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I have some data stored in Azure blob storage, as gzip'd CSV files.
I'm then pulling the data into Power BI desktop and using a function with Binary.Decompress to decompress the files.
When I refresh the data, it shows as downloading way more than is actually on the storage - a blob container which should have around 5-600mb of files results in a reported download of well over 1gb. The queries are as follows:
Unzip Function:
(gZipFile) => let #"Unzip" = Binary.Decompress(gZipFile, Compression.GZip), #"CSV" = Csv.Document(#"Unzip"), #"Headers" = Table.PromoteHeaders(#"CSV", [PromoteAllScalars=true]) in #"Headers"
Blob Retrieval:
let Source = AzureStorage.Blobs("apdigitalproducts"), #"blobcontainer" = Source{[Name="googleanalyticsdata"]}[Data], #"Removed Other Columns" = Table.SelectColumns(#"blobcontainer",{"Content", "Name"}), #"Invoked Custom Function" = Table.AddColumn(#"Removed Other Columns", "Data", each fnDecompress([Content])), #"Removed Columns1" = Table.RemoveColumns(#"Invoked Custom Function",{"Content"}), #"Expanded Data" = Table.ExpandTableColumn(#"Removed Columns1", "Data", {"ga:visitorType", "ga:sourceMedium", "ga:country", "ga:landingPagePath", "ga:date", "ga:deviceCategory", "ga:fullReferrer", "ga:newUsers", "ga:sessions", "ga:pageviews", "ga:avgSessionDuration", "ga:avgTimeOnpage", "ga:users", "ga:pageviewsPerSession", "ga:sessionDuration", "ga:timeOnPage"}, {"ga:visitorType", "ga:sourceMedium", "ga:country", "ga:landingPagePath", "ga:date", "ga:deviceCategory", "ga:fullReferrer", "ga:newUsers", "ga:sessions", "ga:pageviews", "ga:avgSessionDuration", "ga:avgTimeOnpage", "ga:users", "ga:pageviewsPerSession", "ga:sessionDuration", "ga:timeOnPage"}) in #"Expanded Data"
Any ideas? Are the blobs being decompressed at the server side or something? I cannot work out at all what is going on here.
@dpws88 Random thought. In the Desktop there are auto generated tables for date hierarchies that are automatically created for every date column you have. Chris Webb did a blog about this and describes the behaviour and how to disable it in the options.
It might be the issue.
@dpws88 Same answer as this post, try it out and let one of them know. It is appreciated if you don't double post the same thing.