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以下关于MapReduce技术的说法中，不正确的是（ ）。
MapReduce的计算过程分解为两个主要阶段：Map阶段和Reducel阶段，在同等硬件条件下，MapReduce的性能远低于并行数据库。MapReduce中存在数据chunk的冗余复制。
Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.
Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.
Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.
Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.
Corporate decision makers require access to information from multiple such sources. Seting up queries on individual sources is both cumbersome and（ 71 ）. Moreover, the sources of data may store only current data, whereas decision makers may need access to（ 72 ）dataas well. A data warehouse is a repository（or archive）of information gathered from multiple sources, stored under a unified schema, at a（ 73 ）site. Once gathered, the data are stored for a long time, permitting access to historical data. Thus, data warehouses provide the user with a single consolidated（ 74 ）to data, making decision-support queries easier to write. Moreover, by accessing information for decision support from a data warehouse, the decision maker ensures that online transaction- processing systems are not（ 75 ）by the decision-supportworkdoad.
以下关于MapReduce技术的说法中，不正确的是（ ）。
相比于集中式数据库，分布式数据库具有（ ）的优点。
数据仓库是为了构建新的分析处理环境而出现的一种数据存储和组织技术，其特征不包括（ ）。
大数据的特性一般包括（ ）。
①数量大；②速度增长快；③多样性；④价值密度低。
由于机房断电，某个使用检查点记录的数据库出现故障，该故障属于（ ）。
