As we are ordering blocks we should specify ORDER BY clause when fetching them.

As of now, there is no ORDER BY clause and this may lead to unexpected results under certain conditions. The database engine gives no guarantee that the records will be fetched ascendingly by the primary key.

Sources:

• https://www.percona.com/doc/percona-server/8.0/flexibility/improved_memory_engine.html#caveats
• https://docs.microsoft.com/en-us/archive/blogs/craigfr/more-on-top

Steps to reproduce:
There aren't any.

Testing:
Switching the order of blocks and then saving should be tested.