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https://issues.apache.org/jira/browse/SQOOP-1804?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14257749#comment-14257749
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Gwen Shapira commented on SQOOP-1804:
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Had a quick chat with [~vybs].
We agree that last_value is the minimum needed.
However, if we can support a bit more connector state without huge effort, it
is not a bad idea. Even though we don't know exactly how connectors will use it.
The idea is to have a "state" per connector per submission, just like the
connectors have configs per job.
I recommended matching the schema to what we have in Configs:
I.e. - do not allow the connector to store whatever key-values they want per
submission, but rather force them to declare list of state keys (similar to
configs) in advance, and fill them out per submission. This way it will be easy
to enforce consistency, get a list of values per key, display something
reasonable to users, etc.
Also, for the record: if this turns out to be overly complicated, we can always
fall back to storing just last_value as a long. (i.e. it will be nice to
support more, but not an absolute requirement right now).
> Repository Structure + API: Storing/Retrieving the From/To state of the
> incremental read/ write
> -----------------------------------------------------------------------------------------------
>
> Key: SQOOP-1804
> URL: https://issues.apache.org/jira/browse/SQOOP-1804
> Project: Sqoop
> Issue Type: Sub-task
> Reporter: Veena Basavaraj
> Assignee: Veena Basavaraj
> Fix For: 1.99.5
>
>
> Details of this proposal are in the wiki.
> https://cwiki.apache.org/confluence/display/SQOOP/Delta+Fetch+And+Merge+Design#DeltaFetchAndMergeDesign-Wheretostoretheoutputinsqoop?
> Update: The above highlights the pros and cons of each approach.
> #4 is chosen, since it is less intrusive, more clean and allows U/Edit per
> value in the output easily.
> Will use this ticket for more detailed discussion on storage options for the
> output from connectors
> 1.
> {code}
> // will have FK to submission
> public static final String QUERY_CREATE_TABLE_SQ_JOB_OUTPUT_SUBMISSION =
> "CREATE TABLE " + TABLE_SQ_JOB_OUTPUT + " ("
> + COLUMN_SQ_JOB_OUT_ID + " BIGINT GENERATED ALWAYS AS IDENTITY (START
> WITH 1, INCREMENT BY 1), "
> + COLUMN_SQ_JOB_OUT_KEY + " VARCHAR(32), "
> + COLUMN_SQ_JOB_OUT_VALUE + " LONG VARCHAR,"
> + COLUMN_SQ_JOB_OUT_TYPE + " VARCHAR(32),"
> + COLUMN_SQD_ID + " VARCHAR(32)," // FK to the direction table, since
> this allows to distinguish output from FROM/ TO part of the job
> + COLUMN_SQRS_SUBMISSION + " BIGINT, "
> + "CONSTRAINT " + CONSTRAINT_SQRS_SQS + " "
> + "FOREIGN KEY (" + COLUMN_SQRS_SUBMISSION + ") "
> + "REFERENCES " + TABLE_SQ_SUBMISSION + "(" + COLUMN_SQS_ID + ") ON
> DELETE CASCADE "
> {code}
> 2.
> At the code level, we will define MOutputType, one of the types can be BLOB
> as well, if a connector decides to store the value as a BLOB
> {code}
> class JobOutput {
> String key;
> Object value;
> MOutputType type;
> }
> {code}
> 3.
> At the repository API, add a new API to get job output for a particular
> submission Id and allow updates on values.
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