Database Reference
In-Depth Information
HDFS, space limitation, memory swapping, or latency could impact the Impala exe-
cution. Any of these issues could introduce instability in HDFS or impact the whole
cluster, depending on how serious the problem is. In this situation, you would need
to work with your Hadoop administrator to resolve these problems and get Impala up
and running.
Input file format-specific issues
Impala can load and query various kinds of datafiles stored on Hadoop. Sometimes
you may receive an error while reading these datafiles or failed query requests. Most
probably it is because either the file format is not supported, or Impala is limited
to only queries and cannot process
CREATE
or
INSERT
requests. In the following
table, you can see which file formats are supported and whether Impala can read
and query those files:
Is CREATE and
INSERT suppor-
ted
Compression
type
Is the query
supported?
File type
Format type
Text
Unstructured LZO
Yes
Yes
Avro
Structured
Snappy, GZIP,
deflate, BZIP2
No
Query only (use
Hive to load file)
RCFile
Structured
Snappy, GZIP,
deflate, BZIP2
CREATE
: Yes
Query only (use
Hive to load file)
INSERT
: No
SequenceFile Structured
Snappy, GZIP,
deflate, BZIP2
CREATE
: Yes
Query only (use
Hive to load file)
INSERT
: No
