Take a look at this update XML:
<add>
<doc>
<field name="employeeId">05991</field>
<field name="employeeName">Steve McKay</field>
<field name="office" update="set">Walla Walla</field>
<field name="skills" update="add">Python</field>
</doc>
</add>
Let's say employeeId is the key. If there's a fourth field, salary, on the
existing doc, should it be deleted or retained? With this update it will
obviously be deleted:
<add>
<doc>
<field name="employeeId">05991</field>
<field name="employeeName">Steve McKay</field>
</doc>
</add>
With this XML it will be retained:
<add>
<doc>
<field name="employeeId">05991</field>
<field name="office" update="set">Walla Walla</field>
<field name="skills" update="add">Python</field>
</doc>
</add>
I'm not willing to guess what will happen in the case where non-atomic and
atomic updates are present on the same add because I haven't looked at that
code since 4.0, but I think I could make a case for retaining salary or for
discarding it. That by itself reeks--and it's also not well documented. Relying
on iffy, poorly-documented behavior is asking for pain at upgrade time.
Steve
On Jul 8, 2014, at 7:02 PM, Bill Au <bill.w...@gmail.com> wrote:
> Thanks for that under-the-cover explanation.
>
> I am not sure what you mean by "mix atomic updates with regular field
> values". Can you give an example?
>
> Thanks.
>
> Bill
>
>
> On Tue, Jul 8, 2014 at 6:56 PM, Steve McKay <st...@b.abbies.us> wrote:
>
>> Atomic updates fetch the doc with RealTimeGet, apply the updates to the
>> fetched doc, then reindex. Whether you use atomic updates or send the
>> entire doc to Solr, it has to deleteById then add. The perf difference
>> between the atomic updates and "normal" updates is likely minimal.
>>
>> Atomic updates are for when you have changes and want to apply them to a
>> document without affecting the other fields. A regular add will replace an
>> existing document completely. AFAIK Solr will let you mix atomic updates
>> with regular field values, but I don't think it's a good idea.
>>
>> Steve
>>
>> On Jul 8, 2014, at 5:30 PM, Bill Au <bill.w...@gmail.com> wrote:
>>
>>> Solr atomic update allows for changing only one or more fields of a
>>> document without having to re-index the entire document. But what about
>>> the case where I am sending in the entire document? In that case the
>> whole
>>> document will be re-indexed anyway, right? So I assume that there will
>> be
>>> no saving. I am actually thinking that there will be a performance
>> penalty
>>> since atomic update requires Solr to first retrieve all the fields first
>>> before updating.
>>>
>>> Bill
>>
>>
