatically improve your database's performance.  It may seem like rocket science, or even brain surgery, but you don't have to be a genius to understand it. Although being an "evil genius" can help you learn some things they haven't told you about. ;) This blog post isn't a traditional "deep dive" into internals, it's more of an approach to find out how a program works.  It utilizes an extremely handy tool from an even more extremely handy suite of tools, Sysinternals.  I'm not the only one who finds Sysinternals useful for SQL Server: Argenis Fernandez (b | t), Microsoft employee and former T-SQL Tuesday host, has an excellent presentation on how to troubleshoot SQL Server using Sysinternals, and I highly recommend it.  Argenis didn't cover the Strings.exe utility, but I'll be using it to "hack" the SQL Server executable (DLL and EXE) files. Please note that I'm not promoting software piracy or applying these techniques to attack SQL Server via internal knowledge. This is strictly educational and doesn't reveal any proprietary Microsoft information.  And since Argenis works for Microsoft and demonstrated Sysinternals with SQL Server, I'll just let him take the blame for it. :P (The truth is I've used Strings.exe on SQL Server before I ever met Argenis.) Once you download and install Strings.exe you can run it from the command line.  For our purposes we'll want to run this in the Binn folder of your SQL Server instance (I'm referencing SQL Server 2012 RTM): cd "C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn" C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn> strings *sql*.dll > sqldll.txt C:\Program Files\Microsoft SQL Server\MSSQL11\MSSQL\Binn> strings *sql*.exe > sqlexe.txt   I've limited myself to DLLs and EXEs that have "sql" in their names.  There are quite a few more but I haven't examined them in any detail. (Homework assignment for you!) If you run this yourself you'll get 2 text files, one with all the extracted strings from every SQL DLL file, and the other with the SQL EXE strings.  You can open these in Notepad, but you're better off using Notepad++, EditPad, Emacs, Vim or another more powerful text editor, as these will be several megabytes in size. And when you do open it…you'll find…a TON of gibberish.  (If you think that's bad, just try opening the raw DLL or EXE file in Notepad.  And by the way, don't do this in production, or even on a running instance of SQL Server.)  Even if you don't clean up the file, you can still use your editor's search function to find a keyword like "SELECT" or some other item you expect to be there.  As dumb as this sounds, I sometimes spend my lunch break just scanning the raw text for anything interesting.  I'm boring like that. Sometimes though, having these files available can lead to some incredible learning experiences.  For me the most recent time was after reading Joe Sack's post on non-parallel plan reasons.  He mentions a new SQL Server 2012 execution plan element called NonParallelPlanReason, and demonstrates a query that generates "MaxDOPSetToOne".  Joe (formerly on the Microsoft SQL Server product team, so he knows this stuff) mentioned that this new element was not currently documented and tried a few more examples to see what other reasons could be generated. Since I'd already run Strings.exe on the SQL Server DLLs and EXE files, it was easy to run grep/find/findstr for MaxDOPSetToOne on those extracts.  Once I found which files it belonged to (sqlmin.dll) I opened the text to see if the other reasons were listed.  As you can see in my comment on Joe's blog, there were about 20 additional non-parallel reasons.  And while it's not "documentation" of this underdocumented feature, the names are pretty self-explanatory about what can prevent parallel processing. I especially like the ones about cursors – more ammo! - and am curious about the PDW compilation and Cloud DB replication reasons. One reason completely stumped me: NoParallelHekatonPlan.  What the heck is a hekaton?  Google and Wikipedia were vague, and the top results were not in English.  I found one reference to Greek, stating "hekaton" can be translated as "hundredfold"; with a little more Wikipedia-ing this leads to hecto, the prefix for "one hundred" as a unit of measure.  I'm not sure why Microsoft chose hekaton for such a plan name, but having already learned some Greek I figured I might as well dig some more in the DLL text for hekaton.  Here's what I found: hekaton_slow_param_passing Occurs when a Hekaton procedure call dispatch goes to slow parameter passing code path The reason why Hekaton parameter passing code took the slow code path hekaton_slow_param_pass_reason sp_deploy_hekaton_database sp_undeploy_hekaton_database sp_drop_hekaton_database sp_checkpoint_hekaton_database sp_restore_hekaton_database e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\hkproc.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\matgen.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\matquery.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\sqlmeta.cpp e:\sql11_main_t\sql\ntdbms\hekaton\sqlhost\sqllang\resultset.cpp Interesting!  The first 4 entries (in red) mention parameters and "slow code".  Could this be the foundation of the mythical DBCC RUNFASTER command?  Have I been passing my parameters the slow way all this time? And what about those sp_xxxx_hekaton_database procedures (in blue)? Could THEY be the secret to a faster SQL Server? Could they promise a "hundredfold" improvement in performance?  Are these special, super-undocumented DIB (databases in black)? I decided to look in the SQL Server system views for any objects with hekaton in the name, or references to them, in hopes of discovering some new code that would answer all my questions: SELECT name FROM sys.all_objects WHERE name LIKE '%hekaton%' SELECT name FROM sys.all_objects WHERE object_definition(OBJECT_ID) LIKE '%hekaton%' Which revealed: name ------------------------ (0 row(s) affected) name ------------------------ sp_createstats sp_recompile sp_updatestats (3 row(s) affected)   Hmm.  Well that didn't find much.  Looks like these procedures are seriously undocumented, unknown, perhaps forbidden knowledge. Maybe a part of some unspeakable evil? (No, I'm not paranoid, I just like mysteries and thought that punching this up with that kind of thing might keep you reading.  I know I'd fall asleep without it.) OK, so let's check out those 3 procedures and see what they reveal when I search for "Hekaton": sp_createstats: -- filter out local temp tables, Hekaton tables, and tables for which current user has no permissions -- Note that OBJECTPROPERTY returns NULL on type="IT" tables, thus we only call it on type='U' tables   OK, that's interesting, let's go looking down a little further: ((@table_type<>'U') or (0 = OBJECTPROPERTY(@table_id, 'TableIsInMemory'))) and -- Hekaton table   Wellllll, that tells us a few new things: There's such a thing as Hekaton tables (UPDATE: I'm not the only one to have found them!) They are not standard user tables and probably not in memory UPDATE: I misinterpreted this because I didn't read all the code when I wrote this blog post. The OBJECTPROPERTY function has an undocumented TableIsInMemory option Let's check out sp_recompile: -- (3) Must not be a Hekaton procedure.   And once again go a little further: if (ObjectProperty(@objid, 'IsExecuted') <> 0 AND ObjectProperty(@objid, 'IsInlineFunction') = 0 AND ObjectProperty(@objid, 'IsView') = 0 AND -- Hekaton procedure cannot be recompiled -- Make them go through schema version bumping branch, which will fail ObjectProperty(@objid, 'ExecIsCompiledProc') = 0)   And now we learn that hekaton procedures also exist, they can't be recompiled, there's a "schema version bumping branch" somewhere, and OBJECTPROPERTY has another undocumented option, ExecIsCompiledProc.  (If you experiment with this you'll find this option returns null, I think it only works when called from a system object.) This is neat! Sadly sp_updatestats doesn't reveal anything new, the comments about hekaton are the same as sp_createstats.  But we've ALSO discovered undocumented features for the OBJECTPROPERTY function, which we can now search for: SELECT name, object_definition(OBJECT_ID) FROM sys.all_objects WHERE object_definition(OBJECT_ID) LIKE '%OBJECTPROPERTY(%'   I'll leave that to you as more homework.  I should add that searching the system procedures was recommended long ago by the late, great Ken Henderson, in his Guru's Guide books, as a great way to find undocumented features.  That seems to be really good advice! Now if you're a programmer/hacker, you've probably been drooling over the last 5 entries for hekaton (in green), because these are the names of source code files for SQL Server!  Does this mean we can access the source code for SQL Server?  As The Oracle suggested to Neo, can we return to The Source??? Actually, no. Well, maybe a little bit.  While you won't get the actual source code from the compiled DLL and EXE files, you'll get references to source files, debugging symbols, variables and module names, error messages, and even the startup flags for SQL Server.  And if you search for "DBCC" or "CHECKDB" you'll find a really nice section listing all the DBCC commands, including the undocumented ones.  Granted those are pretty easy to find online, but you may be surprised what those web sites DIDN'T tell you! (And neither will I, go look for yourself!)  And as we saw earlier, you'll also find execution plan elements, query processing rules, and who knows what else.  It's also instructive to see how Microsoft organizes their source directories, how various components (storage engine, query processor, Full Text, AlwaysOn/HADR) are split into smaller modules. There are over 2000 source file references, go do some exploring! So what did we learn?  We can pull strings out of executable files, search them for known items, browse them for unknown items, and use the results to examine internal code to learn even more things about SQL Server.  We've even learned how to use command-line utilities!  We are now 1337 h4X0rz!  (Not really.  I hate that leetspeak crap.) Although, I must confess I might've gone too far with the "conspiracy" part of this post.  I apologize for that, it's just my overactive imagination.  There's really no hidden agenda or conspiracy regarding SQL Server internals.  It's not The Matrix.  It's not like you'd find anything like that in there: Attach Matrix Database DM_MATRIX_COMM_PIPELINES MATRIXXACTPARTICIPANTS dm_matrix_agents   Alright, enough of this paranoid ranting!  Microsoft are not really evil!  It's not like they're The Borg from Star Trek: ALTER FEDERATION DROP ALTER FEDERATION SPLIT DROP FEDERATION   #tsql2sday

