[PATCH 06/10] ddl: restore sequence value if drop is rolled back
Vladimir Davydov
vdavydov.dev at gmail.com
Wed Jul 3 22:30:08 MSK 2019
A sequence isn't supposed to roll back to the old value if the
transaction it was used in is aborted for some reason. However,
if a sequence is dropped, we do want to restore the original
value on rollback so that we don't lose it on an unsuccessful
attempt to drop the sequence.
---
src/box/alter.cc | 24 ++++++++++++++++++++++++
test/box/sequence.result | 21 +++++++++++++++++++++
test/box/sequence.test.lua | 10 ++++++++++
3 files changed, 55 insertions(+)
diff --git a/src/box/alter.cc b/src/box/alter.cc
index 89ab9c65..4f046ef6 100644
--- a/src/box/alter.cc
+++ b/src/box/alter.cc
@@ -3460,6 +3460,20 @@ on_replace_dd_sequence(struct trigger * /* trigger */, void *event)
trigger_run_xc(&on_alter_sequence, seq);
}
+/** Restore the old sequence value on rollback. */
+static void
+on_drop_sequence_data_rollback(struct trigger *trigger, void * /* event */)
+{
+ struct tuple *tuple = (struct tuple *)trigger->data;
+ uint32_t id = tuple_field_u32_xc(tuple, BOX_SEQUENCE_DATA_FIELD_ID);
+ int64_t val = tuple_field_i64_xc(tuple, BOX_SEQUENCE_DATA_FIELD_VALUE);
+
+ struct sequence *seq = sequence_by_id(id);
+ assert(seq != NULL);
+ if (sequence_set(seq, val) != 0)
+ panic("Can't restore sequence value");
+}
+
/**
* A trigger invoked on replace in space _sequence_data.
* Used to update a sequence value.
@@ -3483,6 +3497,16 @@ on_replace_dd_sequence_data(struct trigger * /* trigger */, void *event)
if (sequence_set(seq, value) != 0)
diag_raise();
} else { /* DELETE */
+ /*
+ * A sequence isn't supposed to roll back to the old
+ * value if the transaction it was used in is aborted
+ * for some reason. However, if a sequence is dropped,
+ * we do want to restore the original sequence value
+ * on rollback.
+ */
+ struct trigger *on_rollback = txn_alter_trigger_new(
+ on_drop_sequence_data_rollback, old_tuple);
+ txn_on_rollback(txn, on_rollback);
sequence_reset(seq);
}
}
diff --git a/test/box/sequence.result b/test/box/sequence.result
index 99eed0ec..91795290 100644
--- a/test/box/sequence.result
+++ b/test/box/sequence.result
@@ -2249,3 +2249,24 @@ sq:drop()
s:drop()
---
...
+--
+-- Check that if a deletion from _sequence_data is rolled back,
+-- the sequence state is restored.
+--
+sq = box.schema.sequence.create('test')
+---
+...
+sq:next() -- 1
+---
+- 1
+...
+box.begin() box.space._sequence_data:delete{sq.id} box.rollback()
+---
+...
+sq:next() -- 2
+---
+- 2
+...
+sq:drop()
+---
+...
diff --git a/test/box/sequence.test.lua b/test/box/sequence.test.lua
index 9615c447..b0ec020e 100644
--- a/test/box/sequence.test.lua
+++ b/test/box/sequence.test.lua
@@ -761,3 +761,13 @@ s:insert{box.NULL} -- ok
s.index.pk:alter{sequence = false}
sq:drop()
s:drop()
+
+--
+-- Check that if a deletion from _sequence_data is rolled back,
+-- the sequence state is restored.
+--
+sq = box.schema.sequence.create('test')
+sq:next() -- 1
+box.begin() box.space._sequence_data:delete{sq.id} box.rollback()
+sq:next() -- 2
+sq:drop()
--
2.11.0
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