When use alluxio as hive fs,cant get data from alluxio.

[awkwardd]

Trino version:461 alluxio version:2.9.5
Follow the alluxio tutorial(https://docs.alluxio.io/os/user/stable/en/compute/Trino.html) to create a hive table and save it on alluxio. After adding the fs.alluxio.enabled configuration to the hive catalog, accessing the table can only return metadata but no actual data and there is no error report. Debug the program and find that the AlluxioFileSystem list method do get the file list alluxio:/.Why this happen?Is there anything wrong with my operation or configuration?

[awkwardd]

@JiamingMai Could you help me plz.

[awkwardd]

yes
[hadoop@alluxiomaster alluxio]$ bin/alluxio fs ls /
drwxr-xr-x hadoop hadoop 0 PERSISTED 10-10-2024 22:50:44:867 DIR /.alluxio_ufs_persistencedrwxr-xr-x hadoop supergroup 0 PERSISTED 10-09-2024 02:26:22:158 DIR /alluxio_backups
drwxr-xr-x hadoop supergroup 0 PERSISTED 07-03-2024 23:51:01:515 DIR /data
drwxr-xr-x hadoop hadoop 0 PERSISTED 10-09-2024 23:13:47:481 DIR /default_tests_files
drwxr-xr-x hadoop hadoop 1 PERSISTED 10-10-2024 22:50:44:867 DIR /ml-100k
drwx-wx-wx hadoop supergroup 0 PERSISTED 07-03-2024 23:50:51:385 DIR /tmp
drwxr-xr-x hadoop supergroup 2 PERSISTED 09-02-2024 02:43:44:636 DIR /user

[JiamingMai]

This indicates that Alluxio 2.9.5 can access the underlying file system. Can you share your DDL SQL of the Hive table? So that we will have a test in our environment.

[awkwardd]

CREATE TABLE u_user(
userid int,
age int,
gender char(1),
occupation string,
zipcode string)
ROW FORMAT SERDE
'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe'
WITH SERDEPROPERTIES (
'field.delim'='|',
'serialization.format'='|')
STORED AS INPUTFORMAT
'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
'alluxio://192.168.88.112:19998/ml-100k'; just as the tutorial say.

[JiamingMai]

Thanks. We will have a try.

[awkwardd]

Thank you for help me.This has been confusing me for days.

[awkwardd]

I find that when use alluxio as fs, the MetaDataManger getTableStatistics() can't return the row count for the query.Is that the reason why the query can't get any data from alluxio?

[JiamingMai]

Can you try calling sync_partition_metadata and submit the query again?

[awkwardd]

It doesn't work.

[awkwardd]

I solved this problem by modify the AlluxioFileIterator.java https://github.com/trinodb/trino/pull/23815/commits @JiamingMai .You can take a look.

[JiamingMai]

Thanks a lot. We will take a look later.