DBRM connections are reused so that we don't have a huge amount of
TIME_WAIT sockets when there are large amounts of DML. Also applied to
i_s.columnstore_files
The string stream which builds up the PM details wasn't cleared on each
run. This moves the creation of the string stream up to where it is
needed so a clean one is used each time.
I_S.COLUMNSTORE_FILES returned bad filenames and NULL file sizes when
there are multiple nodes in a ColumnStore cluster
It adds an extra message call to the WriteEngine to get the file size
for that file. The I_S function will figure out which WriteEngine to
communicate with and get the file size details from it.
* Add INFORMATION_SCHEMA.COLUMNSTORE_FILES which contains information
about files
* Remove file information from COLUMNSTORE_EXTENTS (due to above)
* Hide columns with Object ID < 3000 (internal columns)
* Fix bad calculation in data_size columns
* Fix minor memory leak
* Add compressedSize() function to IDBFileSystem to get the used file
size for a compressed file
* Add columnstore_info schema with utility stored procedures to access
the information_schema tables
