Sagar Vemuri 89ad9f3adb Allow ignoring unknown options when loading options from a file ... Summary: Added a flag, `ignore_unknown_options`, to skip unknown options when loading an options file (using `LoadLatestOptions`/`LoadOptionsFromFile`) or while verifying options (using `CheckOptionsCompatibility`). This will help in downgrading the db to an older version. Also added `--ignore_unknown_options` flag to ldb **Example Use case:** In MyRocks, if copying from newer version to older version, it is often impossible to start because of new RocksDB options that don't exist in older version, even though data format is compatible. MyRocks uses these load and verify functions in [ha_rocksdb.cc::check_rocksdb_options_compatibility](e004fd9f41/storage/rocksdb/ha_rocksdb.cc (L3348-L3401)). **Test Plan:** Updated the unit tests. `make check` ldb: $ ./ldb --db=/tmp/test_db --create_if_missing put a1 b1 OK Now edit /tmp/test_db/<OPTIONS-file> and add an unknown option. Try loading the options now, and it fails: $ ./ldb --db=/tmp/test_db --try_load_options get a1 Failed: Invalid argument: Unrecognized option DBOptions:: abcd Passes with the new --ignore_unknown_options flag $ ./ldb --db=/tmp/test_db --try_load_options --ignore_unknown_options get a1 b1 Closes https://github.com/facebook/rocksdb/pull/2423 Differential Revision: D5212091 Pulled By: sagar0 fbshipit-source-id: 2ec17636feb47dc0351b53a77e5f15ef7cbf2ca7		2017-06-13 16:58:01 -07:00
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rocksdb	Allow ignoring unknown options when loading options from a file	2017-06-13 16:58:01 -07:00