Mailing-List: contact user-help@avro.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@avro.apache.org
Received-SPF: pass (nike.apache.org: domain of Robin.Mueller@1und1.de
 designates 212.227.126.201 as permitted sender)
Message-ID: <4C91D67C.7000707@1und1.de>
Date: Thu, 16 Sep 2010 10:34:04 +0200
From: =?ISO-8859-1?Q?Robin_M=FCller?= <Robin.Mueller@1und1.de>
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US;
 rv:1.9.1.12) Gecko/20100826 Lightning/1.0b1 Thunderbird/3.0.7
MIME-Version: 1.0
To: <user@avro.apache.org>
Subject: Re: Versioning of an array of a record
References: <4C91D0D5.5050601@1und1.de>
 <303B07CD-F59B-4876-93B7-D112E66F0EEE@richrelevance.com>
In-Reply-To: <303B07CD-F59B-4876-93B7-D112E66F0EEE@richrelevance.com>
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
Content-Transfer-Encoding: quoted-printable

Thanks for the fast reply.
I use the implementation for avro-serialization from voldemort=20
(key-value-store) and it seems that they don't use the ResolvingDecoder.=20
But I think there is a way to use an own implementation for the=20
serialization in voldemort. So I'll give it a try with the ResolvingDecoder=
.

Greetings,
Robin

Am 16.09.2010 10:21, schrieb Scott Carey:
> Assuming Java:  Are you using a ResolvingDecoder?
>
> This will happen by default if you are reading Generic or Specific record=
s from an Avro File, but if you are reading data otherwise, you have to use=
 a ResolvingDecoder to specify the expected (reader) and  actual (writer) s=
chemas.
>
> On Sep 16, 2010, at 1:09 AM, Robin M=FCller wrote:
>
>   =20
>> Hi,
>>
>> I've read the part "Schema Resolution" of the Avro Specification. So I
>> think that avro supports versioning of the schema.
>> But when I try to change to following schema, an AvroTypeException will
>> be thrown by reading data that was serialized with the old schema:
>> {
>>    "name":"BrowserCountArray",
>>    "type":"record",
>>    "fields": [
>>      {
>>      "name":"BrowserCounts",
>>      "type":
>>      {
>>        "type":"array",
>>        "items": {
>>          "name": "BrowserCount",
>>          "type": "record",
>>          "fields": [
>>            {
>>              "name":"Browser",
>>              "type":"string"
>>            }, {
>>              "name":"Count",
>>              "type":"int"
>>            }]
>>          }
>>        }
>>      }]
>> }
>>
>> For example I add a new field to the BrowserCount record like this:
>>
>> {
>>    "name":"BrowserCountArray",
>>    "type":"record",
>>    "fields": [
>>      {
>>      "name":"BrowserCounts",
>>      "type":
>>      {
>>        "type":"array",
>>        "items": {
>>          "name": "BrowserCount",
>>          "type": "record",
>>          "fields": [
>>            {
>>              "name":"Browser",
>>              "type":"string"
>>            }, {
>>              "name":"Count",
>>              "type":"int"
>>            }, {
>>              "name":"Blub",
>>              "type":"int",
>>              "default":"0"
>>            }]
>>          }
>>        }
>>      }]
>> }
>>
>> Is it possible to add or remove fields from this record and read with
>> this new schema data, that was serialized with an old one.
>> Or is there another way to define an array of record which solves that
>> problem.
>>
>> Thanks,
>> Robin
>>     =20
>   =20