Tarantool development patches archive
 help / color / mirror / Atom feed
From: Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: tarantool-patches@dev.tarantool.org
Subject: Re: [Tarantool-patches] [PATCH 04/13] wal: refactor wal_write_to_disk()
Date: Thu, 17 Jun 2021 01:32:52 +0200
Message-ID: <c3ea0f6b-02d8-4bcc-e578-1af7bda0cda3@tarantool.org> (raw)
In-Reply-To: <YMmwA//5TKFulb2Z@grain>

Hi! Thanks for the review!

>>>> @@ -1038,7 +1036,10 @@ wal_write_to_disk(struct cmsg *msg)
>>>>  {
>>>>  	struct wal_writer *writer = &wal_writer_singleton;
>>>>  	struct wal_msg *wal_msg = (struct wal_msg *) msg;
>>>>  	struct error *error;
>>>> +	assert(!stailq_empty(&wal_msg->commit));
>>>
>>> Hi Vlad, you know I don't understand why we need this assert...
>>
>> Otherwise in case of, for instance, rotate fail, the rollback won't
>> start.
> 
> But the current whole code logic is assuming that if commit chain
> is empty then there was no data to write or rollback, iow codeflow
> is using list emptiness as a sign of data to procceed. If we really
> want to prohibit calling wal_write_to_disk with no entries then
> maybe better put panic here?
> 
> The wal_msg->commit entry is accessed later in code anyway via bpu,
> which means that if we add
> 
> 	if (stailq_empty(&wal_msg->commit))
> 		panic("wal: attempt to update vclock without data");
> 
> this won't cause perf degradation since after a few lines you gonna be
> testing @commit again where bpu entry is already filled and this will
> allow us to catch problems on release builds as well.
> 
> Don't get me wrong please I simply don't like assert() with a passion
> because it hides problems which might happen on release builds.
> 
> Anyway, just a proposal, if you still prefer calling assert here, ok
> let it be.

I added the panic:

====================
diff --git a/src/box/wal.c b/src/box/wal.c
index 40382e791..cb8b2eac1 100644
--- a/src/box/wal.c
+++ b/src/box/wal.c
@@ -1039,7 +1039,8 @@ wal_write_to_disk(struct cmsg *msg)
 	struct stailq_entry *last_committed = NULL;
 	struct journal_entry *entry;
 	struct error *error;
-	assert(!stailq_empty(&wal_msg->commit));
+	if (stailq_empty(&wal_msg->commit))
+		panic("Attempted to write an empty batch to WAL");
 
 	/*
 	 * Track all vclock changes made by this batch into

  reply	other threads:[~2021-06-16 23:32 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-11 21:56 [Tarantool-patches] [PATCH 00/13] Applier rollback reason Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 01/13] error: introduce ER_CASCADE_ROLLBACK Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 10/13] txn: install proper diag errors on txn fail Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 11/13] wal: introduce JOURNAL_ENTRY_ERR_CASCADE Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 12/13] txn: introduce TXN_SIGNATURE_ABORT Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 13/13] txn: stop TXN_SIGNATURE_ABORT override Vladislav Shpilevoy via Tarantool-patches
2021-06-15 13:44   ` Serge Petrenko via Tarantool-patches
2021-06-15 19:34     ` Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 02/13] test: remove replica-applier-rollback.lua Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 03/13] journal: make journal_write() set diag on error Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 04/13] wal: refactor wal_write_to_disk() Vladislav Shpilevoy via Tarantool-patches
2021-06-15 20:46   ` Cyrill Gorcunov via Tarantool-patches
2021-06-16  6:22     ` Vladislav Shpilevoy via Tarantool-patches
2021-06-16  8:02       ` Cyrill Gorcunov via Tarantool-patches
2021-06-16 23:32         ` Vladislav Shpilevoy via Tarantool-patches [this message]
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 05/13] diag: introduce diag_set_detailed() Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 06/13] wal: encapsulate ER_WAL_IO Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 07/13] txn: change limbo rollback check in the trigger Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 08/13] journal: introduce proper error codes Vladislav Shpilevoy via Tarantool-patches
2021-06-11 21:56 ` [Tarantool-patches] [PATCH 09/13] txn: assert after WAL write that txn is not done Vladislav Shpilevoy via Tarantool-patches
2021-06-15 13:43 ` [Tarantool-patches] [PATCH 00/13] Applier rollback reason Serge Petrenko via Tarantool-patches
2021-06-16 23:32 ` Vladislav Shpilevoy via Tarantool-patches

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=c3ea0f6b-02d8-4bcc-e578-1af7bda0cda3@tarantool.org \
    --to=tarantool-patches@dev.tarantool.org \
    --cc=gorcunov@gmail.com \
    --cc=v.shpilevoy@tarantool.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Tarantool development patches archive

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://lists.tarantool.org/tarantool-patches/0 tarantool-patches/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 tarantool-patches tarantool-patches/ https://lists.tarantool.org/tarantool-patches \
		tarantool-patches@dev.tarantool.org.
	public-inbox-index tarantool-patches

Example config snippet for mirrors.


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git