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.
* 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
It is possible to have a VARCHAR column that isn't NUL terminated, an
example of this is a union of two CHAR columns. So the length should
always act as a terminator when there is no NUL.
