Error when database file exceeds 2GiB

[kspangsege]

Occasional error when the database file grows to beyond 2Gib.

The error has been seen when adding small lumps of data through many write transactions (1000-5000).

For unknown reasons, the database file often grows to these extreme sizes even with relatively little data inserted, but many transactions. In some cases, though, this does not happen, and the database file stays well below 100KiB for the exact same sequence and same number of inserts. This hints at another unrelated error.

The error almost always occurs at the 2GiB limit, but sometimes later. 3.1GiB has been observed.

The actual error varies, but this one is common:

group_writer.cpp:169: void tightdb::GroupWriter::WriteAt(std::size_t, const char*, std::size_t): Assertion `copy_end <= mmap_end' failed.