StringStore originally worked by returning a 32bit pointer to a memory
location and storing the length with that pointer. This allowed 4GB to
be stored in 64KB blocks. With 1.1 we used the high bit to signify a
TEXT/BLOB string of > 64KB reducing the max capacity to 2GB but without
any bounds checking.
So, if you went over the 2GB mark the getter would think you are trying
to get a long string instead of a short one and come up empty. It would
then return NULL.
This patch uses 64bit memory points still retaining the high bit to
signify long strings. It also now stores the length with the string
rather than with the pointer to allow the full 64bits for pointers.
It also adds a bounds check for small strings.
We should have been initalizing TEXT/BLOB 8 byte tokens for NULL,
instead we were initializing the entire length of the TEXT/BLOB which
can do a lot of damage.
StringStore as a vector of std::string had a performance regressions and
a rare crash.
This new version of StringStore restores the original StringStore with
the 64KB limitation and adds another vector to store strings that won't
fit into the small string storage.
The fix for MCOL-838 broke VARBINARY as it truncated on the first NUL on
StringStore deserialize. This fix uses append() to force a copy instead
whilst preserving length.
This fixes test012
* TEXT and BLOB now have separate identifiers internally
* TEXT columns are identified as such in system catalog
* cpimport only requires hex input for BLOB, not TEXT
This patch adds enough support so that cross engines joins with blob
columns in the foreign engines will work. The modifications are as
follows:
* Add CrossEngine support for non-NULL-terminated (binary) data
* Add row data support for blobs (similar to varbinary)
* Add engine support for writing out blob data correctly to the storage
engine API
* Re-enable blob support in the engine plugin
This fix improves the performance of ExeMgr by doing the following:
* Significantly reduces the amount of time the xml configuration is
scanned
* Uses a much faster way to determine the CPU core count
* Reduces the amount of times certain allocations are executed
* Rowgroup pre-allocates vectors for 1024 rows
This improves performance for the first query of a connection and the
performance for smaller result sets. It may well improve performance in
other areas too.
