You are viewing a plain text version of this content. The canonical link for it is here.
Posted to user@cassandra.apache.org by Frank LoVecchio <fr...@isidorey.com> on 2010/12/01 21:19:52 UTC
Range Queries in RP on SCF in 0.7 with UUID SCs
Is it possible to perform paginated queries using Random Partitioner in 0.7
with Super Column Families whose Super Columns are UUID's? I don't believe
it is, based on this article:
http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner,
and my attempts with Pelops.
Let's say I get the last 25 inserts for a key. I now know the 25th Super
Column UUID, and I want to start from there and get the next 25 inserts. Do
I have to change over to Order Preserving Partitioner? I'd like to avoid
this at all costs.
Thanks,
Frank
Re: Range Queries in RP on SCF in 0.7 with UUID SCs
Posted by Dan Washusen <da...@reactive.org>.
Using the methods on the Bytes class would be preferable. The byte[]
related methods on UuidHelper should have been deprecated with the Bytes
class was introduced...
e.g. new Bytes(col.getName()).toUuid()
Cheers,
Dan
On Thu, Dec 2, 2010 at 10:26 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
> Actually, it was a class issue at this line:
>
> System.*out*.println("NAME: " + UUID.*nameUUIDFromBytes*(col.getName()));
>
> The native Pelops class timeUuidHelper is what should be used.
>
> On Wed, Dec 1, 2010 at 4:16 PM, Aaron Morton <aa...@thelastpickle.com>wrote:
>
>> When you say "I want to get rows starting from a Super Column..." it's a
>> bit confusing. Do you want to get super columns from a single row, or
>> multiple rows? I'm assuming you are talking about getting columns from a
>> single row / key as that's what your code does.
>>
>> For the pelops code, it looks OK but I've not used Pelops. You can turn
>> the logging up on the server and check the command that is sent to it. I'm
>> would guess there is something wrong with the way you are transforming the
>> start key
>>
>> For your cli example what was the command you executed ?
>>
>> Aaron
>>
>> On 02 Dec, 2010,at 11:03 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
>>
>> Hey Aaron,
>>
>>
>> Yes, in regards to SCF definition, you are correct:
>>
>>
>> name: Sensor
>>
>> column_type: Super
>>
>> compare_with: TimeUUIDType
>>
>> gc_grace_seconds: 864000
>>
>> keys_cached: 10000.0
>>
>> read_repair_chance: 1.0
>>
>> rows_cached: 0.0
>>
>> I'm not quite sure I follow you, though, as I think I'm doing what you
>> specify. The Pelops code is below. Basically, I want to get rows
>> starting from a Super Column with a specific UUID and limit the number, just
>> as you inferred. When I run this code I just get the last N values (25 in
>> this case) if non-reversed, and the first N values if reversed. However,
>> regardless of what start param we use (Super Column UUID is String startKey
>> below), we still get the same values for the specified amount (e.g. the same
>> 25).
>>
>> *public* *void* getSuperRowKeys(String rowKey, String columnFamily, *int* limit,
>> String startKey) *throws* Exception {
>>
>> *byte*[] byteArray = UuidHelper.*timeUuidStringToBytes*(startKey);
>>
>> ByteBuffer bb = ByteBuffer.*wrap*(byteArray);
>>
>> *new* UUID (bb.getLong(), bb.getLong());
>>
>> List<SuperColumn> cols = selector.getPageOfSuperColumnsFromRow(columnFamily,
>> rowKey, Bytes.*fromByteBuffer*(bb), *false*, limit, ConsistencyLevel.*ONE
>> *);
>>
>>
>> *for* (SuperColumn col : cols) {
>>
>> *if* (col.getName() != *null*) {
>>
>>
>> System.*out*.println("NAME: " + UUID.*nameUUIDFromBytes*
>> (col.getName()));
>>
>>
>> *for* (Column c : col.columns) {
>>
>> System.*out*.println("\t\tName: " + Bytes.*toUTF8*(c.getName())
>>
>> + " Value: " + Bytes.*toUTF8*(c.getValue())
>>
>> + " timestamp: " + c.timestamp);
>>
>>
>> }
>>
>>
>> }
>>
>> }
>>
>>
>> }
>>
>> Here is some example data from the CLI. If we specify 2f814d30-f758-11df-2f81-4d30f75811df
>> as the start param (second super column down), we still get 52e6540-f759-11df-952e-6540f75911df
>> (first super column) returned.
