performance problem caused by sync_index ?

 Hi, We're experiencing a regular slow down of our application.
I'm analyzing an AWR report (snapshots frequency=a quarter of hour)

It shows ctxsys.ctx_ddl.sync_index on the top of expensive sql orders.
Could it be the source of our problems?
How could I solve that?

It seems the procédure sync_index is ran automatically at a particular frequency.
In which table could I find that frequency?

Please find the report below.

Regards,

Frederic

body.awr {font:bold 10pt Arial,Helvetica,Geneva,sans-serif;color:black; background:White;} pre.awr {font:8pt Courier;color:black; background:White;}h1.awr {font:bold 20pt Arial,Helvetica,Geneva,sans-serif;color:#336699;background-color:White;border-bottom:1px solid #cccc99;margin-top:0pt; margin-bottom:0pt;padding:0px 0px 0px 0px;} h2.awr {font:bold 18pt Arial,Helvetica,Geneva,sans-serif;color:#336699;background-color:White;margin-top:4pt; margin-bottom:0pt;} h3.awr {font:bold 16pt Arial,Helvetica,Geneva,sans-serif;color:#336699;background-color:White;margin-top:4pt; margin-bottom:0pt;}li.awr {font: 8pt Arial,Helvetica,Geneva,sans-serif; color:black; background:White;} th.awrnobg {font:bold 8pt Arial,Helvetica,Geneva,sans-serif; color:black; background:White;padding-left:4px; padding-right:4px;padding-bottom:2px}th.awrbg {font:bold 8pt Arial,Helvetica,Geneva,sans-serif; color:White; background:#0066CC;padding-left:4px; padding-right:4px;padding-bottom:2px} td.awrnc {font:8pt Arial,Helvetica,Geneva,sans-serif;color:black;background:White;vertical-align:top;} td.awrc {font:8pt Arial,Helvetica,Geneva,sans-serif;color:black;background:#FFFFCC; vertical-align:top;}a.awr {font:bold 8pt Arial,Helvetica,sans-serif;color:#663300; vertical-align:top;margin-top:0pt; margin-bottom:0pt;}