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https://issues.apache.org/jira/browse/IGNITE-1770?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14978228#comment-14978228
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Vladimir Ozerov commented on IGNITE-1770:
-----------------------------------------
I propose picking FNV1 algo for schema ID calculation. It offers pretty nice
distribution. Using it shows minimal performance drop during object write
(~1-2% in Java with standard Address object).
{code}
private static final int FNV1_OFFSET_BASIS = 0x811C9DC5;
private static final int FNV1_PRIME = 0x01000193;
int schemaId = FNV1_OFFSET_BASIS;
void onFieldAdded(int fieldId) {
int schemaId0 = schemaId ^ (fieldId & 0xFF);
schemaId0 = schemaId0 * FNV1_PRIME;
schemaId0 = schemaId0 ^ ((fieldId >> 8) & 0xFF);
schemaId0 = schemaId0 * FNV1_PRIME;
schemaId0 = schemaId0 ^ ((fieldId >> 16) & 0xFF);
schemaId0 = schemaId0 * FNV1_PRIME;
schemaId0 = schemaId0 ^ ((fieldId >> 24) & 0xFF);
schemaId0 = schemaId0 * FNV1_PRIME;
schemaId = schemaId0;
}
{code}
> Portables: implement constant-time field lookup.
> ------------------------------------------------
>
> Key: IGNITE-1770
> URL: https://issues.apache.org/jira/browse/IGNITE-1770
> Project: Ignite
> Issue Type: Task
> Components: general, interop
> Affects Versions: ignite-1.4
> Reporter: Vladimir Ozerov
> Assignee: Vladimir Ozerov
> Priority: Blocker
> Fix For: 1.5
>
>
> See
> https://cwiki.apache.org/confluence/display/IGNITE/Portable+object+constant-time+field+lookup
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