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<td class="text-paragraph-pattern-container mobile-resize-text " style="padding: 0px; border-collapse: collapse; padding: 0 0 10px 0; padding-top: 10px"> <span class="diffcontext">> This will lock the affected row(s) in the context of the current transaction such that any other concurrent writes will fail.<br><br>Will fail or it will be waiting for release? If this will fail straightaway - would it be possible to differentiate locking error from other type of error.<br>In my opinion this aproach is less than desired<br><br>- It is very specific to database (as locking may work differently in other db's)<br>- Locking is slower than other queries<br>- Complex logic to detect actual errors<br><br>> 2. Optimistic Concurrency Control The basic idea is that your records have a version or timestamp column which you fetch as part of the initial read. Then when you write the new data you add a WHERE VERSION = expected version<br><br>I kinda seen this somewhere before :)<br>This aproach sounds familiar and we kinda have this timestamp already in form of clientVersion.<br>Question is how we "framework this" that users will have this where attached. If we chain knex and always attach where to updates it could be something that will <br>help us to hide complexity. Documentation/Resolver templates could be another option.<br><br>This aproach</span> <span class="diffremovedchars" style="background-color:#ffe7e7;text-decoration:line-through;"> is way to go as</span> <span class="diffaddedchars" style="background-color:#ddfade;"> can have benefits</span> <span class="diffcontext">:<br>- It can be transformed to possibly any datasource (even the one that do not support transactions)<br>- Transactions itself will become redundant now - we can have read/write pattern.<br>- It's faster and easier to document<br>- Actual write will lock the table with other writes waiting for this to finish.</span> </td>
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