--- In firebird-support@yahoogroups.com, Walter Neumann <walter@b...>
wrote:

> TransIsolation: ReadCommitted.
> If user b change a row and commit it, then can user a see the

changed row.

Walter, if user A fetched row after user's B commit - yes.

> After them user a change the row and when he commit, he get the

error, that

> another user has changed the row.

Seems your description is'nt correct - DML statements indicates lock
conflict on execution, not on commit.

> Why?

Check user's A transaction is read_commited. Seems it is concurrency
or user B still did'nt commited changes.

> If user a read the row befor

user b

> has changed the row, then, of corse, he can not change.

In read_commited he can, if user B already commited changes,
regardless of read he row or not. In concurrency he can't if user B
changed row after user A started transaction regardless of are changes
made by user B commited or not.

> But after
> user b has
> committed, it schould be possible.

Yes.

> Any idea?

User A use concurrency or user B still did'nt commited.

Best regards, Alexander.