Hi,
I have an hbase cluster where I have a table with a composite key. I map this
table to a Hive external table using which I insert/select data into/from this
table:
CREATE EXTERNAL TABLE event(key
struct<name:string,dateCreated:string,uid:string>, {more columns here})
ROW FORMAT DELIMITED
COLLECTION ITEMS TERMINATED BY '~'
STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
WITH SERDEPROPERTIES ("hbase.columns.mapping" = ":key, other columns ")
TBLPROPERTIES ("hbase.table.name" = "event");
The table has about 10 million rows. When I do a select * using all 3
components of the key, essentially selecting just 1 row, the response time is
almost 700 sec, which seems pretty bad.
For comparison purpose, I created another table with a simple string key, and
the rest of the columns etc same. The key is a string UUID. Table has same
number of column families and same number of rows.
CREATE EXTERNAL TABLE test_event(key string, blah blah.....
TBLPROPERTIES ("hbase.table.name" = "test_event");
When I select a single row from this table by doing select * where
key='something', the response time is 35 sec.
This seems to indicate that in case of composite keys, there is a full table
scan happening. This seems weird.
What am I missing here? Is there something special I need to do to get good
read performance if I am using composite keys ?
Insert performance in both cases is comparable and is as per expectation.
Any help is appreciated.
Here is the env spec:
Amazon EMR
Hbase Cluster- 3 core nodes with 7.5 GB RAM each, 2 CPUs of 2.2 GHz each.
Master 7.5 GB RAM, 2 CPUs of 2.2 GHz each
Hive Cluster - 3 core nodes 3.75 GB RAM each, 1 CPU of 1.8 GHz. Master 3.75 GB
RAM, 1 CPU of 1.8 GHz
Thanks
Rupinder
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