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Story #3349

LogAggregation needs to be more fault tolerant

Added by Robert Waltz over 11 years ago. Updated over 11 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Robert Waltz
Category:
d1_log_aggregation
Start date:
2012-10-19
Due date:
2013-01-05
% Done:

100%

Story Points:
Sprint:

Description

Staging test of logAggregation failed with only 10% of records processed with the following error

[ERROR] 2012-10-06 05:43:57,221 (LogAggregatorTask:retrieve:289) LogAggregatorTask-urn:node:mnStageUCSB1 <?xml version="1.0" encoding="UTF-8"?>

class javax.net.ssl.SSLPeerUnverifiedException: peer not authenticated

regardless of the cause, logAggregation needs a more fault tolerant mechanism to harvest records.

Original Algorithm

b = begin date
e = end date
t = total record count
l = limit of records to retrieve
p = total records processed

harvestRecords()
{
do
{
recordstoProcess = queryLogRecords(b,e,l);
total = recordstoProcess.totalRecordsFound;
if (recordstoProcess.isNotEmpty()))
{
process logRecords;
// maintain the date of the last record processed
update lastLogRecordProcessedDate;
p += recordstoProcess.getCount(); //count should be <= l
}
} while (p < t);
}

First time trial with algorithm from current implementation:
05:53:09 began

22:16:49 (failed due to connection problem!)

16:23:40 total hours at time of failure: retrieved 575000 count=1000 total=2306641
By these numbers it would take 2 2/3 days to complete > 2M records

Divide and Conquer Algorithm

b = begin date
e = end date
t = total record count
l = limit insertions

// recursively recordstoProcess may become huge memory problem

retrieveLogRecords( b , e)
recordstoProcess = queryLogRecords;
if (c > l && b != e)
{
e1 = median(b,e);
recordstoProcess += retrieveLogRecords( b , e1);
recordstoProcess += retrieveLogRecords( e1, e);
}
return recordstoProcess;

// use explicit stacking mechanism and loops instead of recursion
// earliest records should always be pushed on the top of the stack;

b = earliest date to process;
e = now;
l = 5000;

harvestRecords()
{
new DateStack(b,e);
do
{
logRecords = null;
try_again = false;
try
{
logRecords = retrieveLogRecords();
} catch (exception TryAgain e) {
try_again = true;
} catch (exception SomethingBadHappened e) {
try_again=true; X number of times before giving up
}
if (logRecords.isNotEmpty)
{
process logRecords;
// maintain the date of the last record processed
update lastLogRecordProcessedDate;
}
} while (DateStack.count > 0 || try_again);

}

retrieveLogRecords()
{
(b,e) = pop DateStack();
records = queryLogRecords(b,e);
t = records.total();
if (t > l && b != e)
{
e1 = median(b,e);
push DateStack(e1,e);
push DateStack(b,e1);
throw TryAgain;
}
else
{
return records
}
}

stats of current run:

[ INFO] 2012-10-19 20:45:49,558 (DivideAndConquer:getRecords:94) retrieving from start=0

[ INFO] 2012-10-19 22:05:56,186 (DivideAndConquer:doit:80) Total Harvested Log count 575586

01:20:07 to retrieve 575586 records thus far

shows about 92% reduction in processing time


Subtasks

Task #3350: Test different algorithms to prove performance improvement and fault toleranceClosedRobert Waltz

Task #3351: Integrate new harvesting prodecure into LogAggregatorTaskClosedRobert Waltz

History

#1 Updated by Robert Waltz over 11 years ago

  • Target version changed from Sprint-2012.46-Block.6.3 to Sprint-2012.44-Block.6.2
  • Due date changed from 2012-12-01 to 2012-11-10

#2 Updated by Robert Waltz over 11 years ago

  • Due date changed from 2012-11-10 to 2012-10-27
  • Target version changed from Sprint-2012.44-Block.6.2 to Sprint-2012.41-Block.6.1

#3 Updated by Robert Waltz over 11 years ago

  • Description updated (diff)

#4 Updated by Robert Waltz over 11 years ago

  • Status changed from New to In Progress

#5 Updated by Robert Waltz over 11 years ago

  • Target version changed from Sprint-2012.41-Block.6.1 to Sprint-2012.44-Block.6.2
  • Due date changed from 2012-10-27 to 2012-11-10

#6 Updated by Robert Waltz over 11 years ago

  • Target version changed from Sprint-2012.44-Block.6.2 to Sprint-2012.50-Block.6.4
  • Due date changed from 2012-11-10 to 2013-01-05

#7 Updated by Robert Waltz over 11 years ago

  • Status changed from In Progress to Closed

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