With an XLSX pivot table - it is possible to base the data source on a range name. That range name can contain a very large range that is full of empty cells =) for example SheetFoo!$A:$Z. Then as we fillTable on this we burn a huge amount of time iterating over ~1 million empty cells repeatedly looking up the same pointless (blank) information =) Sadly a private example file, but no doubt reasonably easy to construct one.
Created attachment 121397 [details] pivot range test. Takes ~30+ seconds to open for me, and ~25 seconds to refresh the (trivial) pivot =)
Michael Meeks committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=6833f382c5c8350256e97e2b342eb939a8c373ba tdf#96588 - avoid redundant work on large numbers of trailing rows. It will be available in 5.2.0. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Michael Meeks committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=cd945a000623838e96b7dd534ca618071c44995d tdf#96588 - avoid redundant pivot cache filter on import. It will be available in 5.2.0. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Testing Bug 90129, I encountered on this one. That one is not solved, and this one looks like it is. Although I couldn't notice a difference on the attached file, of course.
*** Bug 96589 has been marked as a duplicate of this bug. ***
I guess it should be closed.