hstore is more of a "wide column" storage type, it is a flat (non-nested) dictionary of key-value pairs, always stored in a reasonably efficient binary format (a hash table, hence the name). json stores JSON documents as text, performing validation when the documents are stored, and parsing them on output if needed (i.e. accessing individual fields); it should support the entire JSON spec. Since the entire JSON text is stored, its formatting is preserved. jsonb takes shortcuts for performance reasons: JSON data is parsed on input and stored in binary format, key orderings in dictionaries are not maintained, and neither are duplicate keys. Accessing individual elements in the JSONB field is fast as it doesn't require parsing the JSON text all the time. On output, JSON data is reconstructed and initial formatting is lost.

在我看来，如果您处理的是机器可读的数据，那么一旦jsonb可用，就没有什么重要的理由不使用它。

Peeyush:

简单的回答是:

如果你在PostgreSQL中做很多JSON操作，比如排序、切片、拼接等，出于速度考虑，你应该使用JSONB。 如果需要对JSON上的任意键搜索进行索引查找，那么应该使用JSONB。 如果以上两种方法都不使用，则可能应该使用JSON。 如果需要保留键顺序、空格和重复的键，则应该使用JSON。

想要得到更长的答案，你需要等我在9.4发行版之前写一篇完整的“HowTo”文章。

我今天在PostgresOpen上，基准测试比MongoDB快多了。我相信它的选择速度快了500%。几乎所有东西都更快，与MongoDB相比至少快了200%。现在的一个例外是需要完全重写整个JSON列的更新——这一点MongoDB处理得更好。

JSONB上的gin索引听起来很棒。

PostgreSQL还将在内部持久化JSONB类型，并将其与数字、文本、布尔等类型进行匹配。

使用JSONB也可以实现连接。

为存储过程添加PLv8，这将是Node.js开发者的梦想成真。

由于它被存储为二进制，JSONB还将删除所有空白，改变属性的顺序，并使用属性的最后一次出现来删除重复的属性。

除了索引，当查询JSONB列和JSON列时，PostgreSQL不需要实际运行将每一行的文本转换为JSON的功能，这可能会节省大量的时间。

据我所知

hstore as it currently exists (in PostgreSQL 9.3) does not allow for nesting other objects and arrays as the values of its key/value pairs. However, a future hstore patch will allow for nesting. This patch will not be in the 9.4 release and may not be included any time soon. json as it currently exists does allow for nesting, but it is text-based and does not allow for indexing, thus it is "slow" jsonb that will be released with 9.4 will have the current nesting capabilities of json, as well as the GIN/GIST indexing of hstore, so it will be fast

开发PostgreSQL 9.4的人似乎在说，新的、快速的jsonb类型将吸引那些选择使用像MongoDB这样的NoSQL数据存储的人，但它现在可以将关系数据库和可查询的非结构化数据组合在一个框架下

为什么HStore2/jsonb是9.4最重要的补丁

PostgreSQL 9.4 jsonb的基准测试似乎与MongoDB相当，在某些情况下甚至比MongoDB更快。

http://texture.io/alphabetum/postgresql-incl-hstore-vs-mongodb

json和jsonb之间的区别的简单解释(原始图片来自PostgresProfessional):

SELECT '{"c":0,   "a":2,"a":1}'::json, '{"c":0,   "a":2,"a":1}'::jsonb;

          json          |        jsonb 
------------------------+--------------------- 
 {"c":0,   "a":2,"a":1} | {"a": 1, "c": 0} 
(1 row)

Json:文本存储«as is» Jsonb:没有空格 没有重复的键，最后一个键获胜 Jsonb:键排序

更多的演讲视频和幻灯片演示由jsonb开发人员。他们还引入了JsQuery，一个pg.extension，提供了强大的jsonb查询语言。

JSONB是JSON的“更好”版本。

让我们来看一个例子:

SELECT '{"c":0,   "a":2,"a":1}'::json, '{"c":0,   "a":2,"a":1}'::jsonb;

          json          |        jsonb 
------------------------+--------------------- 
 {"c":0,   "a":2,"a":1} | {"a": 1, "c": 0} 
(1 row)

JSON stores white space, and that is why we can see spaces when key "a" is stored, while JSONB does not. JSON stores all the values of a key. This is the reason you can see multiple values (2 and 1) against the key "a" , while JSONB only "stores" the last value. JSON maintains the order in which elements are inserted, while JSONB maintains the "sorted" order. JSONB objects are stored as a decompressed binary as opposed to "raw data" in JSON, where no reparsing of data is required during retrieval. JSONB also supports indexing, which can be a significant advantage.

一般来说，应该更喜欢JSONB，除非有特殊的需要，比如对对象键的顺序有遗留的假设。