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Viewing Issue Simple Details |
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ID |
Category |
Type |
Reproducibility |
Date Submitted |
Last Update |
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0000052 |
[In-Portal CMS] Data Management |
bug report |
random |
2009-06-07 07:42 |
2009-10-03 07:56 |
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Reporter |
alex |
View Status |
public |
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Assigned To |
alex |
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Priority |
normal |
Resolution |
fixed |
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Status |
closed |
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Summary |
0000052: Preventing Data loss from Temporarily tables |
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Description |
We could lost data, when 2 concurrently running processes tries to copy data from same temporary table to live table. To prevent this I propose to implement semaphore system. Idea is to put all processes, that required temp->live operation to queue using database lock feature. |
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Additional Information |
Implementing logic:
Add new Semaphores table, that will consist of Timestamp, SessionKey and MainPrefix columns. Before temp to live coping starts open second database connection and lock Semaphores table (new table). Then we should search for any record for our prefix. When found we release lock, wait for 1 second and repeat previous steps. In case, when we totally have waited for 30 seconds, then exit from coping process with error.
If at some point we haven't found record with our prefix, then we should add one and release lock. Perform coping from temp to live. Lock Semaphores table and delete our previously added record and release lock.
This way if two (or more) temp handlers will meet, then they will wait for each other and won't start to work concurrently. |
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