Instead of a seperate param for cache size, we decided
to allow an override of the NumBlocksPct param instead.
If NumBlocksPct ends in an 'm' or a 'g', it will be interpreted
as megabytes or gigabytes instead of a %age.
This adds options which are user enabled to debug the LRU cache inside
ColumnStore. Specifically cache flushing.
It adds the following:
* PrimProc flush information when SIGUSR2 mode is enabled
* cpimport dictionary flush information when -d2 is used
* WriteEngineServer DML flush information to STDERR
The FIFO buffer could get data in next() whilst a data swap is happening
due to a rare race condition. This patch adds mutexes around the parts
that could race.
The observed effect of this race was during a complex aggregate query
the results would occasionally be incorrect.
In addition this fixes a race condition in PrimProc's regex processor.
PriorityThreadPool didn't have very good error handling. If something
failed it would just ignore whatever was being processed. This could
lead to a query continuing without retreiving all of the required data.
This patch adds error handling, sending a message back to the client
and a log message. It also destroys and recreates the pool thread.
SQL-92 basically specifies for a NOPAD collation that only space should
be ignored for matches. Tabs and other whitespace are handled
differently. We don't fully support collations yet so we assume the
defaults.
For TEXT columns (and some other scenarios) we don't do a DSS step to
scan dictionaries and do it directly in the BPS step instead. This patch
applies the previous fix to this case too.
For equality string matches other engines ignore trailing whitespace
(this does not apply to LIKE matches). So we should do the same. This
patch trims whitespace for MIN/MAX extent elimination checks, fixed
width columns and dictionary columns during equality matches against
constants (SELECT * FROM t1 WHERE b = 'ABC').
