Igor Canadi f26cb0f093 Optimize fallocation ... Summary: Based on my recent findings (posted in our internal group), if we use fallocate without KEEP_SIZE flag, we get superior performance of fdatasync() in append-only workloads. This diff provides an option for user to not use KEEP_SIZE flag, thus optimizing his sync performance by up to 2x-3x. At one point we also just called posix_fallocate instead of fallocate, which isn't very fast: http://code.woboq.org/userspace/glibc/sysdeps/posix/posix_fallocate.c.html (tl;dr it manually writes out zero bytes to allocate storage). This diff also fixes that, by first calling fallocate and then posix_fallocate if fallocate is not supported. Test Plan: make check Reviewers: dhruba, sdong, haobo, ljin Reviewed By: dhruba CC: leveldb Differential Revision: https://reviews.facebook.net/D16761		2014-03-17 21:52:14 -07:00
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rocksdb	Optimize fallocation	2014-03-17 21:52:14 -07:00
utilities	keep_log_files option in BackupableDB	2014-03-17 15:39:23 -07:00