>>
>> => (super_column=952e6540-f759-11df-952e-6540f75911df,
>> (column=64617465,
>> value=323031302d31312d32332032333a32393a30332e303030,
>> timestamp=1290554997141000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290554997141000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290554997141000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290554997141000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290554997141000)
>> (column=737461747573, value=5550, timestamp=1290554997141000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290554997141000))
>> => (super_column=2f814d30-f758-11df-2f81-4d30f75811df,
>> (column=64617465,
>> value=323031302d31312d32332032333a31393a30332e303030,
>> timestamp=1290554397060000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290554397060000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290554397060000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290554397060000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290554397060000)
>> (column=737461747573, value=5550, timestamp=1290554397060000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290554397060000))
>> => (super_column=7c959f00-f757-11df-7c95-9f00f75711df,
>> (column=64617465,
>> value=323031302d31312d32332032333a31343a30332e303030,
>> timestamp=1290554096881000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290554096881000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290554096881000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290554096881000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290554096881000)
>> (column=737461747573, value=5550, timestamp=1290554096881000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290554096881000))
>> => (super_column=c9be6330-f756-11df-c9be-6330f75611df,
>> (column=64617465,
>> value=323031302d31312d32332032333a30393a30332e303030,
>> timestamp=1290553796836000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290553796836000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290553796836000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290553796836000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290553796836000)
>> (column=737461747573, value=5550, timestamp=1290553796836000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290553796836000))
>> => (super_column=17108150-f756-11df-1710-8150f75611df,
>> (column=64617465,
>> value=323031302d31312d32332032333a30343a30332e303030,
>> timestamp=1290553497067000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290553497067000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290553497067000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290553497067000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290553497067000)
>> (column=737461747573, value=5550, timestamp=1290553497067000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290553497067000))
>> => (super_column=641da730-f755-11df-641d-a730f75511df,
>> (column=64617465,
>> value=323031302d31312d32332032323a35393a30332e303030,
>> timestamp=1290553196836000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290553196836000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290553196836000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290553196836000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290553196836000)
>> (column=737461747573, value=5550, timestamp=1290553196836000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290553196836000))
>> => (super_column=4bce9420-f753-11df-4bce-9420f75311df,
>> (column=64617465,
>> value=323031302d31312d32332032323a34343a30332e303030,
>> timestamp=1290552297060000)
>> (column=65787472615f696e666f, value=6e6f6e65,
>> timestamp=1290552297060000)
>> (column=726561736f6e, value=6e6f6e65, timestamp=1290552297060000)
>> (column=7365636f6e64735f746f5f6e657874, value=373530,
>> timestamp=1290552297060000)
>> (column=73657269616c, value=393135353032353731,
>> timestamp=1290552297060000)
>> (column=737461747573, value=5550, timestamp=1290552297060000)
>> (column=74797065, value=486561727462656174,
>> timestamp=1290552297060000))
>>
>> On Wed, Dec 1, 2010 at 2:25 PM, Aaron Morton <aa...@thelastpickle.com>wrote:
>>
>>> The Partitioner applies to the row keys, not the columns. Their order is
>>> determined by the compare_with and compare_subcolumns_with CF settings
>>>
>>> So where you say "get the last 25 inserts for a key" I'm translating that
>>> into "get the most recent 25 super columns for a row, where the super column
>>> names are UUID's and the CF definition has compare_with: TimeUUIDType"
>>>
>>> You can send a get_slice where the SliceRange has count=25 and
>>> reversed=True. If you know the 25th col name you can use it as the start
>>> param, and AFAIK the operation would go faster Not sure how this translates
>>> into calls against Pelops.
