[Tarantool-patches] [PATCH] txn_limbo: simplify owner migration condition

[Tarantool-patches] [PATCH] txn_limbo: simplify owner migration condition

[Cyrill Gorcunov via Tarantool-patches]

When limbo owner is about to change the state
we should check is if there are some pending
transactions are not yet processed, iow if
queue is empty. No need to test if current limbo
owner is zero. The owner is set to zero once --
when limbo is created during initialization.

After all I think even if owner would ever zero
and we're about to change it the queue simply
must be empty, that is the only safe state.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
Guys, I don't want to create a separate branch for this
small patch neither I consider it anyhow significant. More
likely it is a cleanup dropping redundant code. Discovered
while trying to figure out details of qsync.

 src/box/txn_limbo.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index addcb0f97..2a10bd0ae 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -94,8 +94,7 @@ txn_limbo_append(struct txn_limbo *limbo, uint32_t id, struct txn *txn)
 		id = instance_id;
 	bool make_ro = false;
 	if (limbo->owner_id != id) {
-		if (limbo->owner_id == REPLICA_ID_NIL ||
-		    rlist_empty(&limbo->queue)) {
+		if (rlist_empty(&limbo->queue)) {
 			limbo->owner_id = id;
 			limbo->confirmed_lsn = 0;
 			if (id != instance_id)
-- 
2.30.2

Re: [Tarantool-patches] [PATCH] txn_limbo: simplify owner migration condition

[Vladislav Shpilevoy via Tarantool-patches]

Hi! Thanks for the patch!

On 16.04.2021 00:06, Cyrill Gorcunov wrote:
> When limbo owner is about to change the state
> we should check is if there are some pending

'is' is not needed.

> transactions are not yet processed, iow if

are -> which are.

> queue is empty. No need to test if current limbo
> owner is zero. The owner is set to zero once --
> when limbo is created during initialization.
> 
> After all I think even if owner would ever zero
> and we're about to change it the queue simply
> must be empty, that is the only safe state.

[Tarantool-patches] [PATCH v2] txn_limbo: simplify owner migration condition

[Cyrill Gorcunov via Tarantool-patches]

When limbo owner is about to change the state we should check
if there are some pending transactions which are not yet processed,
iow if queue is empty. No need to test if current limbo owner
is zero. The owner is set to zero once -- when limbo is created
during initialization.

After all I think even if owner would ever zero and we're about
to change it the queue simply must be empty, that is the only
safe state.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
 src/box/txn_limbo.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: tarantool.git/src/box/txn_limbo.c
===================================================================
--- tarantool.git.orig/src/box/txn_limbo.c
+++ tarantool.git/src/box/txn_limbo.c
@@ -94,8 +94,7 @@ txn_limbo_append(struct txn_limbo *limbo
 		id = instance_id;
 	bool make_ro = false;
 	if (limbo->owner_id != id) {
-		if (limbo->owner_id == REPLICA_ID_NIL ||
-		    rlist_empty(&limbo->queue)) {
+		if (rlist_empty(&limbo->queue)) {
 			limbo->owner_id = id;
 			limbo->confirmed_lsn = 0;
 			if (id != instance_id)

Re: [Tarantool-patches] [PATCH v2] txn_limbo: simplify owner migration condition

[Vladislav Shpilevoy via Tarantool-patches]

Hi! Thanks for the patch!

LGTM. But I am afraid you still need to create a branch. We
don't commit patches from mail usually.

Re: [Tarantool-patches] [PATCH v2] txn_limbo: simplify owner migration condition

[Cyrill Gorcunov via Tarantool-patches]

On Fri, Apr 16, 2021 at 09:29:10PM +0200, Vladislav Shpilevoy wrote:
> Hi! Thanks for the patch!
> 
> LGTM. But I am afraid you still need to create a branch. We
> don't commit patches from mail usually.

Thanks, Vlad! I'll collect a few more cleanups and send out on
te next week. This one simply with you Ack applied.