Trying to cache a table which has its data in s3 results in an IllegalArgumentException

Query: show create table functional.alltypestiny
"CREATE EXTERNAL TABLE functional.alltypestiny (
  id INT, 
  bool_col BOOLEAN, 
  tinyint_col TINYINT, 
  smallint_col SMALLINT, 
  int_col INT, 
  bigint_col BIGINT, 
  float_col FLOAT, 
  double_col DOUBLE, 
  date_string_col STRING, 
  string_col STRING, 
  timestamp_col TIMESTAMP
)
PARTITIONED BY (
  year INT, 
  month INT
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' ESCAPED BY '\\'
WITH SERDEPROPERTIES ('field.delim'=',', 'serialization.format'=',', 'escape.delim'='\\')
STORED AS TEXTFILE
LOCATION 's3a://<s3_bucket>/test-warehouse/alltypestiny'
TBLPROPERTIES ('STATS_GENERATED_VIA_STATS_TASK'='true', 'transient_lastDdlTime'='1422275382', 'numRows'='8')"
Fetched 1 row(s) in 0.01s

[ishaan-impala-ec2.vpc.cloudera.com:21000] > alter table functional.alltypestiny set cached in "testPool";
Query: alter table functional.alltypestiny set cached in "testPool"
ERROR: IllegalArgumentException: Wrong FS: s3a://<s3_bucket>/test-warehouse/alltypestiny, expected: hdfs://localhost:20500