>>>
>>> This assumes you are using time / v1 UUID's that have an increasing
>>> order.
>>>
>>> Hope that helps.
>>>
>>> Aaron
>>>
>>>
>>>
>>> On 02 Dec, 2010,at 09:19 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
>>>
>>> Is it possible to perform paginated queries using Random Partitioner in
>>> 0.7 with Super Column Families whose Super Columns are UUID's? I don't
>>> believe it is, based on this article:
>>> http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner,
>>> and my attempts with Pelops.
>>>
>>> Let's say I get the last 25 inserts for a key. I now know the 25th Super
>>> Column UUID, and I want to start from there and get the next 25 inserts. Do
>>> I have to change over to Order Preserving Partitioner? I'd like to avoid
>>> this at all costs.
>>>
>>> Thanks,
>>>
>>> Frank
>>>
>>>
>>
>
Re: Range Queries in RP on SCF in 0.7 with UUID SCs
Posted by Frank LoVecchio <fr...@isidorey.com>.
Actually, it was a class issue at this line:
System.*out*.println("NAME: " + UUID.*nameUUIDFromBytes*(col.getName()));
The native Pelops class timeUuidHelper is what should be used.
On Wed, Dec 1, 2010 at 4:16 PM, Aaron Morton <aa...@thelastpickle.com>wrote:
> When you say "I want to get rows starting from a Super Column..." it's a
> bit confusing. Do you want to get super columns from a single row, or
> multiple rows? I'm assuming you are talking about getting columns from a
> single row / key as that's what your code does.
>
> For the pelops code, it looks OK but I've not used Pelops. You can turn the
> logging up on the server and check the command that is sent to it. I'm would
> guess there is something wrong with the way you are transforming the start
> key
>
> For your cli example what was the command you executed ?
>
> Aaron
>
> On 02 Dec, 2010,at 11:03 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
>
> Hey Aaron,
>
>
> Yes, in regards to SCF definition, you are correct:
>
>
> name: Sensor
>
> column_type: Super
>
> compare_with: TimeUUIDType
>
> gc_grace_seconds: 864000
>
> keys_cached: 10000.0
>
> read_repair_chance: 1.0
>
> rows_cached: 0.0
>
> I'm not quite sure I follow you, though, as I think I'm doing what you
> specify. The Pelops code is below. Basically, I want to get rows
> starting from a Super Column with a specific UUID and limit the number, just
> as you inferred. When I run this code I just get the last N values (25 in
> this case) if non-reversed, and the first N values if reversed. However,
> regardless of what start param we use (Super Column UUID is String startKey
> below), we still get the same values for the specified amount (e.g. the same
> 25).
>
> *public* *void* getSuperRowKeys(String rowKey, String columnFamily, *int* limit,
> String startKey) *throws* Exception {
>
> *byte*[] byteArray = UuidHelper.*timeUuidStringToBytes*(startKey);
>
> ByteBuffer bb = ByteBuffer.*wrap*(byteArray);
>
> *new* UUID (bb.getLong(), bb.getLong());
>
> List<SuperColumn> cols = selector.getPageOfSuperColumnsFromRow(columnFamily,
> rowKey, Bytes.*fromByteBuffer*(bb), *false*, limit, ConsistencyLevel.*ONE*
> );
>
>
> *for* (SuperColumn col : cols) {
>
> *if* (col.getName() != *null*) {
>
>
> System.*out*.println("NAME: " + UUID.*nameUUIDFromBytes*(col.getName()));
>
>
> *for* (Column c : col.columns) {
>
> System.*out*.println("\t\tName: " + Bytes.*toUTF8*(c.getName())
>
> + " Value: " + Bytes.*toUTF8*(c.getValue())
>
> + " timestamp: " + c.timestamp);
>
>
> }
>
>
> }
>
> }
>
>
> }
>
> Here is some example data from the CLI. If we specify 2f814d30-f758-11df-2f81-4d30f75811df
> as the start param (second super column down), we still get 52e6540-f759-11df-952e-6540f75911df
> (first super column) returned.
