Eliminate some redundant block reads. #3354
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Re-use metadata for reading Compression Dictionary on BlockBased table open, this saves two reads from disk.
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@yuslepukhin has updated the pull request. View: changes |
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Just curious, are you using dictionary compression in production? If so, are you able to share any details about the benefit you see on compression ratio? We don't use it yet but hope to some day. |
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@ajkr I take that back. We are not using compression dictionary and the perf gain comes from issuing parallel reads in async version. This PR may not be that useful after all. |
ajkr
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Jan 10, 2018
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amytai
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Mar 9, 2018
Summary: Re-use metadata for reading Compression Dictionary on BlockBased table open, this saves two reads from disk. This helps to our 999 percentile in 5.6.1 where prefetch buffer is not present. Closes facebook#3354 Differential Revision: D6695753 Pulled By: ajkr fbshipit-source-id: bb8acd9e9e66e65b89c548ab8940570ae360333c
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Re-use metadata for reading Compression Dictionary on BlockBased
table open, this saves two reads from disk.
This helps to our 999 percentile in 5.6.1 where prefetch buffer is not present.