data.fressian

Make writing footer checksums less expensive or optional

Details

  • Type: Enhancement Enhancement
  • Status: Open Open
  • Priority: Major Major
  • Resolution: Unresolved
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Labels:
    None
  • Approval:
    Incomplete

Description

Problem:
JVM profiler indicates checksums as implemented are a significant bottleneck.

Cause:
impl.RawOutput wraps the provided OutputStream with a CheckedOutputStream. Every time a rawInt is written, CheckedOutputStream calls on its checksum to update itself.

Adler32's update method happens to be native, which may not be germane to the problem.
http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/util/zip/Adler32.java#91

The read side of data.fressian already exposes a knob for checksums to be ignored in RawInput. No such knob exists on the write side.

Checksums are used in the footer methods. They may be extremely useful for data at rest, but may be redundant with other out-of-band mechanisms.

Possible solutions
Buffering so that checksums don't recalculate frequently.
Exposing a knob to control whether write checksums are enabled. This would potentially involve changes with the footer.

Activity

Ghadi Shayban made changes -
Field Original Value New Value
Summary Make writing Adler32 checksums less expensive or optional Make writing footer checksums less expensive or optional
Stuart Halloway made changes -
Approval Incomplete [ 10006 ]

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Dates

  • Created:
    Updated: