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Posted to issues@ignite.apache.org by "Andrey Mashenkov (Jira)" <ji...@apache.org> on 2021/05/28 11:45:00 UTC
[jira] [Assigned] (IGNITE-14743) Support Row with large values.
[ https://issues.apache.org/jira/browse/IGNITE-14743?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Andrey Mashenkov reassigned IGNITE-14743:
-----------------------------------------
Assignee: Andrey Mashenkov
> Support Row with large values.
> ------------------------------
>
> Key: IGNITE-14743
> URL: https://issues.apache.org/jira/browse/IGNITE-14743
> Project: Ignite
> Issue Type: Improvement
> Reporter: Andrey Mashenkov
> Assignee: Andrey Mashenkov
> Priority: Major
> Labels: iep-54, ignite-3
> Fix For: 3.0.0-alpha3
>
>
> 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.
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