Hi:
We are currently using Cassandra 0.8.10 and have run into some strange issues
surrounding
querying for a range of data
I ran a couple of get statements via the Cassandra client and found some
interesting results:
Consider the following Column Family Definition:
ColumnFamily: events
Key Validation Class: org.apache.cassandra.db.marshal.BytesType
Default column value validator: org.apache.cassandra.db.marshal.BytesType
Columns sorted by: org.apache.cassandra.db.marshal.UTF8Type
Row cache size / save period in seconds: 0.0/0
Row Cache Provider:
org.apache.cassandra.cache.ConcurrentLinkedHashCacheProvider
Key cache size / save period in seconds: 200000.0/14400
Memtable thresholds: 0.2953125/1440/63 (millions of ops/minutes/MB)
GC grace seconds: 864000
Compaction min/max thresholds: 4/32
Read repair chance: 1.0
Replicate on write: true
Built indexes: [events.events_Firm_idx, events.events_OrdType_idx,
events.events_OrderID_idx
, events.events_OrderQty_idx, events.events_Price_idx,
events.events_Symbol_idx, events.events_ds_timestamp_idx]
Column Metadata:
Column Name: Firm
Validation Class: org.apache.cassandra.db.marshal.BytesType
Index Name: events_Firm_idx
Index Type: KEYS
Column Name: OrdType
Validation Class: org.apache.cassandra.db.marshal.BytesType
Index Name: events_OrdType_idx
Index Type: KEYS
Column Name: OrderID
Validation Class: org.apache.cassandra.db.marshal.BytesType
Index Name: events_OrderID_idx
Index Type: KEYS
Column Name: OrderQty
Validation Class: org.apache.cassandra.db.marshal.LongType
Index Name: events_OrderQty_idx
Index Type: KEYS
Column Name: Price
Validation Class: org.apache.cassandra.db.marshal.LongType
Index Name: events_Price_idx
Index Type: KEYS
Column Name: Symbol
Validation Class: org.apache.cassandra.db.marshal.BytesType
Index Name: events_Symbol_idx
Column Name: ds_timestamp
Validation Class: org.apache.cassandra.db.marshal.LongType
Index Name: events_ds_timestamp_idx
Index Type: KEYS
get events WHERE Firm=434550 AND ds_timestamp=1341955958200;
…and the results are pretty much instantaneous.
1 Row Returned.
[default@FIX] get events WHERE Firm=434550 AND ds_timestamp=1341955958200;
-------------------
RowKey: 64326430363362302d636164362d313165312d626637622d333836303737306639303133
=> (column=ClOrdID, value=32323833, timestamp=1341955980651010)
=> (column=Firm, value=434550, timestamp=1341955980651026)
=> (column=OrdType, value=31, timestamp=1341955980651008)
=> (column=OrderQty, value=8200, timestamp=1341955980651013)
=> (column=Price, value=433561, timestamp=1341955980651019)
=> (column=Symbol, value=544e54, timestamp=1341955980651018)
=> (column=ds_timestamp, value=1341955958200, timestamp=1341955980651020)
If I run the following query:
get events WHERE Firm=434550 AND ds_timestamp>=1341955958200 AND
ds_timestamp<=1341955958200;
(which in theory would should return the same 1 row result)
It runs for around 12 seconds,
And I get:
TimedOutException()
If I run:
get events WHERE Firm=434550 AND ds_timestamp>=1341955958200;
or
get events WHERE Firm=434550 AND ds_timestamp<=1341955958200;
The results return quickly.
Curious, I also ran a similar set of queries against the price field:
get events WHERE Firm=434550 AND Price=433561;
get events WHERE Firm=434550 AND Price>=433561;
get events WHERE Firm=434550 AND Price<=433561;
These all work fine.
While,
get events WHERE Firm=434550 AND Price=433561 AND Price <= 433561;
returns an IO Exception.
This feels like it’s attempting to do a full table scan here….
What is going on here?
Am I doing something incorrectly?
We also see similar behavior when submit the query through our app via the
Thrift API.
Thanks,
JohnB
