I haven't looked at the code yet, just skimmed over the commit message,
but already have a couple of questions that I think should be clarified
in the documentation request.
On Thu, Aug 16, 2018 at 08:57:10PM +0300, Vladislav Shpilevoy wrote:
On commit/rollback triggers are already implemented
within Tarantool internals. The patch just exposes
them for Lua. Below the API is described, which
deserves an attention though.
Closes #857
@TarantoolBot document
Title: Document box.on_commit/on_rollback triggers
On commit/rollback triggers can be set similar to
space:on_replace triggers:
box.on_commit/rollback(new_trigger, old_trigger)
A trigger can be set only inside an active
transaction. When a trigger is called, it takes 1
parameter: an iterator over the transaction
statements.
box.on_commit(function(iterator)
for i, old_tuple, new_tuple, space_id in iterator() do
-- Do something with tuples and space ...
end
end)
On each step the iterator returns 4 values: statement
number (grows from 1 to statement count), old tuple or
nil, new tuple or nil and space id. Old tuple is not
nil when the statement updated or deleted the existing
tuple. New tuple is not nil when the statement updated
or inserted the tuple.
The iterator can not be used outside of the trigger.
Otherwise it throws an error.
On_commit/rollback triggers shall not fail, otherwise
Tarantool exits with panic.