>
> => (super_column=952e6540-f759-11df-952e-6540f75911df,
> (column=64617465,
> value=323031302d31312d32332032333a32393a30332e303030,
> timestamp=1290554997141000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290554997141000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290554997141000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290554997141000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290554997141000)
> (column=737461747573, value=5550, timestamp=1290554997141000)
> (column=74797065, value=486561727462656174,
> timestamp=1290554997141000))
> => (super_column=2f814d30-f758-11df-2f81-4d30f75811df,
> (column=64617465,
> value=323031302d31312d32332032333a31393a30332e303030,
> timestamp=1290554397060000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290554397060000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290554397060000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290554397060000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290554397060000)
> (column=737461747573, value=5550, timestamp=1290554397060000)
> (column=74797065, value=486561727462656174,
> timestamp=1290554397060000))
> => (super_column=7c959f00-f757-11df-7c95-9f00f75711df,
> (column=64617465,
> value=323031302d31312d32332032333a31343a30332e303030,
> timestamp=1290554096881000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290554096881000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290554096881000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290554096881000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290554096881000)
> (column=737461747573, value=5550, timestamp=1290554096881000)
> (column=74797065, value=486561727462656174,
> timestamp=1290554096881000))
> => (super_column=c9be6330-f756-11df-c9be-6330f75611df,
> (column=64617465,
> value=323031302d31312d32332032333a30393a30332e303030,
> timestamp=1290553796836000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290553796836000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290553796836000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290553796836000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290553796836000)
> (column=737461747573, value=5550, timestamp=1290553796836000)
> (column=74797065, value=486561727462656174,
> timestamp=1290553796836000))
> => (super_column=17108150-f756-11df-1710-8150f75611df,
> (column=64617465,
> value=323031302d31312d32332032333a30343a30332e303030,
> timestamp=1290553497067000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290553497067000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290553497067000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290553497067000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290553497067000)
> (column=737461747573, value=5550, timestamp=1290553497067000)
> (column=74797065, value=486561727462656174,
> timestamp=1290553497067000))
> => (super_column=641da730-f755-11df-641d-a730f75511df,
> (column=64617465,
> value=323031302d31312d32332032323a35393a30332e303030,
> timestamp=1290553196836000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290553196836000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290553196836000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290553196836000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290553196836000)
> (column=737461747573, value=5550, timestamp=1290553196836000)
> (column=74797065, value=486561727462656174,
> timestamp=1290553196836000))
> => (super_column=4bce9420-f753-11df-4bce-9420f75311df,
> (column=64617465,
> value=323031302d31312d32332032323a34343a30332e303030,
> timestamp=1290552297060000)
> (column=65787472615f696e666f, value=6e6f6e65,
> timestamp=1290552297060000)
> (column=726561736f6e, value=6e6f6e65, timestamp=1290552297060000)
> (column=7365636f6e64735f746f5f6e657874, value=373530,
> timestamp=1290552297060000)
> (column=73657269616c, value=393135353032353731,
> timestamp=1290552297060000)
> (column=737461747573, value=5550, timestamp=1290552297060000)
> (column=74797065, value=486561727462656174,
> timestamp=1290552297060000))
>
> On Wed, Dec 1, 2010 at 2:25 PM, Aaron Morton <aa...@thelastpickle.com>wrote:
>
>> The Partitioner applies to the row keys, not the columns. Their order is
>> determined by the compare_with and compare_subcolumns_with CF settings
>>
>> So where you say "get the last 25 inserts for a key" I'm translating that
>> into "get the most recent 25 super columns for a row, where the super column
>> names are UUID's and the CF definition has compare_with: TimeUUIDType"
>>
>> You can send a get_slice where the SliceRange has count=25 and
>> reversed=True. If you know the 25th col name you can use it as the start
>> param, and AFAIK the operation would go faster Not sure how this translates
>> into calls against Pelops.
>>
>> This assumes you are using time / v1 UUID's that have an increasing
>> order.
>>
>> Hope that helps.
