Changing TDB File Mode on an existing index, in 2.7.11?

[Matthew Holt <ma...@mpholt.com>]

Hi,
Wanted to check if anyone can confirm if you can successfully change the
TDB File Mode in 2.7.11 from direct to mapped (assuming a restart takes
place) , or vice-versa, without any issues?

We've read that this is supported, and tried this without any issues, but
received some push back as at one time this was an issue.

Thanks for any help you can provide,
Matt

Re: Changing TDB File Mode on an existing index, in 2.7.11?

[Matthew Holt <ma...@mpholt.com>]

On Thu, Jan 28, 2016 at 1:10 PM, Andy Seaborne <an...@apache.org> wrote:

> On 28/01/16 16:52, Matthew Holt wrote:
>
>> Hi Andy,
>> Thanks for the reply. Responding in-line below...
>>
>> On Thu, Jan 28, 2016 at 4:26 AM, Andy Seaborne <an...@apache.org> wrote:
>>
>> On 27/01/16 21:45, Matthew Holt wrote:
>>>
>>> Hi,
>>>> Wanted to check if anyone can confirm if you can successfully change the
>>>> TDB File Mode in 2.7.11
>>>>
>>>>
>>> 2.7.1?
>>>
>>
>>
>> That's correct, I had that listed incorrectly there.
>>
>>
>>>
>>> from direct to mapped (assuming a restart takes
>>>
>>>> place) , or vice-versa, without any issues?
>>>>
>>>>
>>> You can do that.
>>>
>>> (though upgrading would be a good idea)
>>>
>>> We've read that this is supported, and tried this without any issues, but
>>>
>>>> received some push back as at one time this was an issue.
>>>>
>>>>
>>> What was the issue?
>>>
>>
>>
>> At this point not too sure. They encountered this issue around 5 years
>> ago,
>>
>
> Depends on who "they" are.
>
> (If it happens to be IBM ...)
>
> There is one issue that arises ... MS Windows does not allow memory mapped
> files to be deleted without exiting the JVM.  This is a long standing Java
> issue for Sun/Oracle/OpenJDK JVMs.
>
> But direct mode vs mapped mode is reported as not much of a performance
> win on Windows  anyway.


Thanks Andy. Good call there. :)

That's one issue we were aware of, and for now, only enabling it for Linux
64 bit users.

We hadn't seen any issue in our testing, but found a long-ago defect
talking about that a potential issue, so had wanted to make sure we could
be more confident with the switch over.

Thanks again,
Matt

>
>
>     Andy
>
>
> and put code in place so that it would only use the File IO mode the
>> indices were created with. We have only been using Direct, and are now
>> switching to Mapped IO for systems that support it to take advantage of
>> performance benefits.
>>
>>
>> Thanks again for your help,
>> Matt
>>
>>
>>
>>>
>>>          Andy
>>>
>>>
>>>
>>> Thanks for any help you can provide,
>>>> Matt
>>>>
>>>>
>>>>
>>>
>>
>

Re: Changing TDB File Mode on an existing index, in 2.7.11?

[Andy Seaborne <an...@apache.org>]

On 28/01/16 16:52, Matthew Holt wrote:
> Hi Andy,
> Thanks for the reply. Responding in-line below...
>
> On Thu, Jan 28, 2016 at 4:26 AM, Andy Seaborne <an...@apache.org> wrote:
>
>> On 27/01/16 21:45, Matthew Holt wrote:
>>
>>> Hi,
>>> Wanted to check if anyone can confirm if you can successfully change the
>>> TDB File Mode in 2.7.11
>>>
>>
>> 2.7.1?
>
>
> That's correct, I had that listed incorrectly there.
>
>>
>>
>> from direct to mapped (assuming a restart takes
>>> place) , or vice-versa, without any issues?
>>>
>>
>> You can do that.
>>
>> (though upgrading would be a good idea)
>>
>> We've read that this is supported, and tried this without any issues, but
>>> received some push back as at one time this was an issue.
>>>
>>
>> What was the issue?
>
>
> At this point not too sure. They encountered this issue around 5 years ago,

Depends on who "they" are.

(If it happens to be IBM ...)

There is one issue that arises ... MS Windows does not allow memory 
mapped files to be deleted without exiting the JVM.  This is a long 
standing Java issue for Sun/Oracle/OpenJDK JVMs.

But direct mode vs mapped mode is reported as not much of a performance 
win on Windows  anyway.

     Andy

> and put code in place so that it would only use the File IO mode the
> indices were created with. We have only been using Direct, and are now
> switching to Mapped IO for systems that support it to take advantage of
> performance benefits.
>
>
> Thanks again for your help,
> Matt
>
>
>>
>>
>>          Andy
>>
>>
>>
>>> Thanks for any help you can provide,
>>> Matt
>>>
>>>
>>
>

Re: Changing TDB File Mode on an existing index, in 2.7.11?

[Matthew Holt <ma...@mpholt.com>]

Hi Andy,
Thanks for the reply. Responding in-line below...

On Thu, Jan 28, 2016 at 4:26 AM, Andy Seaborne <an...@apache.org> wrote:

> On 27/01/16 21:45, Matthew Holt wrote:
>
>> Hi,
>> Wanted to check if anyone can confirm if you can successfully change the
>> TDB File Mode in 2.7.11
>>
>
> 2.7.1?


That's correct, I had that listed incorrectly there.

>
>
> from direct to mapped (assuming a restart takes
>> place) , or vice-versa, without any issues?
>>
>
> You can do that.
>
> (though upgrading would be a good idea)
>
> We've read that this is supported, and tried this without any issues, but
>> received some push back as at one time this was an issue.
>>
>
> What was the issue?


At this point not too sure. They encountered this issue around 5 years ago,
and put code in place so that it would only use the File IO mode the
indices were created with. We have only been using Direct, and are now
switching to Mapped IO for systems that support it to take advantage of
performance benefits.


Thanks again for your help,
Matt


>
>
>         Andy
>
>
>
>> Thanks for any help you can provide,
>> Matt
>>
>>
>

Re: Changing TDB File Mode on an existing index, in 2.7.11?

[Andy Seaborne <an...@apache.org>]

On 27/01/16 21:45, Matthew Holt wrote:
> Hi,
> Wanted to check if anyone can confirm if you can successfully change the
> TDB File Mode in 2.7.11

2.7.1?

>from direct to mapped (assuming a restart takes
> place) , or vice-versa, without any issues?

You can do that.

(though upgrading would be a good idea)

> We've read that this is supported, and tried this without any issues, but
> received some push back as at one time this was an issue.

What was the issue?

	Andy

>
> Thanks for any help you can provide,
> Matt
>