[tarantool-patches] [PATCH v2 2/3] Put all new rows to the end of journal request
Vladimir Davydov
vdavydov.dev at gmail.com
Thu Mar 7 12:46:59 MSK 2019
On Wed, Mar 06, 2019 at 11:16:17PM +0300, Georgy Kirichenko wrote:
> Form a separate transaction with all local changes in case of replication.
> This is important because we should be able to replicate such changes
> (e.g. made within an on_replace triggers) back. In the opposite case
> local changes will be incorporated into originating transaction and
> wold be skipped by originator replica.
>
> Needed for: #2798
> ---
> src/box/txn.c | 36 ++++++++++++++++++++++++++++--------
> src/box/txn.h | 4 ++++
> 2 files changed, 32 insertions(+), 8 deletions(-)
>
> diff --git a/src/box/txn.c b/src/box/txn.c
> index 7900fb3ab..187e1c085 100644
> --- a/src/box/txn.c
> +++ b/src/box/txn.c
> @@ -141,6 +141,8 @@ txn_begin(bool is_autocommit)
> /* Initialize members explicitly to save time on memset() */
> stailq_create(&txn->stmts);
> txn->n_rows = 0;
> + txn->has_rows_with_lsn = false;
> + txn->has_rows_without_lsn = false;
> txn->is_autocommit = is_autocommit;
> txn->has_triggers = false;
> txn->is_aborted = false;
> @@ -233,6 +235,8 @@ txn_commit_stmt(struct txn *txn, struct request *request)
> if (stmt->space == NULL || !space_is_temporary(stmt->space)) {
> if (txn_add_redo(stmt, request) != 0)
> goto fail;
> + txn->has_rows_with_lsn |= stmt->row->replica_id != 0;
> + txn->has_rows_without_lsn |= stmt->row->replica_id == 0;
> ++txn->n_rows;
> }
> /*
> @@ -272,13 +276,29 @@ txn_write_to_wal(struct txn *txn)
>
> struct txn_stmt *stmt;
> struct xrow_header **row = req->rows;
> - stailq_foreach_entry(stmt, &txn->stmts, next) {
> - if (stmt->row == NULL)
> - continue; /* A read (e.g. select) request */
> - *row++ = stmt->row;
> - req->approx_len += xrow_approx_len(stmt->row);
> + if (txn->has_rows_with_lsn) {
> + /* Write out rows that already have an assigned lsn. */
> + stailq_foreach_entry(stmt, &txn->stmts, next) {
> + if (stmt->row == NULL)
> + continue; /* A read (e.g. select) request */
> + if (stmt->row->replica_id == 0)
> + continue; /* A row without lsn. */
> + *row++ = stmt->row;
> + req->approx_len += xrow_approx_len(stmt->row);
> + }
> + }
> + if (txn->has_rows_without_lsn) {
> + /* Write out rows to assign a lsn. */
> + stailq_foreach_entry(stmt, &txn->stmts, next) {
> + if (stmt->row == NULL)
> + continue; /* A read (e.g. select) request */
> + if (stmt->row->replica_id != 0)
> + continue; /* A row with lsn. */
> + *row++ = stmt->row;
> + req->approx_len += xrow_approx_len(stmt->row);
> + }
I liked the previous approach, where you counted remote rows, much more.
For one thing, it didn't require two passes over the statement list.
I don't understand why you ditched it.
> }
> - assert(row == req->rows + req->n_rows);
> + assert(row == req->rows + txn->n_rows);
>
> ev_tstamp start = ev_monotonic_now(loop());
> int64_t res = journal_write(req);
> @@ -399,8 +419,6 @@ txn_rollback()
> txn_stmt_unref_tuples(stmt);
>
> TRASH(txn);
> - /** Free volatile txn memory. */
> - fiber_gc();
> fiber_set_txn(fiber(), NULL);
> }
>
> @@ -480,6 +498,8 @@ box_txn_rollback()
> return -1;
> }
> txn_rollback(); /* doesn't throw */
> + /** Free volatile txn memory. */
> + fiber_gc();
> return 0;
> }
As I told you during the previous review session, moving fiber_gc from
txn_rollback to box_txn_rollback is a separate change. In fact, it's a
follow-up for 77fa1736dbb9 ("box: factor fiber_gc out of txn_commit").
Please submit it in a separate patch with a proper commentary.
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