>>
>> Aaron
>>
>>
>>
>> On 02 Dec, 2010,at 09:19 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
>>
>> Is it possible to perform paginated queries using Random Partitioner in
>> 0.7 with Super Column Families whose Super Columns are UUID's? I don't
>> believe it is, based on this article:
>> http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner,
>> and my attempts with Pelops.
>>
>> Let's say I get the last 25 inserts for a key. I now know the 25th Super
>> Column UUID, and I want to start from there and get the next 25 inserts. Do
>> I have to change over to Order Preserving Partitioner? I'd like to avoid
>> this at all costs.
>>
>> Thanks,
>>
>> Frank
>>
>>
>
(Unknown)
Posted by Eric Evans <ee...@rackspace.com>.
On Wed, 2010-12-01 at 23:13 +0100, Moldován Eduárd wrote:
> unsubscribe
http://wiki.apache.org/cassandra/FAQ#unsubscribe
--
Eric Evans
eevans@rackspace.com
Re: Range Queries in RP on SCF in 0.7 with UUID SCs
Posted by Aaron Morton <aa...@thelastpickle.com>.
When you say "I want to get rows starting from a Super Column..." it's a bit confusing. Do you want to get super columns from a single row, or multiple rows? I'm assuming you are talking about getting columns from a single row / key as that's what your code does.
For the pelops code, it looks OK but I've not used Pelops. You can turn the logging up on the server and check the command that is sent to it. I'm would guess there is something wrong with the way you are transforming the start key.
For your cli example what was the command you executed ?
Aaron
On 02 Dec, 2010,at 11:03 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
Hey Aaron,
Yes, in regards to SCF definition, you are correct:
name: Sensor
column_type: Super
compare_with: TimeUUIDType
gc_grace_seconds: 864000
keys_cached: 10000.0
read_repair_chance: 1.0
rows_cached: 0.0
I'm not quite sure I follow you, though, as I think I'm doing what you specify. The Pelops code is below. Basically, I want to get rows starting from a Super Column with a specific UUID and limit the number, just as you inferred. When I run this code I just get the last N values (25 in this case) if non-reversed, and the first N values if reversed. However, regardless of what start param we use (Super Column UUID is String startKey below), we still get the same values for the specified amount (e.g. the same 25).
public void getSuperRowKeys(String rowKey, String columnFamily, int limit, String startKey) throws Exception {
byte[] byteArray = UuidHelper.timeUuidStringToBytes(startKey);
ByteBuffer bb = ByteBuffer.wrap(byteArray);
new UUID (bb.getLong(), bb.getLong());
List<SuperColumn> cols = selector.getPageOfSuperColumnsFromRow(columnFamily, rowKey, Bytes.fromByteBuffer(bb), false, limit, ConsistencyLevel.ONE);
for (SuperColumn col : cols) {
if (col.getName() != null) {
System.out.println("NAME: " + UUID.nameUUIDFromBytes(col.getName()));
for (Column c : col.columns) {
System.out.println("\t\tName: " + Bytes.toUTF8(c.getName())
+ " Value: " + Bytes.toUTF8(c.getValue())
+ " timestamp: " + c.timestamp);
}
}
}
}
Here is some example data from the CLI. If we specify 2f814d30-f758-11df-2f81-4d30f75811df as the start param (second super column down), we still get 52e6540-f759-11df-952e-6540f75911df (first super column) returned.
