* Introduce multigeneration aggregation
* Do not save unused part of RGDatas to disk
* Add IO error explanation (strerror)
* Reduce memory usage while aggregating
* introduce in-memory generations to better memory utilization
* Try to limit the qty of buckets at a low limit
* Refactor disk aggregation a bit
* pass calculated hash into RowAggregation
* try to keep some RGData with free space in memory
* do not dump more than half of rowgroups to disk if generations are
allowed, instead start a new generation
* for each thread shift the first processed bucket at each iteration,
so the generations start more evenly
* Unify temp data location
* Explicitly create temp subdirectories
whether disk aggregation/join are enabled or not
ColumnStore now uses standard bin/lib paths for pretty much everything.
Data path is now hard-coded to /var/lib/columnstore.
This patch also:
* Removes v1 decompression
* Removes a bunch of unneeded files
* Removes COLUMNSTORE_INSTALL_DIR / $INSTALLDIR
* Makes my.cnf.d work for all platforms (MCOL-3558)
* Changes configcpp to use recursive mutex (fixes possible config write deadlock)
* Fixes MCOL-3599 Fix regr functions, The library was installed in the wrong location
* Fixes a bunch of Ubuntu packaging issues
* Changes the binary names of several of the executables so as not to
clash with potential executables from other packages
