答复: Lock and Failed to unlock keys exception

[Shawn Du <sh...@neulion.com.cn>]

Fixed by myself.

There are two errors in my code/configuration.

1) lock are only supported in TRANSACTIONAL mode. I missed it in my
configuration.
2) within a lock block, can't start cache:
  IgniteCache<String, NamedSequence> cache =
ignite.cache(NamedSequence.CACHE_NAME_ID);
  
  Above code should be called out of the lock block.

Thanks
Shawn

-----邮件原件-----
发件人: Shawn Du [mailto:shawn.du@neulion.com.cn] 
发送时间: 2016年11月24日 14:20
收件人: user@ignite.apache.org
主题: Lock and Failed to unlock keys exception

Hi,

I am trying to implement distributed ID generators using lock and caches. 

I wrote some codes like this, but it always throw exception "Failed to
unlock keys exception". 
The code may runs in different JVM/hosts.

Do I misuse the lock feature?  Thanks in advance.

----------------------------------------------------
Lock lock = osCache.lock(Os.CACHE_LOCK); try {
	lock.lock();
	os = osCache.get(videoMessage.os());
	if (os == null)
	{
		os = new Os(videoMessage.os(),
idGenerator.next(Os.class.getName()));
		osCache.put(os.getName(), os);
	}
	videoMessage.os(os.getId() + "");
}
finally
{
	lock.unlock();
}

-------------------------------------------------------End
IdGenerator.next looks like this:
-------------------------------------------------------
public int next(String name)
{
	IgniteCache<String, NamedSequence> cache =
ignite.cache(NamedSequence.CACHE_NAME_ID);
	NamedSequence sequence = cache.get(name);
	if (sequence == null)
	{
		sequence = new NamedSequence(name);
	}
	else
	{
		sequence.increase();
	}
	cache.put(sequence.getName(), sequence);
	return sequence.getSequence();
}
----------------------------------------------------------

Re: Lock and Failed to unlock keys exception

[Denis Magda <dm...@apache.org>]

Just want to let you know that Ignite already provide a highly performant and stable implementation of a distributed ID generator
https://apacheignite.readme.io/docs/id-generator <https://apacheignite.readme.io/docs/id-generator>

—
Denis

> On Nov 23, 2016, at 11:11 PM, Shawn Du <sh...@neulion.com.cn> wrote:
> 
> Fixed by myself.
> 
> There are two errors in my code/configuration.
> 
> 1) lock are only supported in TRANSACTIONAL mode. I missed it in my
> configuration.
> 2) within a lock block, can't start cache:
>  IgniteCache<String, NamedSequence> cache =
> ignite.cache(NamedSequence.CACHE_NAME_ID);
> 
>  Above code should be called out of the lock block.
> 
> Thanks
> Shawn
> 
> -----邮件原件-----
> 发件人: Shawn Du [mailto:shawn.du@neulion.com.cn] 
> 发送时间: 2016年11月24日 14:20
> 收件人: user@ignite.apache.org
> 主题: Lock and Failed to unlock keys exception
> 
> Hi,
> 
> I am trying to implement distributed ID generators using lock and caches. 
> 
> I wrote some codes like this, but it always throw exception "Failed to
> unlock keys exception". 
> The code may runs in different JVM/hosts.
> 
> Do I misuse the lock feature?  Thanks in advance.
> 
> ----------------------------------------------------
> Lock lock = osCache.lock(Os.CACHE_LOCK); try {
> 	lock.lock();
> 	os = osCache.get(videoMessage.os());
> 	if (os == null)
> 	{
> 		os = new Os(videoMessage.os(),
> idGenerator.next(Os.class.getName()));
> 		osCache.put(os.getName(), os);
> 	}
> 	videoMessage.os(os.getId() + "");
> }
> finally
> {
> 	lock.unlock();
> }
> 
> -------------------------------------------------------End
> IdGenerator.next looks like this:
> -------------------------------------------------------
> public int next(String name)
> {
> 	IgniteCache<String, NamedSequence> cache =
> ignite.cache(NamedSequence.CACHE_NAME_ID);
> 	NamedSequence sequence = cache.get(name);
> 	if (sequence == null)
> 	{
> 		sequence = new NamedSequence(name);
> 	}
> 	else
> 	{
> 		sequence.increase();
> 	}
> 	cache.put(sequence.getName(), sequence);
> 	return sequence.getSequence();
> }
> ----------------------------------------------------------
>