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  • iPhone App rejected because of Three20 private API undocumented, private UITouch instance variables:

    - by Sijo
    I got a notification mail after submitting to app store.. "During our review of your application we found it is using private APIs, which is in violation of the iPhone Developer Program License Agreement section 3.3.1; "3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs." While your application has not been rejected, it would be appropriate to resolve this issue in your next update. The non-public APIs that are included in your application are the following undocumented, private UITouch instance variables: firstResponder UITouch._locationInWindow UITouch._phase UITouch._previousLocationInWindow UITouch._tapCount UITouch._timestamp UITouch._touchFlags UITouch._view UITouch._window Please resolve this issue in your next update to Application " . My application contains Three20. These variables are used in "UIViewAdditions.m". Is there any way to resolve this issue ? Please help me. Thanks in advance

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  • Undocumented Mac Calls

    - by Brian Postow
    I'm working on a couple of mac products, and in order to do what I need to do, I'm using some calls to undocumented methods on Mac Classes. Like IKImageView's doRotate:(id) and PDFDocument's (NSPrintOperation *)getPrintOperationForPrintInfo:(NSPrintInfo *)printInfo autoRotate:(BOOL)doRotate; How common is it for Objective C programmers to use methods like this? How do you find out about them (other than Google)? How dangerous is it to use them? Is there a danger other than that Apple will make them no-longer available in some future rev, and so your program will break?

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