Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>"Storno Transactions" or "Reversing Transactions" are summarized nicely. In lots of places.</p> <p><a href="http://richardatopenbravo.blogspot.com/2010/02/way-that-transactions-are-reversed-in.html" rel="nofollow">http://richardatopenbravo.blogspot.com/2010/02/way-that-transactions-are-reversed-in.html</a></p> <p><a href="http://help.sap.com/saphelp_46b/helpdata/en/d2/6f921f415e11d182b10000e829fbfe/content.htm" rel="nofollow">http://help.sap.com/saphelp_46b/helpdata/en/d2/6f921f415e11d182b10000e829fbfe/content.htm</a></p> <p><a href="http://forum.wordreference.com/showthread.php?t=1875166" rel="nofollow">http://forum.wordreference.com/showthread.php?t=1875166</a></p> <p>Don't conflate software implementation with accounting. A reasonable implementation can get by with minimal locking. That doesn't mean anything, however. You may have earned a rebuke because the software is (a) badly designed and (b) requires careful locking because of poor design. </p> <blockquote> <p>What are the possible issues...?</p> </blockquote> <p>Since we don't know how well or how poorly the software is written, it's impossible to guess. They may know something about their system that you didn't know.</p> <p>A simple storno transaction system <em>should</em> be easy to implement. Indeed, it <em>should</em> be trivial. </p> <p>A pair of "insert-only" tables can still encounter deadlocks if page-level locking is used during the inserts. </p> <p>Table A, page 1 has an insert in transaction X.</p> <p>Table B, page 2 has an insert in transaction Y.</p> <p>Table B, page 2 has an insert in transaction X.</p> <p>Table A, page 1 has an insert in transaction Y. </p> <p>The only way to avoid deadlocks is to have the entire system use a single table. Or have all transactions limited to a single table. Or use a single database-wide lock. </p> <p>If you have multiple-table operations (and page-level locking) then you will still have potential deadlocks even with insert-only operations. Clearly it's rare, but still possible.</p>
    singulars
    1. This table or related slice is empty.
    1. POWhat are locking, deadlocking issues in financial operations?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USS.Lott
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POWhat are locking, deadlocking issues in financial operations?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTDownMod
    1. CO"Or use a single database-wide lock." Er, that's called a single user system. Sure, you've eleiminated deadlocks, but you've serialised all transactions.
      singulars
      1. PO
      1. USPerformanceDBA
    2. CO*... even with insert-only operations. Clearly it's rare, but still possible.* It is not "rare". Inserts cause locks at various points: the heap; index pages; when rows need to be moved. When num of users increases, blocking locks and thus deadlocks increase. It is ordinary.
      singulars
      1. PO
      1. USPerformanceDBA
    3. CO@PerformanceDBA: "SQL server will lock" is not the same as a deadlock. With a single lockable resource, deadlocks are logically impossible.
      singulars
      1. PO
      1. USS.Lott
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload