[PATCH 1/4] vinyl: introduce hash of spaces affected by transaction
Vladimir Davydov
vdavydov.dev at gmail.com
Sun Mar 24 00:07:21 MSK 2019
We need to abort all transactions writing to an altered space when
a new index is build. Currently, we use the write set to look up such
transactions, but it isn't quite correct, because a transaction could
yield on disk read before inserting a statement into the write set.
To address this problem, this patch introduces a hash of spaces affected
by each transaction and makes tx_manager_abort_writers_for_ddl() use it
instead of the write set to abort transactions for DDL.
Needed for #3420
---
src/box/vinyl.c | 12 ++++++------
src/box/vy_tx.c | 26 ++++++++++++++++++++++----
src/box/vy_tx.h | 44 +++++++++++++++++++++++++++++++++++++++++---
3 files changed, 69 insertions(+), 13 deletions(-)
diff --git a/src/box/vinyl.c b/src/box/vinyl.c
index 3ef43e18..a6a5f187 100644
--- a/src/box/vinyl.c
+++ b/src/box/vinyl.c
@@ -1034,14 +1034,14 @@ vinyl_space_prepare_alter(struct space *old_space, struct space *new_space)
/**
* This function is called after installing on_replace trigger
* used for propagating changes done during DDL. It aborts all
- * rw transactions affecting the given LSM tree that began
+ * rw transactions affecting the given space that began
* before the trigger was installed so that DDL doesn't miss
* their working set.
*/
static void
-vy_abort_writers_for_ddl(struct vy_env *env, struct vy_lsm *lsm)
+vy_abort_writers_for_ddl(struct vy_env *env, struct space *space)
{
- tx_manager_abort_writers_for_ddl(env->xm, lsm);
+ tx_manager_abort_writers_for_ddl(env->xm, space);
/*
* Wait for prepared transactions to complete
* (we can't abort them as they reached WAL).
@@ -1115,7 +1115,7 @@ vinyl_space_check_format(struct space *space, struct tuple_format *format)
trigger_create(&on_replace, vy_check_format_on_replace, &ctx, NULL);
trigger_add(&space->on_replace, &on_replace);
- vy_abort_writers_for_ddl(env, pk);
+ vy_abort_writers_for_ddl(env, space);
struct vy_read_iterator itr;
vy_read_iterator_open(&itr, pk, NULL, ITER_ALL, pk->env->empty_key,
@@ -2434,7 +2434,7 @@ vinyl_engine_begin_statement(struct engine *engine, struct txn *txn)
struct vy_tx *tx = txn->engine_tx;
struct txn_stmt *stmt = txn_current_stmt(txn);
assert(tx != NULL);
- return vy_tx_begin_statement(tx, &stmt->engine_savepoint);
+ return vy_tx_begin_statement(tx, stmt->space, &stmt->engine_savepoint);
}
static void
@@ -4229,7 +4229,7 @@ vinyl_space_build_index(struct space *src_space, struct index *new_index,
trigger_create(&on_replace, vy_build_on_replace, &ctx, NULL);
trigger_add(&src_space->on_replace, &on_replace);
- vy_abort_writers_for_ddl(env, pk);
+ vy_abort_writers_for_ddl(env, src_space);
struct vy_read_iterator itr;
vy_read_iterator_open(&itr, pk, NULL, ITER_ALL, pk->env->empty_key,
diff --git a/src/box/vy_tx.c b/src/box/vy_tx.c
index ae660dd8..56d594e5 100644
--- a/src/box/vy_tx.c
+++ b/src/box/vy_tx.c
@@ -311,6 +311,7 @@ vy_tx_create(struct tx_manager *xm, struct vy_tx *tx)
tx->is_applier_session = false;
tx->read_view = (struct vy_read_view *)xm->p_global_read_view;
vy_tx_read_set_new(&tx->read_set);
+ vy_tx_space_hash_new(&tx->space_hash);
tx->psn = 0;
rlist_create(&tx->on_destroy);
rlist_create(&tx->in_writers);
@@ -849,13 +850,31 @@ vy_tx_rollback(struct vy_tx *tx)
}
int
-vy_tx_begin_statement(struct vy_tx *tx, void **savepoint)
+vy_tx_begin_statement(struct vy_tx *tx, struct space *space, void **savepoint)
{
if (tx->state == VINYL_TX_ABORT) {
diag_set(ClientError, ER_TRANSACTION_CONFLICT);
return -1;
}
assert(tx->state == VINYL_TX_READY);
+
+ struct vy_tx_space_hash_entry *space_entry;
+ space_entry = vy_tx_space_hash_search(&tx->space_hash, space);
+ if (space_entry == NULL) {
+ /*
+ * Allocate a slot for the modified space in the hash.
