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Posted to user@ignite.apache.org by Lijun Cao <64...@qq.com> on 2018/07/30 07:30:34 UTC
Questions about how Ignite SQL Works
Hi:
I have referenced How Ignite SQL Works document but I still have got 2 questions.
The first question is, when I load data to Ignite cluster(3 nodes) in first time, the data is stored both on RAM and disk(I enabled local persistence), so which area does Ignite query on in this situation?
The second question is, when I restart the cluster which I have mentioned above, the data is still on disk, but not exists in the RAM, so how can I load the data from disk to RAM in this situation?
Look for your reply :-).
Re: Questions about how Ignite SQL Works
Posted by Lijun Cao <64...@qq.com>.
Okay, thank you.
> 在 2018年7月30日，15:32，Prem Prakash Sharma <prem@infoworks.io <ma...@infoworks.io>> 写道：
>
> Don't know about the first question but if you have persistence enabled ignite will load the data on startup
>
> Regards,
> Prem
>
> On Mon, Jul 30, 2018, 1:00 PM Lijun Cao <641507577@qq.com <ma...@qq.com>> wrote:
> Hi:
>
> I have referenced How Ignite SQL Works document but I still have got 2 questions.
>
> The first question is, when I load data to Ignite cluster(3 nodes) in first time, the data is stored both on RAM and disk(I enabled local persistence), so which area does Ignite query on in this situation?
>
> The second question is, when I restart the cluster which I have mentioned above, the data is still on disk, but not exists in the RAM, so how can I load the data from disk to RAM in this situation?
>
> Look for your reply :-).
Re: Questions about how Ignite SQL Works
Posted by Prem Prakash Sharma <pr...@infoworks.io>.
Don't know about the first question but if you have persistence enabled
ignite will load the data on startup
Regards,
Prem
On Mon, Jul 30, 2018, 1:00 PM Lijun Cao <64...@qq.com> wrote:
> Hi:
>
> I have referenced *How Ignite SQL Works *document but I still have got 2
> questions.
>
> The first question is, when I load data to Ignite cluster(3 nodes) in
> first time, the data is stored both on RAM and disk(I enabled local
> persistence), so which area does Ignite query on in this situation?
>
> The second question is, when I restart the cluster which I have mentioned
> above, the data is still on disk, but not exists in the RAM, so how can I
> load the data from disk to RAM in this situation?
>
> Look for your reply :-).
>
Re: Questions about how Ignite SQL Works
Posted by Lijun Cao <64...@qq.com>.
I get it. Thank you for answering my question Mikael :-) .
> 在 2018年7月30日，16:18，Mikael <mi...@telia.com> 写道：
>
> Hi!
>
> With native persistence enabled it's all done for you, a query will search both ram and disk contents and at a restart Ignite will load "missing" data from disk when needed, so if you do an SQL query it will load any data from disk if it should be included in the result, for the query point of view it's no difference if you have (native) persistence enabled or not, it works the same way.
>
> Mikael
>
> Den 2018-07-30 kl. 09:30, skrev Lijun Cao:
>> Hi:
>>
>> I have referenced How Ignite SQL Works document but I still have got 2 questions.
>>
>> The first question is, when I load data to Ignite cluster(3 nodes) in first time, the data is stored both on RAM and disk(I enabled local persistence), so which area does Ignite query on in this situation?
>>
>> The second question is, when I restart the cluster which I have mentioned above, the data is still on disk, but not exists in the RAM, so how can I load the data from disk to RAM in this situation?
>>
>> Look for your reply :-).
>
Re: Questions about how Ignite SQL Works
Posted by Mikael <mi...@telia.com>.
Hi!
With native persistence enabled it's all done for you, a query will
search both ram and disk contents and at a restart Ignite will load
"missing" data from disk when needed, so if you do an SQL query it will
load any data from disk if it should be included in the result, for the
query point of view it's no difference if you have (native) persistence
enabled or not, it works the same way.
Mikael
Den 2018-07-30 kl. 09:30, skrev Lijun Cao:
> Hi:
>
> I have referenced *How Ignite SQL Works *document but I still have got
> 2 questions.
>
> The first question is, when I load data to Ignite cluster(3 nodes) in
> first time, the data is stored both on RAM and disk(I enabled local
> persistence), so which area does Ignite query on in this situation?
>
> The second question is, when I restart the cluster which I have
> mentioned above, the data is still on disk, but not exists in the RAM,
> so how can I load the data from disk to RAM in this situation?
>
> Look for your reply :-).