tarantool / tarantool / 39416650057

88%

master: 88%

Build Type

push

github

Committed by sergepetrenko

Commit Message

box: skip NOPs in transaction iterators

A NOP statement changes no data but preserves its position in the WAL.
It can be produced e.g. by canceling a write in a before_replace trigger
or by skipping a duplicate-key conflict with replication_skip_conflict.

However, transaction iterators (like in `on_commit/rollback` e.g.) did
not handle NOPs properly. Iterating over one worked while a canceled
write still had its space (like in local NOPification with
`before_replace`). But a NOP read from WAL or replication has no space,
so accessing it through an iterator crashed. Dispatching triggers for
several spaces could crash for the same reason, even if their callbacks
never used the iterator.

Let's skip NOPs completely in transaction iterators. This changes
behavior for the NOPs during local NOPification, as triggers did see the
NOP row before the patch as `N, nil, nil, K` and now they won't. The
compat is not introduced, since it's doubtful anyone relied on NOPs to
be visible, since in almost all cases it just caused crash.

Closes #13163

NO_DOC=bugfix

(cherry picked from commit a1a0e05a1)

Coverage Stats

71416 of 119900 branches covered (59.56%)

8 of 8 new or added lines in 2 files covered. (100.0%)

74 existing lines in 14 files now uncovered.

106966 of 121875 relevant lines covered (87.77%)

1381025.89 hits per line