+ * It will be freed automatically along with the region
+ * when the transaction is committed or rolled back.
+ */
+ space_entry = region_alloc(&fiber()->gc, sizeof(*space_entry));
+ if (space_entry == NULL) {
+ diag_set(OutOfMemory, sizeof(*space_entry),
+ "region", "space hash entry");
+ return -1;
+ }
+ space_entry->space = space;
+ vy_tx_space_hash_insert(&tx->space_hash, space_entry);
+ }
if (stailq_empty(&tx->log))
rlist_add_entry(&tx->xm->writers, tx, in_writers);
*savepoint = stailq_last(&tx->log);
@@ -1086,13 +1105,12 @@ vy_tx_set_with_colmask(struct vy_tx *tx, struct vy_lsm *lsm,
}
void
-tx_manager_abort_writers_for_ddl(struct tx_manager *xm, struct vy_lsm *lsm)
+tx_manager_abort_writers_for_ddl(struct tx_manager *xm, struct space *space)
{
struct vy_tx *tx;
rlist_foreach_entry(tx, &xm->writers, in_writers) {
if (tx->state == VINYL_TX_READY &&
- write_set_search_key(&tx->write_set, lsm,
- lsm->env->empty_key) != NULL)
+ vy_tx_space_hash_search(&tx->space_hash, space) != NULL)
vy_tx_abort(tx);
}
}
diff --git a/src/box/vy_tx.h b/src/box/vy_tx.h
index aaa31bee..fada41f1 100644
--- a/src/box/vy_tx.h
+++ b/src/box/vy_tx.h
@@ -51,6 +51,7 @@
extern "C" {
#endif /* defined(__cplusplus) */
+struct space;
struct tuple;
struct tx_manager;
struct vy_mem;
@@ -133,6 +134,38 @@ write_set_search_key(write_set_t *tree, struct vy_lsm *lsm,
return write_set_search(tree, &key);
}
+/**
+ * Represents a space affected by a transaction.
+ * See vy_tx::space_hash.
+ */
+struct vy_tx_space_hash_entry {
+ struct space *space;
+ rb_node(struct vy_tx_space_hash_entry) in_hash;
+};
+
+static inline int
+vy_tx_space_hash_cmp(struct vy_tx_space_hash_entry *a,
+ struct vy_tx_space_hash_entry *b)
+{
+ if (a->space != b->space)
+ return a->space < b->space ? -1 : 1;
+ return 0;
+}
+
+static inline int
+vy_tx_space_hash_key_cmp(struct space *space,
+ struct vy_tx_space_hash_entry *entry)
+{
+ if (space != entry->space)
+ return space < entry->space ? -1 : 1;
+ return 0;
+}
+
+typedef rb_tree(struct vy_tx_space_hash_entry) vy_tx_space_hash_t;
+rb_gen_ext_key(MAYBE_UNUSED static inline, vy_tx_space_hash_,
+ vy_tx_space_hash_t, struct vy_tx_space_hash_entry, in_hash,
+ vy_tx_space_hash_cmp, struct space *, vy_tx_space_hash_key_cmp);
+
/** Transaction object. */
struct vy_tx {
/** Link in tx_manager::writers. */
@@ -181,6 +214,11 @@ struct vy_tx {
*/
vy_tx_read_set_t read_set;
/**
+ * Spaces affected by this transaction.
+ * Used for aborting transactions on DDL.
+ */
+ vy_tx_space_hash_t space_hash;
+ /**
* Prepare sequence number or -1 if the transaction
* is not prepared.
*/
@@ -277,12 +315,12 @@ size_t
tx_manager_mem_used(struct tx_manager *xm);
/**
- * Abort all rw transactions that affect the given LSM tree
+ * Abort all rw transactions that affect the given space
* and haven't reached WAL yet. Called before executing a DDL
* operation.
*/
void
-tx_manager_abort_writers_for_ddl(struct tx_manager *xm, struct vy_lsm *lsm);
+tx_manager_abort_writers_for_ddl(struct tx_manager *xm, struct space *space);
/**
* Abort all local rw transactions that haven't reached WAL yet.
@@ -327,7 +365,7 @@ vy_tx_rollback(struct vy_tx *tx);
* to a save point with vy_tx_rollback_statement().
*/
int
-vy_tx_begin_statement(struct vy_tx *tx, void **savepoint);
+vy_tx_begin_statement(struct vy_tx *tx, struct space *space, void **savepoint);
/**
* Rollback a transaction statement.
--
2.11.0
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