Disabling indexes on a table

One of my developers asked me about this, and he suggested running the following update:

UPDATE pg_index SET indisready=false
WHERE indrelid = (select oid from pg_class where release = ‘his_table’);

I told him it’s never a good idea to update anything in a system catalog by hand, but that I would reach out here for a better opinion. Am I correct that he shouldn’t try this, or is he OK to do this? His table has approximately 8 different indexes on it, and those really slow down his bulk loads. Usually when I have to get involved, I just drop his indexes and rebuild them afterwards, and I know that is always safe.
—
Jay

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