First, the advantages:
1) Mass Storage
Hbase PB level adapted to store huge amounts of data, and can return the data in the tens to hundreds of milliseconds at the level of the data PB and PC stored in the case of inexpensive. This is closely related to the highly scalable Hbase. Because formal Hbase good scalability, it provides a convenient mass data storage.
2) Column storage
where the storage column is the fact, that column group (ColumnFamily) storage, Hbase according to data stored in a column group. The following column family can have a lot of columns, column family must be specified when creating the table.
3) extended easily
scalable Hbase mainly in two aspects, is based on a processing capacity of the upper extension (RegionServer), one is based on the extended storage (HDFS).
By adding lateral RegionSever machines, horizontal expansion enhance Hbase upper processing capabilities, enhance the ability to serve more Hbsae the Region.
Note: the role is to manage RegionServer Region, following a service access, the detailed description will be later added through the lateral Datanode machine, for expansion of the storage layer, to enhance the data storage capacity and enhance literacy Hbase back-end storage.
4) high concurrency (multi-core)
due to the current low-cost PC using the most Hbase architecture, are used, so a single IO latency actually is not small, generally between tens to hundreds of ms. Here that high concurrency, mainly in the case of concurrent IO Hbase single drop is not much of a delay. To achieve high concurrency, low latency service.
5) sparse
sparse mainly for flexibility Hbase column, the column family, you can specify any number of columns, column data in the case of empty, will not take up storage space.
Second, shortcomings:
1 can not support a query condition, only support Row key according to the query.
2 is temporarily unable to support failover Master Server's, Master when down, the entire storage system will hang.
Added:
1. Data types, Hbase only a simple character types, all types are treated by the users themselves, save only the string. The relational database is rich in type and storage.
2. Data Manipulation: HBase only a simple insert, search, delete, and other operations between the empty tables and tables are separated, there is no relationship between the table and the table complex, and often have a wide variety of traditional database and connecting operation function.
3. Storage Mode: HBase is stored based on the column, each column group is composed of several file is saved, the separation column at different file group. The traditional relational database table structure is stored on-line mode and
4. The data maintenance, HBase update operation update should not be called, it is actually inserting a new data is to replace the traditional database modification
5. Scalability , Hbase this type of distributed database is developed for this purpose, so it can easily increase or decrease the amount of hardware, and the compatibility of the error is relatively high. The traditional databases often need to increase the intermediate layer in order to achieve similar functionality
Extension: the difference between the row and column storage in storage
can be seen from the figure, the data row of a table storage are put together, but the storage columns are saved separately.
Advantages and disadvantages of the line stored:
Advantages: the data is stored together; INSERT / UPDATE readily
drawbacks: the selection (Selection) even involves only a few columns, all the data will also be read
The advantages and disadvantages of storage columns:
advantages: only relates to the column are read query; Projection (Projection) is efficient; any column can be used as an index
drawbacks: the selection is completed to re-assemble the selected column; INSERT / UPDATE kind of hard
