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https://issues.apache.org/jira/browse/HIVE-14789?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mithun Radhakrishnan reassigned HIVE-14789:
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Assignee: Mithun Radhakrishnan
> Avro Table-reads bork when using SerDe-generated table-schema.
> --------------------------------------------------------------
>
> Key: HIVE-14789
> URL: https://issues.apache.org/jira/browse/HIVE-14789
> Project: Hive
> Issue Type: Bug
> Components: Serializers/Deserializers
> Affects Versions: 1.2.1, 2.0.1
> Reporter: Mithun Radhakrishnan
> Assignee: Mithun Radhakrishnan
>
> AvroSerDe allows one to skip the table-columns in a table-definition when
> creating a table, as long as the TBLPROPERTIES includes a valid
> {{avro.schema.url}} or {{avro.schema.literal}}. The table-columns are
> inferred from processing the Avro schema file/literal.
> The problem is that the inferred schema might not be congruent with the
> actual schema in the Avro schema file/literal. Consider the following table
> definition:
> {code:sql}
> CREATE TABLE avro_schema_break_1
> ROW FORMAT
> SERDE 'org.apache.hadoop.hive.serde2.avro.AvroSerDe'
> STORED AS
> INPUTFORMAT 'org.apache.hadoop.hive.ql.io.avro.AvroContainerInputFormat'
> OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.avro.AvroContainerOutputFormat'
> TBLPROPERTIES ('avro.schema.literal'='{
> "type": "record",
> "name": "Messages",
> "namespace": "net.myth",
> "fields": [
> {
> "name": "header",
> "type": [
> "null",
> {
> "type": "record",
> "name": "HeaderInfo",
> "fields": [
> {
> "name": "inferred_event_type",
> "type": [
> "null",
> "string"
> ],
> "default": null
> },
> {
> "name": "event_type",
> "type": [
> "null",
> "string"
> ],
> "default": null
> },
> {
> "name": "event_version",
> "type": [
> "null",
> "string"
> ],
> "default": null
> }
> ]
> }
> ]
> },
> {
> "name": "messages",
> "type": {
> "type": "array",
> "items": {
> "name": "MessageInfo",
> "type": "record",
> "fields": [
> {
> "name": "message_id",
> "type": [
> "null",
> "string"
> ],
> "doc": "Message-ID"
> },
> {
> "name": "received_date",
> "type": [
> "null",
> "long"
> ],
> "doc": "Received Date"
> },
> {
> "name": "sent_date",
> "type": [
> "null",
> "long"
> ]
> },
> {
> "name": "from_name",
> "type": [
> "null",
> "string"
> ]
> },
> {
> "name": "flags",
> "type": [
> "null",
> {
> "type": "record",
> "name": "Flags",
> "fields": [
> {
> "name": "is_seen",
> "type": [
> "null",
> "boolean"
> ],
> "default": null
> },
> {
> "name": "is_read",
> "type": [
> "null",
> "boolean"
> ],
> "default": null
> },
> {
> "name": "is_flagged",
> "type": [
> "null",
> "boolean"
> ],
> "default": null
> }
> ]
> }
> ],
> "default": null
> }
> ]
> }
> }
> }
> ]
> }');
> {code}
> This produces a table with the following schema:
> {noformat}
> 2016-09-19T13:23:42,934 DEBUG [0ce7e586-13ea-4390-ac2a-6dac36e8a216 main]
> hive.log: DDL: struct avro_schema_break_1 {
> struct<inferred_event_type:string,event_type:string,event_version:string>
> header,
> list<struct<message_id:string,received_date:i64,sent_date:i64,from_name:string,flags:struct<is_seen:bool,is_read:bool,is_flagged:bool>>>
> messages}
> {noformat}
> Data written to this table using the AvroSchema from {{avro.schema.literal}}
> using Pig's {{AvroStorage}} cannot be read using Hive using the generated
> table schema. This is the exception one sees:
> {noformat}
> java.io.IOException: org.apache.avro.AvroTypeException: Found
> net.myth.HeaderInfo, expecting union
> at
> org.apache.hadoop.hive.ql.exec.FetchOperator.getNextRow(FetchOperator.java:521)
> at
> org.apache.hadoop.hive.ql.exec.FetchOperator.pushRow(FetchOperator.java:428)
> at org.apache.hadoop.hive.ql.exec.FetchTask.fetch(FetchTask.java:147)
> at org.apache.hadoop.hive.ql.Driver.getResults(Driver.java:2019)
> at org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:253)
> at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:184)
> at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:400)
> at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:336)
> at
> org.apache.hadoop.hive.ql.QTestUtil.executeClientInternal(QTestUtil.java:1162)
> at org.apache.hadoop.hive.ql.QTestUtil.executeClient(QTestUtil.java:1136)
> at
> org.apache.hadoop.hive.cli.control.CoreCliDriver.runTest(CoreCliDriver.java:172)
> at
> org.apache.hadoop.hive.cli.control.CliAdapter.runTest(CliAdapter.java:104)
> at
> org.apache.hadoop.hive.cli.TestCliDriver.testCliDriver(TestCliDriver.java:59)
> ...
> {noformat}
> The only way to read this table is by using the attached
> {{avro.schema.literal}} or {{avro.schema.url}}. This has implications on
> systems where data could be produced externally to Hive. It also has
> repercussions on table-replication using Falcon/GDM, in that the schema
> file/literal needs to be replicated.
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