From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?utf-8?B?0JPQtdC+0YDQs9C40Lkg0JrQuNGA0LjRh9C10L3QutC+?= Subject: Re: [tarantool-patches] [PATCH v2 1/5] Do not promote wal vclock for failed writes Date: Tue, 29 Jan 2019 13:22:21 +0300 Message-ID: <2238035.WnxgNYYFuH@home.lan> In-Reply-To: <20190128112018.a7rwhjtfscqj5x6m@esperanza> References: <20190128112018.a7rwhjtfscqj5x6m@esperanza> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart3125956.CCJyVkbhoJ"; micalg="pgp-sha256"; protocol="application/pgp-signature" To: Vladimir Davydov Cc: tarantool-patches@freelists.org List-ID: --nextPart3125956.CCJyVkbhoJ Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Monday, January 28, 2019 2:20:18 PM MSK Vladimir Davydov wrote: > On Tue, Jan 22, 2019 at 01:31:09PM +0300, Georgy Kirichenko wrote: > > Increase replica lsn only if row was successfully written to disk. This > > prevents wal from lsn gaps in case of IO errors and enforces wal > > consistency. > > > > Needs for #980 > > --- > > > > src/box/wal.c | 19 ++++++--- > > test/xlog/errinj.result | 1 - > > test/xlog/panic_on_lsn_gap.result | 65 +++++++++++++++---------------- > > 3 files changed, 45 insertions(+), 40 deletions(-) > > > > diff --git a/src/box/wal.c b/src/box/wal.c > > index 3b50d3629..a55b544aa 100644 > > --- a/src/box/wal.c > > +++ b/src/box/wal.c > > @@ -901,16 +901,16 @@ wal_writer_begin_rollback(struct wal_writer *writer) > > > > } > > > > static void > > > > -wal_assign_lsn(struct wal_writer *writer, struct xrow_header **row, > > +wal_assign_lsn(struct vclock *vclock, struct xrow_header **row, > > > > struct xrow_header **end) > > > > { > > > > /** Assign LSN to all local rows. */ > > for ( ; row < end; row++) { > > > > if ((*row)->replica_id == 0) { > > > > - (*row)->lsn = vclock_inc(&writer->vclock, instance_id); > > + (*row)->lsn = vclock_inc(vclock, instance_id); > > > > (*row)->replica_id = instance_id; > > > > } else { > > > > - vclock_follow_xrow(&writer->vclock, *row); > > + vclock_follow_xrow(vclock, *row); > > > > } > > > > } > > > > } > > > > @@ -922,6 +922,11 @@ wal_write_to_disk(struct cmsg *msg) > > > > struct wal_msg *wal_msg = (struct wal_msg *) msg; > > struct error *error; > > > > + /* Local vclock copy. */ > > + struct vclock vclock; > > + vclock_create(&vclock); > > + vclock_copy(&vclock, &writer->vclock); > > + > > > > struct errinj *inj = errinj(ERRINJ_WAL_DELAY, ERRINJ_BOOL); > > while (inj != NULL && inj->bparam) > > > > usleep(10); > > > > @@ -974,14 +979,15 @@ wal_write_to_disk(struct cmsg *msg) > > > > struct journal_entry *entry; > > struct stailq_entry *last_committed = NULL; > > stailq_foreach_entry(entry, &wal_msg->commit, fifo) { > > > > - wal_assign_lsn(writer, entry->rows, entry->rows + entry- >n_rows); > > - entry->res = vclock_sum(&writer->vclock); > > + wal_assign_lsn(&vclock, entry->rows, entry->rows + entry- >n_rows); > > + entry->res = vclock_sum(&vclock); > > > > rc = xlog_write_entry(l, entry); > > if (rc < 0) > > > > goto done; > > > > if (rc > 0) { > > > > writer->checkpoint_wal_size += rc; > > last_committed = &entry->fifo; > > > > + vclock_copy(&writer->vclock, &vclock); > > I don't like that you copy a vclock after applying each entry. > Currently, it should be pretty cheap, but in future, when we make > vclock store any number of ids, this might get pretty heavy. > Can we minimize the number of memcpys somehow, ideally do it only > on the rollback path? In that case we should preserve vclock for rollback but it can be done only with vclock_copy to. vclock_copy is used only for whole batch with all entries. When we introduce unlimited vclock we should introduce vclock_diff also and then use them. > > > } > > /* rc == 0: the write is buffered in xlog_tx */ > > > > } > > > > @@ -991,6 +997,7 @@ wal_write_to_disk(struct cmsg *msg) > > > > writer->checkpoint_wal_size += rc; > > last_committed = stailq_last(&wal_msg->commit); > > > > + vclock_copy(&writer->vclock, &vclock); > > > > /* > > > > * Notify TX if the checkpoint threshold has been exceeded. > > > > @@ -1185,7 +1192,7 @@ wal_write_in_wal_mode_none(struct journal *journal, > > > > struct journal_entry *entry) > > > > { > > > > struct wal_writer *writer = (struct wal_writer *) journal; > > > > - wal_assign_lsn(writer, entry->rows, entry->rows + entry->n_rows); > > + wal_assign_lsn(&writer->vclock, entry->rows, entry->rows + > > entry->n_rows);> > > int64_t old_lsn = vclock_get(&replicaset.vclock, instance_id); > > int64_t new_lsn = vclock_get(&writer->vclock, instance_id); > > if (new_lsn > old_lsn) { > > > > diff --git a/test/xlog/errinj.result b/test/xlog/errinj.result > > index 390404b47..7f15bef35 100644 > > --- a/test/xlog/errinj.result > > +++ b/test/xlog/errinj.result > > @@ -43,7 +43,6 @@ require('fio').glob(name .. "/*.xlog") > > > > --- > > - - xlog/00000000000000000000.xlog > > > > - xlog/00000000000000000001.xlog > > > > - - xlog/00000000000000000002.xlog > > > > ... > > test_run:cmd('restart server default with cleanup=1') > > -- gh-881 iproto request with wal IO error > > > > diff --git a/test/xlog/panic_on_lsn_gap.result > > b/test/xlog/panic_on_lsn_gap.result index 4dd1291f8..8054baab4 100644 > > --- a/test/xlog/panic_on_lsn_gap.result > > +++ b/test/xlog/panic_on_lsn_gap.result > > @@ -105,7 +105,7 @@ test_run:cmd("restart server panic") > > > > -- > > box.info.vclock > > --- > > > > -- {1: 11} > > +- {1: 1} > > After this patch the comments contradict the expected result of this > test. Please fix. --nextPart3125956.CCJyVkbhoJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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