[tarantool-patches] [PATCH v2 4/5] Emit NOP if an applier skips row
Vladimir Davydov
vdavydov.dev at gmail.com
Mon Jan 28 15:15:40 MSK 2019
On Tue, Jan 22, 2019 at 01:31:12PM +0300, Georgy Kirichenko wrote:
> Fill lsn gaps with NOP rows if applier configured to skip conflicting
> rows. This enforces wal consistency.
The patch may be worthwhile, but the comment sounds very obscure.
What's "wal consistency"? How can the wal become inconsistent without
this patch? Shouldn't there be a test proving this patch is correct?
>
> Prerequisite #980
> ---
> src/box/applier.cc | 29 ++++++++++++++++-------------
> 1 file changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/src/box/applier.cc b/src/box/applier.cc
> index 148c8ce5a..adbe88679 100644
> --- a/src/box/applier.cc
> +++ b/src/box/applier.cc
> @@ -533,23 +533,26 @@ applier_subscribe(struct applier *applier)
> row.replica_id);
> vclock_follow_xrow(&replicaset.applier.vclock, &row);
> int res = xstream_write(applier->subscribe_stream, &row);
> - if (res != 0) {
> - struct error *e = diag_last_error(diag_get());
> + struct error *e = diag_last_error(diag_get());
> + if (res != 0 && e->type == &type_ClientError &&
> + box_error_code(e) == ER_TUPLE_FOUND &&
> + replication_skip_conflict) {
> /**
> * Silently skip ER_TUPLE_FOUND error if such
> * option is set in config.
> */
> - if (e->type == &type_ClientError &&
> - box_error_code(e) == ER_TUPLE_FOUND &&
> - replication_skip_conflict)
> - diag_clear(diag_get());
> - else {
> - /* Rollback lsn to have a chance for a retry. */
> - vclock_set(&replicaset.applier.vclock,
> - row.replica_id, old_lsn);
> - latch_unlock(latch);
> - diag_raise();
> - }
> + diag_clear(diag_get());
> + row.type = IPROTO_NOP;
> + row.bodycnt = 0;
> + res = xstream_write(applier->subscribe_stream,
> + &row);
A comment explaining why this is done would be nice to have.
> + }
> + if (res != 0) {
> + /* Rollback lsn to have a chance for a retry. */
> + vclock_set(&replicaset.applier.vclock,
> + row.replica_id, old_lsn);
> + latch_unlock(latch);
> + diag_raise();
> }
> }
> done:
More information about the Tarantool-patches
mailing list