Parquet SerDe

SerDe name

ParquetHiveSerDe is used for data stored in Parquet format.

Note

To convert data into Parquet format, you can use CREATE TABLE AS SELECT (CTAS) queries. For more information, see Creating a table from query results (CTAS), Examples of CTAS queries and Using CTAS and INSERT INTO for ETL and data analysis.

Library name

Athena uses the following class when it needs to deserialize data stored in Parquet: org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe

Example: Querying a file stored in parquet

Note

Replace myregion in s3://athena-examples-myregion/path/to/data/ with the region identifier where you run Athena, for example, s3://athena-examples-us-west-1/path/to/data/.

Use the following CREATE TABLE statement to create an Athena table from the underlying data stored in Parquet format in Amazon S3:

CREATE EXTERNAL TABLE flight_delays_pq (
    yr INT,
    quarter INT,
    month INT,
    dayofmonth INT,
    dayofweek INT,
    flightdate STRING,
    uniquecarrier STRING,
    airlineid INT,
    carrier STRING,
    tailnum STRING,
    flightnum STRING,
    originairportid INT,
    originairportseqid INT,
    origincitymarketid INT,
    origin STRING,
    origincityname STRING,
    originstate STRING,
    originstatefips STRING,
    originstatename STRING,
    originwac INT,
    destairportid INT,
    destairportseqid INT,
    destcitymarketid INT,
    dest STRING,
    destcityname STRING,
    deststate STRING,
    deststatefips STRING,
    deststatename STRING,
    destwac INT,
    crsdeptime STRING,
    deptime STRING,
    depdelay INT,
    depdelayminutes INT,
    depdel15 INT,
    departuredelaygroups INT,
    deptimeblk STRING,
    taxiout INT,
    wheelsoff STRING,
    wheelson STRING,
    taxiin INT,
    crsarrtime INT,
    arrtime STRING,
    arrdelay INT,
    arrdelayminutes INT,
    arrdel15 INT,
    arrivaldelaygroups INT,
    arrtimeblk STRING,
    cancelled INT,
    cancellationcode STRING,
    diverted INT,
    crselapsedtime INT,
    actualelapsedtime INT,
    airtime INT,
    flights INT,
    distance INT,
    distancegroup INT,
    carrierdelay INT,
    weatherdelay INT,
    nasdelay INT,
    securitydelay INT,
    lateaircraftdelay INT,
    firstdeptime STRING,
    totaladdgtime INT,
    longestaddgtime INT,
    divairportlandings INT,
    divreacheddest INT,
    divactualelapsedtime INT,
    divarrdelay INT,
    divdistance INT,
    div1airport STRING,
    div1airportid INT,
    div1airportseqid INT,
    div1wheelson STRING,
    div1totalgtime INT,
    div1longestgtime INT,
    div1wheelsoff STRING,
    div1tailnum STRING,
    div2airport STRING,
    div2airportid INT,
    div2airportseqid INT,
    div2wheelson STRING,
    div2totalgtime INT,
    div2longestgtime INT,
    div2wheelsoff STRING,
    div2tailnum STRING,
    div3airport STRING,
    div3airportid INT,
    div3airportseqid INT,
    div3wheelson STRING,
    div3totalgtime INT,
    div3longestgtime INT,
    div3wheelsoff STRING,
    div3tailnum STRING,
    div4airport STRING,
    div4airportid INT,
    div4airportseqid INT,
    div4wheelson STRING,
    div4totalgtime INT,
    div4longestgtime INT,
    div4wheelsoff STRING,
    div4tailnum STRING,
    div5airport STRING,
    div5airportid INT,
    div5airportseqid INT,
    div5wheelson STRING,
    div5totalgtime INT,
    div5longestgtime INT,
    div5wheelsoff STRING,
    div5tailnum STRING
)
PARTITIONED BY (year STRING)
STORED AS PARQUET
LOCATION 's3://athena-examples-myregion/flight/parquet/'
tblproperties ("parquet.compression"="SNAPPY");

Run the MSCK REPAIR TABLE statement on the table to refresh partition metadata:

MSCK REPAIR TABLE flight_delays_pq;

Query the top 10 routes delayed by more than 1 hour:

SELECT origin, dest, count(*) as delays
FROM flight_delays_pq
WHERE depdelayminutes > 60
GROUP BY origin, dest
ORDER BY 3 DESC
LIMIT 10;

Note

The flight table data comes from Flights provided by US Department of Transportation, Bureau of Transportation Statistics. Desaturated from original.

Ignoring Parquet statistics

When you read Parquet data, you might receive error messages like the following:

HIVE_CANNOT_OPEN_SPLIT: Index x out of bounds for length y
HIVE_CURSOR_ERROR: Failed to read x bytes
HIVE_CURSOR_ERROR: FailureException at Malformed input: offset=x
HIVE_CURSOR_ERROR: FailureException at java.io.IOException: 
can not read class org.apache.parquet.format.PageHeader: Socket is closed by peer.

To workaround this issue, use the CREATE TABLE or ALTER TABLE SET TBLPROPERTIES statement to set the Parquet SerDe parquet.ignore.statistics property to true, as in the following examples.

CREATE TABLE example

...
ROW FORMAT SERDE  
'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe' 
WITH SERDEPROPERTIES (  
'parquet.ignore.statistics'='true')  
STORED AS PARQUET 
...

ALTER TABLE example

ALTER TABLE ... SET TBLPROPERTIES ('parquet.ignore.statistics'='true')