5

This may be premature, postgres 9.4 is still in beta. I've been experimenting with the jsonb type. I am not having any luck passing a jsonb type to a plv8 function, it comes in as type string. I was wondering if I was doing it wrong?

create or replace function jt ( o json ) returns integer language plv8 immutable
AS $function$
        plv8.elog(INFO, 'type is ', typeof o);
        plv8.elog(INFO, 'argument is ', o);
        plv8.elog(INFO, 'member is ', o['member']);
$function$;

create or replace function jt ( o jsonb ) returns integer language plv8 immutable
AS $function$
        plv8.elog(INFO, 'type is ', typeof o);
        plv8.elog(INFO, 'argument is ', o);
        plv8.elog(INFO, 'member is ', o['member']);
$function$;

then, when I run using json:

psql=# select jt('{"member":"test"}'::json);
INFO:  type is  object
INFO:  argument is  [object Object]
INFO:  member is  test

but, when I run with jsonb:

psql=# select jt('{"member":"test"}'::jsonb);
INFO:  type is  string
INFO:  argument is  {"member": "test"}
INFO:  member is  undefined

-g

Greg
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1 Answers1

5

PL/V8 will need to add support for JSONB before this works how you expect.

In the mean time you can still pass plain json; just cast the jsonb to json.

News since ~2015

plv8 project changed after 2014, as this comment of the project's sponsor and main contributor, JerrySievert, in 2017:

the JSONB vs JSON speed differences were well known and addressed,
JSONB now does a direct conversion in C++ into v8 objects and runs faster than a JSON conversion

The last revision history show some clues about JSONb starting date:

  • in 2015-05-26 (version 1.4.4 ) "Add jsonb type coercion in function boundary".

  • in 2019-03-23 (version 2.3.10) "add direct jsonb conversion option", "add memory context for jsonb conversion".

The suggestion is to use JSONB with plv8 version 2.3.10 or later... Still, for older versions of plv8, Jarry confirmed that almost everything will be fine:

JSONB support has been active and complete since April 22, 2015.

Peter Krauss
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Craig Ringer
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  • Hi, please update... Or [check if it was really updated](https://github.com/plv8/plv8/issues/402#issuecomment-667599822). – Peter Krauss Aug 02 '20 at 21:10
  • @PeterKrauss Please propose an edit with the information you want shown. I can't keep track of everything. Note the 2014 answer date. – Craig Ringer Aug 02 '20 at 23:55
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    Hi, sorry, I uninstalled plv8, no way to check empirical evidence... I am editing your question with the news. Comment **for other readers**: please check (by performance) that it is really JSONb input, not a syntax sugar (automatic cast `JSONb::text`). – Peter Krauss Aug 03 '20 at 10:38
  • @PeterKrauss Thanks very much, appreciated. – Craig Ringer Aug 05 '20 at 13:06