Forum Discussion
Data overflow error when the "List.Accumulate" function was used to process data over 2000 rows
Curt Hagenlocher's argument seems interesting to me.
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But broadly speaking, M is a lazy language and some of the things you compute actually result in promises instead of immediate values. If the combination function passed to List.Accumulate results in a promise, then the result of accumulating over your list is a promise on top of a promise on top of... etc. At some point, when the actual value is calculated, it's done recursively -- the chain of promises is too long and the stack flows over.
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Curt Hagenlocher's argument seems interesting to me.
<<...
But broadly speaking, M is a lazy language and some of the things you compute actually result in promises instead of immediate values. If the combination function passed to List.Accumulate results in a promise, then the result of accumulating over your list is a promise on top of a promise on top of... etc. At some point, when the actual value is calculated, it's done recursively -- the chain of promises is too long and the stack flows over.
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This forum thread is Google's top search result for "power query list.accumulate stack overflow". Unfortunately the Curt Hagenlocher's argument has been deleted - the link to the referenced post is broken, can't find the data.