Discussion on "For Speeds Sake, Stop Using APEX_JSON"

Jon Dixon · 2022-06-05T14:10:15.496Z

Introduction Before I start, I should say the APEX_JSON PL/SQL API (available since APEX 5.0) is one of the most useful APIs the APEX development team have provided. I have used APEX_JSON to generate and parse JSON on countless occasions. It served m...

Hi Jon,

The json_object_t.PUT procedure does not escape multi-byte characters like apex_json.write does. ie apex_json.write('1', '£'); -- {"1":"\u00A3"} l_json.PUT('2', '£'); -- {"2":"£"}
and l_json.PUT('4', APEX_ESCAPE.JSON('£')); -- {"3":"\u00A3"}

And one does not appear to be able to escape the input to PUT without a '\' getting escaped into '\\' by the PUT procedure.

Some REST API's require multi-byte characters to be escaped , which is definitly a problem for me.

You are right. It escapes json embedded in the text but does not escape multi-byte characters. I have not found this to be an issue with the web services I have built, but that is good to know.

Hi Jon, thanks for your article!

After moving an implementation of generating JSON output for ORDS from APEX_JSON to JSON_OBJECT_T, we saw that:

generating the JSON itself became faster, but for some reason
"printing" it to ORDS is significantly slower using JSON_OBJECT_T than it is with APEX_JSON.

Out of interest, can you reproduce this behavior in your tests, or does adding "apex_util.prn ( l_json_clob, false );" take the same time, independent if the CLOB comes from JSON_OBJECT_T or APEX_JSON?

BR Paul

Hi Paul. I haven't run this specific test, but I assume apex_util.prn takes the same amount of time regardless of what generated the CLOB. Could it be that JSON_OBJECT_T is generating a larger CLOB? Maybe try comparing the size of the CLOB using each method.

Jon Dixon yeah, I'd assume the same. The CLOBs are different, APEX_JSON seems to escape string values ("O'Brien" becomes "O\u0027Brien") resulting in a bigger CLOB, but faster print performance.

Escaping string values in JSON_OBJECT_T (using e.g. apex_escape.json) improves the print performance, but the serialization (to_clob) messes up the output by adding an additional backslash ("O'Brien" becomes "O\\u0027Brien").

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For Speeds Sake, Stop Using APEX_JSON

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