We noticed that IndexedDocIterator.java has the following private static
fields:

    private static Text indexColf = DEFAULT_INDEX_COLF;
    private static Text docColf = DEFAULT_DOC_COLF;

The init method, which sets these is synchronized.  Still, though, this
synchronization doesn't seem enough to allow different runs of the iterator to
use different values for indexColf and docColf.  One run will set the "Colf"
variables one way atomically in the synchronized init method. . . and another
run and immediately interleave in alternate "Colf" settings, which breaks the
original iterator run.

For now, we're not touching the indexColf and docColf, just leaving it as the
defaults.

We're not blocked by this.  We're just curious if there's a bug in this design.
Also, if it's not a defect, we're interested in learning what system invariant
of iterator execution makes this not a problem.

Thanks,
Sukant

On Mon, Nov 5, 2012 at 11:24 AM, Sukant Hajra <[EMAIL PROTECTED]>wrote:

> We noticed that IndexedDocIterator.java has the following private static
> fields:
>
>     private static Text indexColf = DEFAULT_INDEX_COLF;
>     private static Text docColf = DEFAULT_DOC_COLF;
>
> The init method, which sets these is synchronized.  Still, though, this
> synchronization doesn't seem enough to allow different runs of the
> iterator to
> use different values for indexColf and docColf.  One run will set the
> "Colf"
> variables one way atomically in the synchronized init method. . . and
> another
> run and immediately interleave in alternate "Colf" settings, which breaks
> the
> original iterator run.
>
> For now, we're not touching the indexColf and docColf, just leaving it as
> the
> defaults.
>
> We're not blocked by this.  We're just curious if there's a bug in this
> design.
> Also, if it's not a defect, we're interested in learning what system
> invariant
> of iterator execution makes this not a problem.
>

Sounds like a bug.  Feel free to open a ticket!

Billie

>
> Thanks,
> Sukant
>

At one point, Keith had warned me against kicking off threads inside a scan
session. Is it possible we could have a discussion on the implications of
this?

On Mon, Nov 5, 2012 at 11:30 AM, Billie Rinaldi <[EMAIL PROTECTED]> wrote:

> On Mon, Nov 5, 2012 at 11:24 AM, Sukant Hajra <[EMAIL PROTECTED]>wrote:
>
>> We noticed that IndexedDocIterator.java has the following private static
>> fields:
>>
>>     private static Text indexColf = DEFAULT_INDEX_COLF;
>>     private static Text docColf = DEFAULT_DOC_COLF;
>>
>> The init method, which sets these is synchronized.  Still, though, this
>> synchronization doesn't seem enough to allow different runs of the
>> iterator to
>> use different values for indexColf and docColf.  One run will set the
>> "Colf"
>> variables one way atomically in the synchronized init method. . . and
>> another
>> run and immediately interleave in alternate "Colf" settings, which breaks
>> the
>> original iterator run.
>>
>> For now, we're not touching the indexColf and docColf, just leaving it as
>> the
>> defaults.
>>
>> We're not blocked by this.  We're just curious if there's a bug in this
>> design.
>> Also, if it's not a defect, we're interested in learning what system
>> invariant
>> of iterator execution makes this not a problem.
>>
>
> Sounds like a bug.  Feel free to open a ticket!
>
> Billie
>
>
>
>>
>> Thanks,
>> Sukant
>>
>
>

On Mon, Nov 5, 2012 at 3:29 PM, William Slacum
<[EMAIL PROTECTED]> wrote:
> At one point, Keith had warned me against kicking off threads inside a scan
> session. Is it possible we could have a discussion on the implications of
> this?

I think this is a slightly different issue.  The iterator is not
kicking off other threads.  The iterator does not seem to be safe to
use when there are concurrent scans using it on a single tablet
server.

There are two other static fields that seem suspicious,  indexColfSet
and docColfSet.

Keith

>
>
> On Mon, Nov 5, 2012 at 11:30 AM, Billie Rinaldi <[EMAIL PROTECTED]> wrote:
>>
>> On Mon, Nov 5, 2012 at 11:24 AM, Sukant Hajra <[EMAIL PROTECTED]>
>> wrote:
>>>
>>> We noticed that IndexedDocIterator.java has the following private static
>>> fields:
>>>
>>>     private static Text indexColf = DEFAULT_INDEX_COLF;
>>>     private static Text docColf = DEFAULT_DOC_COLF;
>>>
>>> The init method, which sets these is synchronized.  Still, though, this
>>> synchronization doesn't seem enough to allow different runs of the
>>> iterator to
>>> use different values for indexColf and docColf.  One run will set the
>>> "Colf"
>>> variables one way atomically in the synchronized init method. . . and
>>> another
>>> run and immediately interleave in alternate "Colf" settings, which breaks
>>> the
>>> original iterator run.
>>>
>>> For now, we're not touching the indexColf and docColf, just leaving it as
>>> the
>>> defaults.
>>>
>>> We're not blocked by this.  We're just curious if there's a bug in this
>>> design.
>>> Also, if it's not a defect, we're interested in learning what system
>>> invariant
>>> of iterator execution makes this not a problem.
>>
>>
>> Sounds like a bug.  Feel free to open a ticket!
>>
>> Billie
>>
>>
>>>
>>>
>>> Thanks,
>>> Sukant
>>
>>
>