=> (super_column=952e6540-f759-11df-952e-6540f75911df,
(column=64617465, value=323031302d31312d32332032333a32393a30332e303030, timestamp=1290554997141000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290554997141000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554997141000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290554997141000)
(column=73657269616c, value=393135353032353731, timestamp=1290554997141000)
(column=737461747573, value=5550, timestamp=1290554997141000)
(column=74797065, value=486561727462656174, timestamp=1290554997141000))
=> (super_column=2f814d30-f758-11df-2f81-4d30f75811df,
(column=64617465, value=323031302d31312d32332032333a31393a30332e303030, timestamp=1290554397060000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290554397060000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554397060000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290554397060000)
(column=73657269616c, value=393135353032353731, timestamp=1290554397060000)
(column=737461747573, value=5550, timestamp=1290554397060000)
(column=74797065, value=486561727462656174, timestamp=1290554397060000))
=> (super_column=7c959f00-f757-11df-7c95-9f00f75711df,
(column=64617465, value=323031302d31312d32332032333a31343a30332e303030, timestamp=1290554096881000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290554096881000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554096881000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290554096881000)
(column=73657269616c, value=393135353032353731, timestamp=1290554096881000)
(column=737461747573, value=5550, timestamp=1290554096881000)
(column=74797065, value=486561727462656174, timestamp=1290554096881000))
=> (super_column=c9be6330-f756-11df-c9be-6330f75611df,
(column=64617465, value=323031302d31312d32332032333a30393a30332e303030, timestamp=1290553796836000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290553796836000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553796836000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290553796836000)
(column=73657269616c, value=393135353032353731, timestamp=1290553796836000)
(column=737461747573, value=5550, timestamp=1290553796836000)
(column=74797065, value=486561727462656174, timestamp=1290553796836000))
=> (super_column=17108150-f756-11df-1710-8150f75611df,
(column=64617465, value=323031302d31312d32332032333a30343a30332e303030, timestamp=1290553497067000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290553497067000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553497067000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290553497067000)
(column=73657269616c, value=393135353032353731, timestamp=1290553497067000)
(column=737461747573, value=5550, timestamp=1290553497067000)
(column=74797065, value=486561727462656174, timestamp=1290553497067000))
=> (super_column=641da730-f755-11df-641d-a730f75511df,
(column=64617465, value=323031302d31312d32332032323a35393a30332e303030, timestamp=1290553196836000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290553196836000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553196836000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290553196836000)
(column=73657269616c, value=393135353032353731, timestamp=1290553196836000)
(column=737461747573, value=5550, timestamp=1290553196836000)
(column=74797065, value=486561727462656174, timestamp=1290553196836000))
=> (super_column=4bce9420-f753-11df-4bce-9420f75311df,
(column=64617465, value=323031302d31312d32332032323a34343a30332e303030, timestamp=1290552297060000)
(column=65787472615f696e666f, value=6e6f6e65, timestamp=1290552297060000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290552297060000)
(column=7365636f6e64735f746f5f6e657874, value=373530, timestamp=1290552297060000)
(column=73657269616c, value=393135353032353731, timestamp=1290552297060000)
(column=737461747573, value=5550, timestamp=1290552297060000)
(column=74797065, value=486561727462656174, timestamp=1290552297060000))
On Wed, Dec 1, 2010 at 2:25 PM, Aaron Morton <aa...@thelastpickle.com> wrote:
The Partitioner applies to the row keys, not the columns. Their order is determined by the compare_with and compare_subcolumns_with CF settings
So where you say "get the last 25 inserts for a key" I'm translating that into "get the most recent 25 super columns for a row, where the super column names are UUID's and the CF definition has compare_with: TimeUUIDType"
You can send a get_slice where the SliceRange has count=25 and reversed=True. If you know the 25th col name you can use it as the start param, and AFAIK the operation would go faster. Not sure how this translates into calls against Pelops.
This assumes you are using time / v1 UUID's that have an increasing order.
Hope that helps.
Aaron
On 02 Dec, 2010,at 09:19 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
Is it possible to perform paginated queries using Random Partitioner in 0.7 with Super Column Families whose Super Columns are UUID's? I don't believe it is, based on this article: http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner, and my attempts with Pelops.
Let's say I get the last 25 inserts for a key. I now know the 25th Super Column UUID, and I want to start from there and get the next 25 inserts. Do I have to change over to Order Preserving Partitioner? I'd like to avoid this at all costs.
Thanks,
Frank
Re: Range Queries in RP on SCF in 0.7 with UUID SCs
Posted by Frank LoVecchio <fr...@isidorey.com>.
