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The "FAQ_JP" page has been changed by MakiWatanabe. The comment on this change is: Translate short answers. http://wiki.apache.org/cassandra/FAQ_JP?action=diff&rev1=74&rev2=75 -------------------------------------------------- <<Anchor(a_long_is_exactly_8_bytes)>> - == Insert operation throws InvalidRequestException with message "A long is exactly 8 bytes" == + == 挿入操作でInvalidRequestExeptionが発生し，次のようなメッセージが出力されます:"A long is exactly 8 bytes" == You are propably using !LongType column sorter in your column family. !LongType assumes that the numbers stored into column names are exactly 64bit (8 bytes) long and in big endian format. Example code how to pack and unpack an integer for storing into cassandra and unpacking it for php: {{{ @@ -381, +381 @@ <<Anchor(batch_mutate_atomic)>> - == Are batch_mutate operations atomic? == + == batch_mutateはアトミックな操作ですか? == As a special case, mutations against a single key are atomic but not isolated. Reads which occur during such a mutation may see part of the write before they see the whole thing. More generally, batch_mutate operations are not atomic. [[API#batch_mutate|batch_mutate]] allows grouping operations on many keys into a single call in order to save on the cost of network round-trips. If `batch_mutate` fails in the middle of its list of mutations, no rollback occurs and the mutations that have already been applied stay applied. The client should typically retry the `batch_mutate` operation. <<Anchor(hadoop_support)>> @@ -390, +390 @@ Hadoop-Cassandra統合の最新情報については, [[HadoopSupport_JP|HadoopSupport]] をご覧ください. + <<Anchor(multi_tenant)>> - == Can a Cassandra cluster be multi-tenant? == - There is work being done to support more multi-tenant capabilities such as scheduling and auth. For more information, see MultiTenant. + == Cassandraクラスタはマルチテナント運用可能ですか? == + スケジューリングや認証など、マルチテナント機能をより充実するための取り組みが行われています。詳しくはMultiTenantを参照して下さい。 <<Anchor(using_cassandra)>> - == Who is using Cassandra and for what? == - For information on who is using Cassandra and what they are using it for, see CassandraUsers. + == どんなユーザが何のためにCassandraを使っているのでしょうか? == + Cassandraを使用しているユーザや、その用途についてはCassandraUsersを参照して下さい。 <<Anchor(what_about_the_obdc)>> - == Are there any OBDC drivers for Cassandra? == - No. + == Cassandra用のODBCドライバはありませんか？ == + ありません。 <<Anchor(logging_using_cassandra)>> - == Are there ways to do logging directly to Cassandra? == - For information on logging directly to Cassandra, see LoggingToCassandra. + == Cassandraに直接ログを記録する方法はありますか？ == + Cassandraに直接ログする方法についてはLoggingToCassandraを参照して下さい。 <<Anchor(rhel_selinux)>> - == On RHEL nodes are unable to join the ring == - Check if selinux is on, if it is turn it OFF + == RedHat Enterprise Linuxを使う上で何か問題はありますか？ == + もしselinuxがONになっていたら、OFFにしてください。 <<Anchor(auth)>> - == Is there an authentication/authorization mechanism for Cassandra? == - Yes. For details, see ExtensibleAuth. + == 認証・権限付与の機能はありますか？ == + あります。詳細についてはExtensibleAuthを参照して下さい。 <<Anchor(bulkloading)>> - == How do I bulk load data into Cassandra? == - See BulkLoading + == データをバルクロードするにはどうしたらいいでしょうか？ == + BulkLoadingを参照して下さい。 + <<Anchor(range_rp)>> - == Why aren't range slices/sequential scans giving me the expected results? == + == レンジスライスやシーケンシャルスキャンはなぜ期待通りの結果を返さないのでしょうか？ == You're probably using the RandomPartitioner. This is the default because it avoids hotspots, but it means your rows are ordered by the md5 of the row key rather than lexicographically by the raw key bytes. You '''can''' start out with a start key and end key of [empty] and use the row count argument instead, if your goal is paging the rows. To get the next page, start from the last key you got in the previous page. @@ -436, +438 @@ <<Anchor(unsubscribe)>> - == How do I unsubscribe from the email list? == - Send an email to [email protected] + == メーリングリストの配信を停止するにはどうしたらいいですか？ == + [email protected]にメールを送ってください。 <<Anchor(cleaning_compacted_tables)>> - == I compacted, so why did space used not decrease? == + == Compactionを実行してもディスク使用量が減らないのはなぜでしょうか？ == SSTables that are obsoleted by a compaction are deleted asynchronously when the JVM performs a GC. You can force a GC from jconsole if necessary, but Cassandra will force one itself if it detects that it is low on space. A compaction marker is also added to obsolete sstables so they can be deleted on startup if the server does not perform a GC before being restarted. Read more on this subject [[http://wiki.apache.org/cassandra/MemtableSSTable|here]]. <<Anchor(mmap)>> - == Why does top report that Cassandra is using a lot more memory than the Java heap max? == + == topコマンドの出力で，CassandraがJava heapの最大値よりも大きなメモリを使用しているのはなぜでしょうか？ == Cassandra uses mmap to do zero-copy reads. That is, we use the operating system's virtual memory system to map the sstable data files into the Cassandra process' address space. This will "use" virtual memory; i.e. address space, and will be reported by tools like top accordingly, but on 64 bit systems virtual address space is effectively unlimited so you should not worry about that. What matters from the perspective of "memory use" in the sense as it is normally meant, is the amount of data allocated on brk() or mmap'd /dev/zero, which represent real memory used. The key issue is that for a mmap'd file, there is never a need to retain the data resident in physical memory. Thus, whatever you do keep resident in physical memory is essentially just there as a cache, in the same way as normal I/O will cause the kernel page cache to retain data that you read/write.
