In DateTimeUtils.getTimeTry(), Calendar instances used to evaluate Timestamps were only being cached if no timezone was specified. I've added code to reuse Calendar instances if the timezone specified matches the previous use.

Multi-threaded processing: concurrent deleting the same row could throw the exception Row not found when trying to delete

MVStore transactions: a thread could see a change of a different thread within a different map. Pull request #153.

MVStore transactions: a thread could see a change of a different thread within a different map. Pull request #153.

Test case for undoLog synchronization race and proposed fix

COLUMNS metatable

Table engine improvements

For compatibility with other databases, support for (double and float) -0.0 has been removed. 0.0 is used instead.

In version 1.4.186, order by was broken in some cases due to the change Make the planner use indexes for sorting when doing a GROUP BY. The change was reverted.

about which tables each thread has locked