Hey Aaron,
Yes, in regards to SCF definition, you are correct:
name: Sensor
column_type: Super
compare_with: TimeUUIDType
gc_grace_seconds: 864000
keys_cached: 10000.0
read_repair_chance: 1.0
rows_cached: 0.0
I'm not quite sure I follow you, though, as I think I'm doing what you
specify. The Pelops code is below. Basically, I want to get rows starting
from a Super Column with a specific UUID and limit the number, just as you
inferred. When I run this code I just get the last N values (25 in this
case) if non-reversed, and the first N values if reversed. However,
regardless of what start param we use (Super Column UUID is String startKey
below), we still get the same values for the specified amount (e.g. the same
25).
*public* *void* getSuperRowKeys(String rowKey, String columnFamily,
*int* limit,
String startKey) *throws* Exception {
*byte*[] byteArray = UuidHelper.*timeUuidStringToBytes*(startKey);
ByteBuffer bb = ByteBuffer.*wrap*(byteArray);
*new* UUID (bb.getLong(), bb.getLong());
List<SuperColumn> cols = selector.getPageOfSuperColumnsFromRow(columnFamily,
rowKey, Bytes.*fromByteBuffer*(bb), *false*, limit, ConsistencyLevel.*ONE*);
*for* (SuperColumn col : cols) {
*if* (col.getName() != *null*) {
System.*out*.println("NAME: " + UUID.*nameUUIDFromBytes*(col.getName()));
*for* (Column c : col.columns) {
System.*out*.println("\t\tName: " + Bytes.*toUTF8*(c.getName())
+ " Value: " + Bytes.*toUTF8*(c.getValue())
+ " timestamp: " + c.timestamp);
}
}
}
}
Here is some example data from the CLI. If we specify
2f814d30-f758-11df-2f81-4d30f75811df
as the start param (second super column down), we still get
52e6540-f759-11df-952e-6540f75911df
(first super column) returned.
=> (super_column=952e6540-f759-11df-952e-6540f75911df,
(column=64617465, value=323031302d31312d32332032333a32393a30332e303030,
timestamp=1290554997141000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290554997141000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554997141000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290554997141000)
(column=73657269616c, value=393135353032353731,
timestamp=1290554997141000)
(column=737461747573, value=5550, timestamp=1290554997141000)
(column=74797065, value=486561727462656174,
timestamp=1290554997141000))
=> (super_column=2f814d30-f758-11df-2f81-4d30f75811df,
(column=64617465, value=323031302d31312d32332032333a31393a30332e303030,
timestamp=1290554397060000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290554397060000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554397060000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290554397060000)
(column=73657269616c, value=393135353032353731,
timestamp=1290554397060000)
(column=737461747573, value=5550, timestamp=1290554397060000)
(column=74797065, value=486561727462656174,
timestamp=1290554397060000))
=> (super_column=7c959f00-f757-11df-7c95-9f00f75711df,
(column=64617465, value=323031302d31312d32332032333a31343a30332e303030,
timestamp=1290554096881000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290554096881000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290554096881000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290554096881000)
(column=73657269616c, value=393135353032353731,
timestamp=1290554096881000)
(column=737461747573, value=5550, timestamp=1290554096881000)
(column=74797065, value=486561727462656174,
timestamp=1290554096881000))
=> (super_column=c9be6330-f756-11df-c9be-6330f75611df,
(column=64617465, value=323031302d31312d32332032333a30393a30332e303030,
timestamp=1290553796836000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290553796836000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553796836000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290553796836000)
(column=73657269616c, value=393135353032353731,
timestamp=1290553796836000)
(column=737461747573, value=5550, timestamp=1290553796836000)
(column=74797065, value=486561727462656174,
timestamp=1290553796836000))
=> (super_column=17108150-f756-11df-1710-8150f75611df,
(column=64617465, value=323031302d31312d32332032333a30343a30332e303030,
timestamp=1290553497067000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290553497067000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553497067000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290553497067000)
