如何在PostgreSQL 9.2中索引JSON数据？

Question

Does anyone know how to create index on JSON data in PostgreSQL 9.2?

Example data:

[
  {"key" : "k1", "value" : "v1"},
  {"key" : "k2", "value" : "v2"}
]

Say if I want to index on all the keys how to do that?

Thanks.

Answer 1

You are much better off using hstore for indexed fields, at least for now.

CREATE INDEX table_name_gin_data ON table_name USING GIN(data);

You can also create GIST indexes if you are interested in fulltext search. More info here: http://www.postgresql.org/docs/9.0/static/textsearch-indexes.html

Answer 2

Currently there are no built-in functions to index JSON directly. But you can do it with a function based index where the function is written in JavaScript.

See this blog post for details: http://people.planetpostgresql.org/andrew/index.php?/archives/249-Using-PLV8-to-index-JSON.html

There is another blog post from which talks about JSON and how it can be used with JavaScript: http://www.postgresonline.com/journal/archives/272-Using-PLV8-to-build-JSON-selectors.html

Answer 3

This question is a little old but I think the selected answer is not really the ideal one. To index json (the property values inside json text), we can use expression indexes with PLV8 (suggested by @a_horse_with_no_name).

Craig Kerstein does a great job of explaining/demonstrating:

http://www.craigkerstiens.com/2013/05/29/postgres-indexes-expression-or-functional-indexes/