51c345aaf6
Previously, rewriting an sstable component (e.g., via rewrite_statistics) created a temporary file that was renamed to the final name after sealing. This allows crash recovery by simply removing the temporary file on startup. However, this approach won't work once component digests are stored in scylla_metadata, as replacing a component like Statistics will require atomically updating both the component and scylla_metadata with the new digest—impossible with POSIX rename. The new mechanism creates a clone sstable with a fresh generation: - Hard-links all components from the source except the component being rewritten and scylla metadata if update_sstable_id is true - Copies original sstable components pointer and recognized components from the source - Invokes a modifier callback to adjust the new sstable before rewriting - Writes the modified component. If update_sstable_id is true, reads scylla metadata, generates new sstable_id and rewrites it. - Seals the new sstable with a temporary TOC - Replaces the old sstable atomically, the same way as it is done in compaction This is built on the rewrite_sstables compaction framework to support batch operations (e.g., following incremental repair). In case of any failure during the whole process, sstable will be automatically deleted on the node startup due to temporary toc persistence. This prepares the infrastructure for component digests. Once digests are introduced in scylla_metadata this mechanism will be extended to also rewrite scylla metadata with the updated digest alongside the modified component, ensuring atomic updates of both.
21 KiB
21 KiB