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https://issues.apache.org/jira/browse/IMPALA-4865?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tim Armstrong updated IMPALA-4865:
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Summary: Limit size of literal values from constant folding (was: Constant
folding can lead to enormous RPC payloads)
> Limit size of literal values from constant folding
> --------------------------------------------------
>
> Key: IMPALA-4865
> URL: https://issues.apache.org/jira/browse/IMPALA-4865
> Project: IMPALA
> Issue Type: Bug
> Components: Frontend
> Affects Versions: Impala 2.8.0
> Reporter: Henry Robinson
> Priority: Major
> Labels: newbie
>
> Consider (from {{test_insert.py}}) the following query:
> {{create table foo as select repeat('AZ', 128 * 1024 * 1024) as s}}
> {{repeat()}} gets constant-folded into a 256MB expression payload, which is
> then transmitted to every fragment instance that evaluates the expression.
> This can lead to timeouts.
> The workaround is {{ENABLE_EXPR_REWRITES=0}}.
> It's not obvious what the answer is - should the FE be aware of the
> serialized size of an expression when deciding whether to constant fold it?
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