Make rewriter prevent auto-updates on views with conditional INSTEAD rules.
A view with conditional INSTEAD rules and no unconditional INSTEAD
rules or INSTEAD OF triggers is not auto-updatable. Previously we
relied on a check in the executor to catch this, but that's
problematic since the planner may fail to properly handle such a query
and thus return a particularly unhelpful error to the user, before
reaching the executor check.
Instead, trap this in the rewriter and report the correct error there.
Doing so also allows us to include more useful error detail than the
executor check can provide. This doesn't change the existing behaviour
of updatable views; it merely ensures that useful error messages are
reported when a view isn't updatable.
Per report from Pengzhou Tang, though not adopting that suggested fix.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/CAG4reAQn+4xB6xHJqWdtE0ve_WqJkdyCV4P=trYr4Kn8_3_PEA@mail.gmail.com
Branch
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REL9_5_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/bb09a9414f1e149aac6064d217b5d5cab8f13723
Modified Files
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src/backend/executor/execMain.c | 8 ++--
src/backend/rewrite/rewriteHandler.c | 60 ++++++++++++++++++++++++---
src/test/regress/expected/updatable_views.out | 21 ++++++++++
src/test/regress/sql/updatable_views.sql | 14 +++++++
4 files changed, 94 insertions(+), 9 deletions(-)