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https://issues.apache.org/jira/browse/IGNITE-29206?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dmitry Werner updated IGNITE-29206:
-----------------------------------
Affects Version/s: 2.19
> Serialize compressed and raw fields in DirectMessageWriter through a
> fixed-size buffer
> --------------------------------------------------------------------------------------
>
> Key: IGNITE-29206
> URL: https://issues.apache.org/jira/browse/IGNITE-29206
> Project: Ignite
> Issue Type: Improvement
> Affects Versions: 2.19
> Reporter: Dmitry Werner
> Assignee: Dmitry Werner
> Priority: Major
> Labels: ise
> Fix For: 2.20
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> *Motivation*
> DirectMessageWriter serializes @Compress and pending raw fields by
> accumulating the whole field in a reusable heap buffer (tmpBuf), which
> doubles until the field fits and is never shrunk. Writers are long-lived (per
> NIO session for communication, per node for discovery), so each one retains a
> buffer up to ~2x the largest field it has ever serialized. Growing it also
> copies the data and allocates humongous arrays.
> The exchange coordinator is hit hardest: compressed fields of
> GridDhtPartitionsFullMessage can reach tens of megabytes, and after a PME
> every communication session keeps such a buffer, which can add up to hundreds
> of megabytes of heap on large clusters. The retention was introduced in
> IGNITE-28836.
> Also, if serialization throws, tmpWriter keeps stale nested state that a
> later field could continue from. Current callers drop the writer after an
> error, so this is hardening.
> *Changes*
> The temporary buffer has a fixed size of 10 KB. The field is serialized into
> it piece by piece, like into a socket buffer, and each piece is handed to a
> consumer.
> @Compress fields are deflated on the fly by the new
> CompressedMessage.Compressor, so the raw data is never held in one buffer.
> The wire format is unchanged.
> Raw fields are collected piece by piece and joined into a single byte array.
> If serialization fails, tmpWriter is dropped, as DirectMessageReader already
> does with tmpReader.
> Effect: each writer retains a constant 10 KB instead of the largest field
> ever sent. Small fields (the vast majority) fit in a single piece, as before.
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