New question #176228 on Graphite: https://answers.launchpad.net/graphite/+question/176228
I've discovered that the `stdev` function in graphite.render.functions will cause an UnboundLocalError to be triggered in some instances. Basically, it boils down to a local named sumOfSquares not being initialized on the first N items, because the average is None (the sum is None; there is no data in the first N samples). And later in the series, a non-None average appears, and uninitialized sumOfSquares is passed in doStdDev, causing the error. How can this be triggered? Well, as a simple replication case, if on the Graphite Composer you want to plot the last 24 hours, and you take the standard deviation of some metric that only has data starting 3 hours ago (ie. the data for the first 21 hours is None), then it'll blow up. -- Andrew Crowell Also, for some more diagnostics, here is a real, more complicated example, and the traceback demonstrating the problem: Environment: Request Method: GET Request URL: http://graphite2011:8888/render/?width=586&height=308&_salt=1319579730.737&from=-1days&target=movingAverage(diffSeries(load.1min.web.%5Eroll-up%2Cscale(stdev(load.1min.web.%5Eroll-up%2C50)%2C2))%2C100)&target=movingAverage(sum(load.1min.web.%5Eroll-up%2Cscale(stdev(load.1min.web.%5Eroll-up%2C50)%2C2))%2C100)&target=stdev(load.1min.web.%5Eroll-up%2C50)&target=stdev(load.1min.web.%5Eroll-up%2C50)&target=load.1min.web.%5Eroll-up&target=sumSeries(load.1min.web.%5Eroll-up%2Cscale(stdev(load.1min.web.%5Eroll-up%2C50)%2C2)) Django Version: 1.1.1 Python Version: 2.6.5 Installed Applications: ['graphite.metrics', 'graphite.render', 'graphite.cli', 'graphite.browser', 'graphite.composer', 'graphite.account', 'graphite.dashboard', 'graphite.whitelist', 'graphite.events', 'django.contrib.auth', 'django.contrib.sessions', 'django.contrib.admin', 'django.contrib.contenttypes', 'tagging'] Installed Middleware: ('django.middleware.common.CommonMiddleware', 'django.middleware.gzip.GZipMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware') Traceback: File "/usr/lib/pymodules/python2.6/django/core/handlers/base.py" in get_response 92. response = callback(request, *callback_args, **callback_kwargs) File "/opt/graphite/webapp/graphite/render/views.py" in renderView 105. seriesList = evaluateTarget(requestContext, target) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTarget 10. result = evaluateTokens(requestContext, tokens) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 21. return evaluateTokens(requestContext, tokens.expression) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 28. args = [evaluateTokens(requestContext, arg) for arg in tokens.call.args] File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 21. return evaluateTokens(requestContext, tokens.expression) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 28. args = [evaluateTokens(requestContext, arg) for arg in tokens.call.args] File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 21. return evaluateTokens(requestContext, tokens.expression) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 28. args = [evaluateTokens(requestContext, arg) for arg in tokens.call.args] File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 21. return evaluateTokens(requestContext, tokens.expression) File "/opt/graphite/webapp/graphite/render/evaluator.py" in evaluateTokens 29. return func(requestContext, *args) File "/opt/graphite/webapp/graphite/render/functions.py" in stdev 1071. (sd, sumOfSquares) = doStdDev(sumOfSquares, toDrop, series[index+time], time, avg) Exception Type: UnboundLocalError at /render/ Exception Value: local variable 'sumOfSquares' referenced before assignment You received this question notification because you are a member of graphite-dev, which is an answer contact for Graphite. _______________________________________________ Mailing list: https://launchpad.net/~graphite-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~graphite-dev More help : https://help.launchpad.net/ListHelp
