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Posted to user@zookeeper.apache.org by Robert Rosolek <rr...@janestreet.com> on 2015/08/26 11:03:24 UTC
Get_children after create
Hi,
Sorry if this question was asked here before, but I couldn't find the
search functionality in the archives.
My question is the following: after create operation is successful, am I
guaranteed to
see the new child when doing get_children on the parent? I have a program,
that seems to be breaking because it makes this assumption. Looking at the
lock recipe at
https://github.com/apache/zookeeper/blob/trunk/src/recipes/lock/src/java/org/apache/zookeeper/recipes/lock/WriteLock.java,
it seems this code does *not* make this assumption and simply keeps
retrying in a tight loop until it finds the child.
Thank you,
Robert
Re: Get_children after create
Posted by Robert Rosolek <rr...@janestreet.com>.
I have found out what was causing the problem and, unsurprisingly, the bug
was on our side. Thank you for your help.
On Wed, Aug 26, 2015 at 1:35 PM, Flavio Junqueira <
fpjunqueira@yahoo.com.invalid> wrote:
> Hi Robert,
>
> If it is the same client that created the znode, then yes, it does read
> its own writes. A different client may not read it immediately because we
> propagate updates agreed upon to the replicas asynchronously. You could
> watch the parents for changes, though, and have the client being notified
> when the newly created child becomes visible for that client.
>
> -Flavio
>
> > On 26 Aug 2015, at 11:08, Robert Rosolek <rr...@janestreet.com>
> wrote:
> >
> > To clarify more: in my program no-one is deleting this node in the
> > meantime. Also the state of the zookeeper session is Connected all the
> time.
> >
> > On Wed, Aug 26, 2015 at 10:03 AM, Robert Rosolek <
> rrosolek@janestreet.com>
> > wrote:
> >
> >> Hi,
> >>
> >> Sorry if this question was asked here before, but I couldn't find the
> >> search functionality in the archives.
> >>
> >> My question is the following: after create operation is successful, am I
> >> guaranteed to
> >> see the new child when doing get_children on the parent? I have a
> program,
> >> that seems to be breaking because it makes this assumption. Looking at
> the
> >> lock recipe at
> >>
> https://github.com/apache/zookeeper/blob/trunk/src/recipes/lock/src/java/org/apache/zookeeper/recipes/lock/WriteLock.java
> ,
> >> it seems this code does *not* make this assumption and simply keeps
> >> retrying in a tight loop until it finds the child.
> >>
> >> Thank you,
> >> Robert
> >>
>
>
Re: Get_children after create
Posted by Flavio Junqueira <fp...@yahoo.com.INVALID>.
Hi Robert,
If it is the same client that created the znode, then yes, it does read its own writes. A different client may not read it immediately because we propagate updates agreed upon to the replicas asynchronously. You could watch the parents for changes, though, and have the client being notified when the newly created child becomes visible for that client.
-Flavio
> On 26 Aug 2015, at 11:08, Robert Rosolek <rr...@janestreet.com> wrote:
>
> To clarify more: in my program no-one is deleting this node in the
> meantime. Also the state of the zookeeper session is Connected all the time.
>
> On Wed, Aug 26, 2015 at 10:03 AM, Robert Rosolek <rr...@janestreet.com>
> wrote:
>
>> Hi,
>>
>> Sorry if this question was asked here before, but I couldn't find the
>> search functionality in the archives.
>>
>> My question is the following: after create operation is successful, am I
>> guaranteed to
>> see the new child when doing get_children on the parent? I have a program,
>> that seems to be breaking because it makes this assumption. Looking at the
>> lock recipe at
>> https://github.com/apache/zookeeper/blob/trunk/src/recipes/lock/src/java/org/apache/zookeeper/recipes/lock/WriteLock.java,
>> it seems this code does *not* make this assumption and simply keeps
>> retrying in a tight loop until it finds the child.
>>
>> Thank you,
>> Robert
>>
Re: Get_children after create
Posted by Robert Rosolek <rr...@janestreet.com>.
To clarify more: in my program no-one is deleting this node in the
meantime. Also the state of the zookeeper session is Connected all the time.
On Wed, Aug 26, 2015 at 10:03 AM, Robert Rosolek <rr...@janestreet.com>
wrote:
> Hi,
>
> Sorry if this question was asked here before, but I couldn't find the
> search functionality in the archives.
>
> My question is the following: after create operation is successful, am I
> guaranteed to
> see the new child when doing get_children on the parent? I have a program,
> that seems to be breaking because it makes this assumption. Looking at the
> lock recipe at
> https://github.com/apache/zookeeper/blob/trunk/src/recipes/lock/src/java/org/apache/zookeeper/recipes/lock/WriteLock.java,
> it seems this code does *not* make this assumption and simply keeps
> retrying in a tight loop until it finds the child.
>
> Thank you,
> Robert
>