From: Aleksandr Lyapunov <alyapunov@tarantool.org> To: tarantool-patches@dev.tarantool.org Subject: [Tarantool-patches] [PATCH v3 09/13] tmx: introduce prepare sequence number Date: Wed, 15 Jul 2020 16:55:32 +0300 [thread overview] Message-ID: <1594821336-14468-10-git-send-email-alyapunov@tarantool.org> (raw) In-Reply-To: <1594821336-14468-1-git-send-email-alyapunov@tarantool.org> Prepare sequence number is a monotonically increasing ID that is assigned to any prepared transaction. This ID is suitable for serialization order resolution: the bigger is ID - the latter the transaction exist in the serialization order of transactions. Note that id of transactions has quite different order in case when transaction could yield - an younger (bigger id) transaction can prepare/commit first (lower psn) while older tx sleeps in vain. Also it should be mentioned that LSN has the same order as PSN, but it has two general differences: 1. The LSN sequence has no holes, i.e. it is a natural number sequence. This property is useless for transaction engine. 2. The LSN sequence is provided by WAL writer and thus LSN is not available for TX thas was prepared and haven't been committed yet. That feature makes psn more suitable sequence for transactions as it allows to order prepared but not committed transaction and allows, for example, to create a read view between prepared transactions. Part of #4897 --- src/box/txn.c | 5 +++++ src/box/txn.h | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/src/box/txn.c b/src/box/txn.c index d647fc9..7a15986 100644 --- a/src/box/txn.c +++ b/src/box/txn.c @@ -40,6 +40,8 @@ struct tx_manager { + /** Last prepare-sequence-number that was assigned to prepared TX. */ + int64_t last_psn; }; /** That's a definition, see declaration for description. */ @@ -242,6 +244,7 @@ txn_begin(void) txn->flags = 0; txn->in_sub_stmt = 0; txn->id = ++tsn; + txn->psn = 0; txn->status = TXN_INPROGRESS; txn->signature = TXN_SIGNATURE_ROLLBACK; txn->engine = NULL; @@ -650,6 +653,8 @@ txn_journal_entry_new(struct txn *txn) static int txn_prepare(struct txn *txn) { + txn->psn = ++txm.last_psn; + if (txn_has_flag(txn, TXN_IS_ABORTED_BY_YIELD)) { assert(!txn_has_flag(txn, TXN_CAN_YIELD)); diag_set(ClientError, ER_TRANSACTION_YIELD); diff --git a/src/box/txn.h b/src/box/txn.h index a2374f3..b5b94fd 100644 --- a/src/box/txn.h +++ b/src/box/txn.h @@ -270,6 +270,11 @@ struct txn { * Valid IDs start from 1. */ int64_t id; + /** + * A sequential ID that is assigned when the TX become prepared. + * Transactions are committed in that order. + */ + int64_t psn; /** Status of the TX */ enum txn_status status; /** List of statements in a transaction. */ -- 2.7.4
next prev parent reply other threads:[~2020-07-15 13:55 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-15 13:55 [Tarantool-patches] [PATCH v3 00/13] Transaction engine for memtx engine Aleksandr Lyapunov 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 01/13] Update license file (2020) Aleksandr Lyapunov 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 02/13] Check data_offset overflow in struct tuple Aleksandr Lyapunov 2020-07-16 14:27 ` Nikita Pettik 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 03/13] vinyl: rename tx_manager -> vy_tx_manager Aleksandr Lyapunov 2020-07-15 16:04 ` Nikita Pettik 2020-07-16 8:17 ` Aleksandr Lyapunov 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 04/13] txm: introduce dirty tuples Aleksandr Lyapunov 2020-07-15 16:22 ` Nikita Pettik 2020-07-16 0:05 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 05/13] txm: save txn in txn_stmt Aleksandr Lyapunov 2020-07-15 16:23 ` Nikita Pettik 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 06/13] txm: add TX status Aleksandr Lyapunov 2020-07-15 16:42 ` Nikita Pettik 2020-07-16 0:08 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 07/13] txm: save does_require_old_tuple flag in txn_stmt Aleksandr Lyapunov 2020-07-15 16:49 ` Nikita Pettik 2020-07-16 0:09 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 08/13] txm: introduce tx manager Aleksandr Lyapunov 2020-07-15 16:51 ` Nikita Pettik 2020-07-15 22:01 ` Vladislav Shpilevoy 2020-07-16 0:10 ` Vladislav Shpilevoy 2020-07-15 13:55 ` Aleksandr Lyapunov [this message] 2020-07-15 17:13 ` [Tarantool-patches] [PATCH v3 09/13] tmx: introduce prepare sequence number Nikita Pettik 2020-07-16 0:11 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 10/13] tmx: introduce conflict tracker Aleksandr Lyapunov 2020-07-16 0:16 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 11/13] txm: introduce txm_story Aleksandr Lyapunov 2020-07-16 0:20 ` Vladislav Shpilevoy 2020-07-17 6:16 ` Aleksandr Lyapunov 2020-07-16 22:25 ` Vladislav Shpilevoy 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 12/13] txm: clarify all fetched tuples Aleksandr Lyapunov 2020-07-15 13:55 ` [Tarantool-patches] [PATCH v3 13/13] tmx: use new tx manager in memtx Aleksandr Lyapunov 2020-07-16 22:26 ` Vladislav Shpilevoy 2020-07-17 5:08 ` Aleksandr Lyapunov 2020-07-23 20:58 ` Vladislav Shpilevoy 2020-07-15 15:47 ` [Tarantool-patches] [PATCH v3 00/13] Transaction engine for memtx engine Aleksandr Lyapunov 2020-07-15 16:38 ` Aleksandr Lyapunov 2020-07-15 16:39 ` Aleksandr Lyapunov 2020-07-15 16:40 ` Aleksandr Lyapunov 2020-07-16 0:05 ` Vladislav Shpilevoy
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