[asterisk-dev] [Code Review] 3815: Improve AstDb I/O When Updating Rows

[Michael Young]

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https://reviewboard.asterisk.org/r/3815/
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(Updated July 22, 2014, 1:56 p.m.)


Status
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This change has been marked as submitted.


Review request for Asterisk Developers.


Changes
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Committed in revision 419222


Bugs: ASTERISK-24050
    https://issues.asterisk.org/jira/browse/ASTERISK-24050


Repository: Asterisk


Description
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When updating a row, we are currently doing an INSERT OR REPLACE INTO.  The downside to this is that the row is deleted if it exists and then a new row is inserted.  So, we are hitting the disk twice.  One for the deletion and one for the insertion.

The proposed patch will attempt to do an INSERT INTO and if it fails because a row with that key exists, we will ignore that.  Then we will attempt to perform an UPDATE on the existing row.  If a record was INSERTED, the UPDATE statement will end up doing nothing.


Diffs
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  /trunk/main/db.c 418608 
  /trunk/include/asterisk/astdb.h 418608 

Diff: https://reviewboard.asterisk.org/r/3815/diff/


Testing
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Local pbx with a couple of peers.  Did see a slight I/O increase.

before patch
Re-Register  Avg. 404 ms
Register     Avg. 442 ms

after patch
Re-Register  Avg. 361.5 ms
Register     Avg. 419 ms


Thanks,

Michael Young

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