Related to #45081
StringIndexSort now properly handles collections with all-null string
fields by:
- Removing the error thrown when unique_count is 0 in ParseBinaryData
- Adding alignment and padding support in mmap serialization (similar to
ScalarIndexSort)
- Separating data_size_ from mmap_size_ to correctly parse data without
reading padding
This fixes load collection timeout failures when all string field data
is null, particularly affecting STL_SORT and TRIE index types.
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
fd0ef09e97