Re: json accessors - Mailing list pgsql-hackers

From David E. Wheeler
Subject Re: json accessors
Date
Msg-id 343A16DA-0C4B-41F3-8E18-51FBA5A29E48@justatheory.com
Whole thread Raw
In response to Re: json accessors  (Merlin Moncure <mmoncure@gmail.com>)
Responses Re: json accessors
Re: json accessors
List pgsql-hackers
On Nov 28, 2012, at 4:10 PM, Merlin Moncure <mmoncure@gmail.com> wrote:

>> Yes, it's iterative. And for deeply nested json it might be somewhat
>> inefficient, although the parser is pretty fast AFAICT. But it's a start.
>
> not completely buying that: see comments below.  not supporting xpath
> style decompositions seems wrong to me.  IOW, json_get should be set
> returning (perhaps via wild cards in the keytext) or we need
> json_each.

The problem I see with the current proposal is that this limitation, it seems to me, would prevent the ability to index
nestedkeys. If you're essentially composing and decomposing JSON values as you drill down, the intermediate JSON values
betweenthe original one and the final return value can't be indexed, can they? 

For sufficiently large columns, I expect I would want a GIN index to speed JSON value extraction queries. Possible with
thisproposal? 

Best,

David

PS: SOrry for the delayed replies, digging my way out of a couple weeks of back posts…




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