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Gunakan Parket SerDe untuk membuat tabel Athena dari data Parket.
Parket SerDe digunakan untuk data yang disimpan dalam format Parket
Nama pustaka serialisasi
Nama perpustakaan serialisasi untuk Parket SerDe adalah. org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe Untuk informasi kode sumber, lihat Kelas ParquetHiveSerDe
catatan
Ganti myregion s3://athena-examples- dengan pengenal wilayah tempat Anda menjalankan Athena, misalnya,. myregion/path/to/data/s3://athena-examples-us-west-1/path/to/data/
Gunakan CREATE TABLE pernyataan berikut untuk membuat tabel Athena dari data dasar yang disimpan dalam format Parket di 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");Jalankan MSCK REPAIR TABLE pernyataan di atas meja untuk menyegarkan metadata partisi:
MSCK REPAIR TABLE flight_delays_pq;Kueri 10 rute teratas yang tertunda lebih dari 1 jam:
SELECT origin, dest, count(*) as delays
FROM flight_delays_pq
WHERE depdelayminutes > 60
GROUP BY origin, dest
ORDER BY 3 DESC
LIMIT 10;catatan
Data tabel penerbangan berasal dari Penerbangan
Abaikan statistik Parket
Ketika Anda membaca data Parket, Anda mungkin menerima pesan kesalahan seperti berikut:
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.
Untuk mengatasi masalah ini, gunakan ALTER TABLE SET
TBLPROPERTIES pernyataan CREATE TABLE or untuk menyetel SerDe parquet.ignore.statistics properti Parkettrue, seperti pada contoh berikut.
CREATE TABLE contoh
...
ROW FORMAT SERDE
'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe'
WITH SERDEPROPERTIES (
'parquet.ignore.statistics'='true')
STORED AS PARQUET
...
Contoh ALTER TABLE
ALTER TABLE ... SET TBLPROPERTIES ('parquet.ignore.statistics'='true')