Re:Re: COPY FROM with RLS

At 2026-05-10 14:23:26, "jian he" <jian(dot)universality(at)gmail(dot)com> wrote:
>Hi. I implemented a hack to make it work with RLS policies that
>contain subqueries; I'm not sure how valid it is.
>
>IF (check_enable_rls(RelationGetRelid(cstate->rel), InvalidOid,
>false) == RLS_ENABLED)
>is true, then we construct a dummy query string:
>
>INSERT INTO "%s"."%s" DEFAULT VALUES
>
>(where %s.%s is replaced by the schema-qualified relation name) and
>then run it through the following pipeline:
>pg_analyze_and_rewrite_fixedparams()
>pg_plan_query()
>CreateQueryDesc()
>ExecutorStart()
>
>Obviously, ExecutorRun() cannot be used because the data source for COPY FROM is
>an external file rather than a normal query execution.
>
>The main hack is to bypass ExecutorRun() completely and only use ExecutorStart()
>to initialize the required executor structures (EState, PlanState,
>ResultRelInfo, etc.) for ExecWithCheckOptions (which is part of
>ExecutorRun normally).
>
>In DoCopy we did converting COPY (REL) TO,to a SelectStmt when REL have RLS.

Hi, I've gone through your v2 patch and there’s an issue I’d like to point out.
In src/test/regress/expected/rowsecurity.out:

+-- COPY FROM should also apply INSERT CHECK policy clause
+COPY rls_test_tgt FROM STDIN WITH (DELIMITER ',');
+ERROR: missing data for column "c"
+CONTEXT: COPY rls_test_tgt, line 1: "1,tgt a"

This "missing data for column c" error is actually a COPY formatting error, not an RLS policy violation.

Best regards,

--

Yilin Zhang