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Posted to issues@hbase.apache.org by "Andrew Kyle Purtell (Jira)" <ji...@apache.org> on 2020/01/10 19:23:00 UTC

[jira] [Updated] (HBASE-23678) Literate builder API for version management in schema

     [ https://issues.apache.org/jira/browse/HBASE-23678?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Kyle Purtell updated HBASE-23678:
----------------------------------------
    Description: 
Lars designed the combination of VERSIONS, TTL, MIN_VERSIONS, and KEEP_DELETED_CELLS with a maximum of flexibility. There is a lot of nuance regarding their usage. Almost all combinations of these four settings make sense for some use cases (exceptions are MIN_VERSIONS > 0 without TTL, and KEEP_DELETED_CELLS=TTL without TTL). There should be a way to make the behavior with TTL easier to conceive when creating the schema. This could take the form of a literate builder API for ColumnDescriptor or an extension to an existing one. 

Let me give you a motivating example: We may want to retain all versions for a given TTL, and then only a specific number of versions. This can be achieved with VERSIONS=INT_MAX, TTL=_retention_interval_, KEEP_DELETED_CELLS=TTL, MIN_VERSION=_num_versions_ . This is not intuitive though because VERSIONS has been used to specify the number of versions to retain (_num_versions_ in this example) since HBase version 0.1, so this is going to be a source of confusion - I've seen it in practice. 

A literate builder API, by way if its method names, could let a user describe more or less in speaking language how they want version retention to work, and internally the builder API could set the low level schema attributes. 

  was:
Lars designed the combination of VERSIONS, TTL, MIN_VERSIONS, and KEEP_DELETED_CELLS with a maximum of flexibility. There is a lot of nuance regarding their usage. Almost all combinations of these four settings make sense for some use cases (exceptions are MIN_VERSIONS > 0 without TTL, and KEEP_DELETED_CELLS=TTL without TTL). There should be a way to make the behavior with TTL easier to conceive when creating the schema. This could take the form of a literate builder API for ColumnDescriptor or an extension to an existing one. 

Let me give you a motivating example: We may want to retain all versions for a given TTL, and then only a specific number of versions. This can be achieved with VERSIONS=INT_MAX, TTL=_retention_interval_, KEEP_DELETED_CELLS=TTL, MIN_VERSION=_num_versions_ . This is not intuitive though because VERSIONS has been used to specify _num_versions_ in this example since version 0.1.

A literate builder API, by way if its method names, could let a user describe more or less in speaking language how they want version retention to work, and internally the builder API could set the low level schema attributes. 


> Literate builder API for version management in schema
> -----------------------------------------------------
>
>                 Key: HBASE-23678
>                 URL: https://issues.apache.org/jira/browse/HBASE-23678
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Andrew Kyle Purtell
>            Priority: Major
>
> Lars designed the combination of VERSIONS, TTL, MIN_VERSIONS, and KEEP_DELETED_CELLS with a maximum of flexibility. There is a lot of nuance regarding their usage. Almost all combinations of these four settings make sense for some use cases (exceptions are MIN_VERSIONS > 0 without TTL, and KEEP_DELETED_CELLS=TTL without TTL). There should be a way to make the behavior with TTL easier to conceive when creating the schema. This could take the form of a literate builder API for ColumnDescriptor or an extension to an existing one. 
> Let me give you a motivating example: We may want to retain all versions for a given TTL, and then only a specific number of versions. This can be achieved with VERSIONS=INT_MAX, TTL=_retention_interval_, KEEP_DELETED_CELLS=TTL, MIN_VERSION=_num_versions_ . This is not intuitive though because VERSIONS has been used to specify the number of versions to retain (_num_versions_ in this example) since HBase version 0.1, so this is going to be a source of confusion - I've seen it in practice. 
> A literate builder API, by way if its method names, could let a user describe more or less in speaking language how they want version retention to work, and internally the builder API could set the low level schema attributes. 



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