(column=73657269616c, value=393135353032353731,
timestamp=1290553497067000)
(column=737461747573, value=5550, timestamp=1290553497067000)
(column=74797065, value=486561727462656174,
timestamp=1290553497067000))
=> (super_column=641da730-f755-11df-641d-a730f75511df,
(column=64617465, value=323031302d31312d32332032323a35393a30332e303030,
timestamp=1290553196836000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290553196836000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290553196836000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290553196836000)
(column=73657269616c, value=393135353032353731,
timestamp=1290553196836000)
(column=737461747573, value=5550, timestamp=1290553196836000)
(column=74797065, value=486561727462656174,
timestamp=1290553196836000))
=> (super_column=4bce9420-f753-11df-4bce-9420f75311df,
(column=64617465, value=323031302d31312d32332032323a34343a30332e303030,
timestamp=1290552297060000)
(column=65787472615f696e666f, value=6e6f6e65,
timestamp=1290552297060000)
(column=726561736f6e, value=6e6f6e65, timestamp=1290552297060000)
(column=7365636f6e64735f746f5f6e657874, value=373530,
timestamp=1290552297060000)
(column=73657269616c, value=393135353032353731,
timestamp=1290552297060000)
(column=737461747573, value=5550, timestamp=1290552297060000)
(column=74797065, value=486561727462656174,
timestamp=1290552297060000))
On Wed, Dec 1, 2010 at 2:25 PM, Aaron Morton <aa...@thelastpickle.com>wrote:
> The Partitioner applies to the row keys, not the columns. Their order is
> determined by the compare_with and compare_subcolumns_with CF settings
>
> So where you say "get the last 25 inserts for a key" I'm translating that
> into "get the most recent 25 super columns for a row, where the super column
> names are UUID's and the CF definition has compare_with: TimeUUIDType"
>
> You can send a get_slice where the SliceRange has count=25 and
> reversed=True. If you know the 25th col name you can use it as the start
> param, and AFAIK the operation would go faster. Not sure how this translates
> into calls against Pelops.
>
> This assumes you are using time / v1 UUID's that have an increasing order.
>
> Hope that helps.
>
> Aaron
>
>
> On 02 Dec, 2010,at 09:19 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
>
> Is it possible to perform paginated queries using Random Partitioner in 0.7
> with Super Column Families whose Super Columns are UUID's? I don't believe
> it is, based on this article:
> http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner,
> and my attempts with Pelops.
>
> Let's say I get the last 25 inserts for a key. I now know the 25th Super
> Column UUID, and I want to start from there and get the next 25 inserts. Do
> I have to change over to Order Preserving Partitioner? I'd like to avoid
> this at all costs.
>
> Thanks,
>
> Frank
>
>
Re: Range Queries in RP on SCF in 0.7 with UUID SCs
Posted by Aaron Morton <aa...@thelastpickle.com>.
The Partitioner applies to the row keys, not the columns. Their order is determined by the compare_with and compare_subcolumns_with CF settings.
So where you say "get the last 25 inserts for a key" I'm translating that into "get the most recent 25 super columns for a row, where the super column names are UUID's and the CF definition has compare_with: TimeUUIDType"
You can send a get_slice where the SliceRange has count=25 and reversed=True. If you know the 25th col name you can use it as the start param, and AFAIK the operation would go faster. Not sure how this translates into calls against Pelops.
This assumes you are using time / v1 UUID's that have an increasing order.
Hope that helps.
Aaron
On 02 Dec, 2010,at 09:19 AM, Frank LoVecchio <fr...@isidorey.com> wrote:
Is it possible to perform paginated queries using Random Partitioner in 0.7 with Super Column Families whose Super Columns are UUID's? I don't believe it is, based on this article: http://ria101.wordpress.com/2010/02/22/cassandra-randompartitioner-vs-orderpreservingpartitioner, and my attempts with Pelops.
Let's say I get the last 25 inserts for a key. I now know the 25th Super Column UUID, and I want to start from there and get the next 25 inserts. Do I have to change over to Order Preserving Partitioner? I'd like to avoid this at all costs.
Thanks,
Frank