Konstantin Orlov created IGNITE-12688:
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Summary: Improve performance of index inline JAVA_OBJECT fields
Key: IGNITE-12688
URL: https://issues.apache.org/jira/browse/IGNITE-12688
Project: Ignite
Issue Type: Bug
Reporter: Konstantin Orlov
Assignee: Konstantin Orlov
Inline JAVA_OBJECT may be reason of performance drop on index creation.
The *root cause* is the low selectivity of current part of JAVA_OBJECT that is
inlined.
Now first N bytes of binary view of object is placed into inline space of the
index.
But the first offset where the two objects with the same type may be different
is 8 (HASH_CODE_POS).
With default inline = 10 we NEVER inline it:
Inline format:
1 byte - type,
2 bytes - size
>> 7 bytes - data;
*My proposal:*
- For metapage v4 (BPlusMetaIO) add flag *inlineObjectHash*;
- use this flag to work in compatibility mode.
- inline ONLY hash for JAVA_OBJECT fields for new indexes;
Also this approach solves the inconsistent between comparison JAVA_OBJECT by
inline and full value, because value comparator uses hash to compare object
before compare byte arrays.
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