mirror of https://github.com/apache/cassandra
002190748b
Adds an opt-in O_DIRECT write path for background SSTable producers, bypassing the OS page cache for data that is unlikely to be re-read soon after being written. Memtable flushes remain buffered. Enabled via two new YAML knobs: - background_write_disk_access_mode: standard (default) | direct - direct_write_buffer_size: 1MiB (default; aligned up to FS block size, auto-grown to fit a worst-case compressed chunk) The path is gated by config, table compression being enabled, and an OperationType allowlist in DataComponent. The allowlist is exhaustive over OperationType: any new value left unclassified fails static initialization. Operations on the DIO path: COMPACTION, MAJOR_COMPACTION, TOMBSTONE_COMPACTION, ANTICOMPACTION, GARBAGE_COLLECT, CLEANUP, UPGRADE_SSTABLES, WRITE, STREAM (chunked receiver only), RELOCATE, UNKNOWN (offline sstablesplit). Operations off the DIO path: - FLUSH (policy: just-flushed data is hot, keep in page cache) - SCRUB (correctness: tryAppend needs mark/resetAndTruncate) - Zero-Copy Streaming (bypasses DataComponent.buildWriter) - Uncompressed writers (only CompressedSequentialWriter has a DIO subclass in this change) StartupChecks fails fast if 'direct' is requested on a platform/FS that does not support O_DIRECT. patch by Sam Lightfoot; reviewed by Ariel Weisberg, Dmitry Konstantinov for CASSANDRA-21134 |
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| anttasks/org/apache/cassandra/anttasks | ||
| bin | ||
| burn/org/apache/cassandra | ||
| conf | ||
| data | ||
| distributed/org/apache/cassandra | ||
| harry/main/org/apache/cassandra | ||
| long/org/apache/cassandra | ||
| memory/org/apache/cassandra/db/compaction | ||
| microbench/org/apache/cassandra/test/microbench | ||
| resources | ||
| simulator | ||
| unit | ||