refint: Remove plan cache. Presently, refint stores plans in a per-backend cache to avoid re-preparing in each call. This has a few problems. For one, check_foreign_key() embeds the new key values in its cascade-UPDATE queries, so a cached plan reuses the values from preparation. Also, the cache is never invalidated, so it can return stale entries that cause other problems. There may very well be more bugs lurking.
We could spend a lot of time trying to address all these problems, but this module is primarily intended as sample code, and by all indications, it sees minimal use. Furthermore, there is a growing consensus for removing refint in v20. However, since we'll need to support it on the back-branches for a while longer, it probably still makes sense to fix some of the more egregious bugs. Therefore, let's just remove refint's plan cache entirely. That means we'll re-prepare on every call, but that seems quite unlikely to bother anyone. On v17 and older versions, the regression test for triggers fails after this change, so I've borrowed pieces of commit 8cfbdf8f4d to fix it. Author: Ayush Tiwari <[email protected]> Discussion: https://postgr.es/m/CAJTYsWXU%2BfhuzrEd_bnrxyGH3%2Bny8QRQC2QHf3ws6s9iki3c2Q%40mail.gmail.com Backpatch-through: 14 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/a572dd213f79898ad6ca66ac9d8b0912040e6691 Modified Files -------------- contrib/spi/refint.c | 352 +++++++++++---------------------- src/test/regress/expected/triggers.out | 37 ++-- src/test/regress/sql/triggers.sql | 10 +- 3 files changed, 138 insertions(+), 261 deletions(-)
