Reduce system call #175
Reduce system call #175
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ZZhongge
commented
Sep 19, 2024
- for log manifest, remove truncate if the previous size is smaller.
- for backup log manifest, not open and close file in each call.
1. for log manifest, remove truncate if the previous size is smaller. 2. for backup log manifest, not open and close file in each call.
src/internal_helper.cc
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| std::string dst_file = filename + ".bak"; | ||
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| try { | ||
| if (!f_ops->exist(dst_file)) { |
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Shall we need to check whether the file exist in each call? I tested it and even if the file is removed, all system call will success, but no file is persisted.
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Do you mean if dst_file does not exist, but *file != nullptr, all below pwrite succeeds, but nothing is written? Then yes.
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Yes. So, shall we need to rebuild the *file pointer here? Or we can ignore this case?
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Yes we should, otherwise backup won't be working.
src/internal_helper.cc
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| f_ops->fsync(*file); | ||
| } | ||
| return s; | ||
| } catch (Status s) { |
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Should be 4 spaces, currently 3.
| *file = nullptr; | ||
| } | ||
| return s; | ||
| } |
src/internal_helper.cc
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| std::string dst_file = filename + ".bak"; | ||
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||
| try { | ||
| if (!f_ops->exist(dst_file)) { |
There was a problem hiding this comment.
Do you mean if dst_file does not exist, but *file != nullptr, all below pwrite succeeds, but nothing is written? Then yes.
src/internal_helper.cc
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| ctx.data + bytes_to_skip, | ||
| length - bytes_to_skip, | ||
| bytes_to_skip ) ); |