[tarantool-patches] [PATCH v3 08/14] wal: enable asyncronous wal writes
Vladimir Davydov
vdavydov.dev at gmail.com
Thu Jun 13 17:21:11 MSK 2019
On Sun, Jun 09, 2019 at 11:44:37PM +0300, Georgy Kirichenko wrote:
> Allow to send a journal entry to wal without to wait until the writing
> was finished. Two methods were introduced:
> * async_write method emits an entry to be written, returns 0 if the
> entry was successfully scheduled;
> * async_wait method waits until writing was finished and returns a
> result of journal write.
>
> Prerequisites: #1254
> ---
> src/box/box.cc | 30 ++++++++++++++++++++---
> src/box/journal.c | 21 +++++++++++++++-
> src/box/journal.h | 30 +++++++++++++++++++++++
> src/box/wal.c | 62 +++++++++++++++++++++++++++++++++++++++++------
> 4 files changed, 130 insertions(+), 13 deletions(-)
>
> diff --git a/src/box/box.cc b/src/box/box.cc
> index a88e762c0..d0616095b 100644
> --- a/src/box/box.cc
> +++ b/src/box/box.cc
> @@ -308,19 +308,41 @@ struct recovery_journal {
> * min/max LSN of created LSM levels.
> */
> static int64_t
> -recovery_journal_write(struct journal *base,
> - struct journal_entry *entry)
> +recovery_journal_async_write(struct journal *base,
> + struct journal_entry *entry)
And in one of the following patches you rename it back to
recovery_journal_write...
This series needs to be resplit.
> {
> struct recovery_journal *journal = (struct recovery_journal *) base;
> + entry->res = vclock_sum(journal->vclock);
> entry->done = true;
> fiber_cond_broadcast(&entry->done_cond);
> - return vclock_sum(journal->vclock);
> + return 0;
> +}
> +
> +static int64_t
> +recovery_journal_async_wait(struct journal *base,
> + struct journal_entry *entry)
> +{
> + (void) base;
> + assert(entry->done);
> + return entry->res;
> +}
> +
> +static int64_t
> +recovery_journal_write(struct journal *base,
> + struct journal_entry *entry)
> +{
> + if (recovery_journal_async_write(base, entry) == 0)
> + return recovery_journal_async_wait(base, entry);
> + return -1;
The 'journal_write' callback looks exactly the same for all
implementations hence we could move this code up to the generic
level.
Anyway, as I said I have concerns re the wakeup design - see my comments
to the final patch.
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