介绍
V$RMAN_COMPRESSION_ALGORITHM视图提供了查询当前数据库RMAN支持的压缩算法的方法。
视图详情
字段名 | 字段类型 | 描述 | 译 | 备注 |
ALGORITHM_ID | NUMBER | Algorithm ID | 压缩算法ID | |
ALGORITHM_NAME | VARCHAR2(64) | Name of the algorithm (for example, LOW, MEDIUM, DEFAULT, or HIGH) | 压缩算法名称,例如:低级、介质、默认或高级 | |
INITIAL_RELEASE | VARCHAR2(18) | First Oracle Database release when this compression algorithm was available | 压缩算法支持的初始Oracle版本 | |
TERMINAL_RELEASE | VARCHAR2(18) | Last Oracle Database release that supported using this compression algorithm to create new backups. Existing backups can always be restored, even if they use a deprecated compression algorithm. | 压缩算法支持的的最后Oracle版本 | 即使新版本的Oracle已不支持该压缩算法,也能恢复使用了被弃用的压缩算法备份的备份集 |
ALGORITHM_DESCRIPTION | VARCHAR2(64) | Description of the algorithm | 压缩算法的描述 | |
ALGORITHM_COMPATIBILITY | VARCHAR2(18) | Required database compatibility level for the algorithm (for example, 11.2.0 for DEFAULT) | 压缩算法所需的数据库兼容性级别 | |
IS_VALID | VARCHAR2(3) | Indicates whether the algorithm is valid with regard to the compatibility setting (YES) or not (NO). The value is YES if ALGORITHM_COMPATIBILITY <= DATABASE_COMPATIBILITY. | 压缩算法是否对兼容性设置有效,如果ALGORITHM_COMPATIBILITY <= DATABASE_COMPATIBILITY,则有效(YES) | |
REQUIRES_ACO | VARCHAR2(3) | Indicates whether the algorithm requires the Advanced Compression Option (YES) or not (NO) | 压缩算法是否需要高级压缩选项,YES-需要,NO-不需要 | |
IS_DEFAULT | VARCHAR2(3) | Indicates whether the algorithm is the default compression algorithm that RMAN uses to create compressed backup sets (YES) or not (NO) | 压缩算法是否为RMAN创建压缩备份集的默认算法,YES-默认算法,NO-不是默认算法 |
压缩算法说明
当前为Oracle 11G的压缩算法说明。
压缩算法名称 | 压缩算法初始版本 | 压缩算法最后版本 | 压缩算法说明 | 备注 |
BZIP2 | 10.0.0.0.0 | 11.2.0.0.0 | 压缩率高,但速度慢 | |
BASIC | 10.0.0.0.0 | 压缩率高,但速度慢 | ||
LOW | 11.2.0.0.0 | 压缩速度快,但压缩率低 | ||
ZLIB | 11.0.0.0.0 | 11.2.0.0.0 | 平衡压缩率和压缩速度,算是压缩率和压缩速度适中 | |
MEDIUM | 11.2.0.0.0 | 平衡压缩率和压缩速度,算是压缩率和压缩速度适中 | Oracle建议使用此压缩 | |
HIGH | 11.2.0.0.0 | 最大压缩率,压缩速度极慢 |
评论区