Fix estimate_array_length error with set-operation array coercions When a nested set operation's output type doesn't match the parent's expected type, recurse_set_operations builds a projection target list using generate_setop_tlist with varno 0. If the required type coercion involves an ArrayCoerceExpr, estimate_array_length could be called on such a Var, and would pass it to examine_variable, which errors in find_base_rel because varno 0 has no valid relation entry.
Fix by skipping the statistics lookup for Vars with varno 0. Bug introduced by commit 9391f7152. Back-patch to v17, where estimate_array_length was taught to use statistics. Reported-by: Justin Pryzby <[email protected]> Author: Tender Wang <[email protected]> Reviewed-by: Richard Guo <[email protected]> Discussion: https://postgr.es/m/adjW8rfPDkplC7lF@pryzbyj2023 Backpatch-through: 17 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/77d0e82e58854cfa5e2c4f365a97f16c0d91c394 Modified Files -------------- src/backend/utils/adt/selfuncs.c | 12 ++++++++++++ src/test/regress/expected/union.out | 17 +++++++++++++++++ src/test/regress/sql/union.sql | 4 ++++ 3 files changed, 33 insertions(+)
