[jira] [Updated] (IGNITE-14743) Support large Tuples.

["Andrey Mashenkov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-14743?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrey Mashenkov updated IGNITE-14743:
--------------------------------------
    Labels: iep-54 ignite-3  (was: )

> Support large Tuples.
> ---------------------
>
>                 Key: IGNITE-14743
>                 URL: https://issues.apache.org/jira/browse/IGNITE-14743
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Andrey Mashenkov
>            Priority: Major
>              Labels: iep-54, ignite-3
>             Fix For: 3.0
>
>
> For now, TupleAssembler writes offsets for varlen columns as 2-byte {{short }}type.
> This implicitly restricts key/value sizes down to 64 kB in total.
> Let's use 4-bytes {{int}} type for offsets for large tuples.
> Possible ways are:
>  # Just use ints for offsets, this increases the memory overhead for Rows.
>  # Pre-calculate potential row size during SchemaDescriptor initialization and keep 'offset_size' in schema. 
> Unlimited varlen type (which is default) usage will end-up user will have 4-byte offset size in most cases.
>  # Pre-calculate exact tuple size for each row and use row flags. 
> This requires Tuple data analysis which we already do to detect non-null varlen values and nulls. Strings may be a headache as we have to analyze each char for accurate tuple size calculation.
>  # Pre-calculate tuple size skipping chars analysis.
> Using adaptive offset_size approaches allows us to use 1-2-4 byte numbers (byte, short, int) for offsets.
> Collations for String columns may be introduced and used as a hint, but we will need to check a collation for every char on write.
> 'Large keys' is an unwanted case, may a solution for values only will be enough...



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