mirror of
https://github.com/postgres/postgres.git
synced 2025-11-22 00:10:07 -05:00
0b5c161248
5ae2087202 implemented a cross-page unique constraint check by loading the right sibling to the BtreeCheckState.target variable. This is wrong, because bt_target_page_check() shouldn't change the target page. Also, BtreeCheckState.target shouldn't be changed alone without BtreeCheckState.targetblock. However, the above didn't cause any visible bugs for the following reasons. 1. We do a cross-page unique constraint check only for leaf index pages. 2. The only way target page get accessed after a cross-page unique constraint check is loading of the lowkey. 3. The only place lowkey is used is bt_child_highkey_check(), and that applies only to non-leafs. The reasons above don't diminish the fact that changing BtreeCheckState.target for a cross-page unique constraint check is wrong. This commit changes this check to temporarily store the right sibling to the local variable. Reported-by: Peter Geoghegan Discussion: https://postgr.es/m/CAH2-Wzk%2B2116uOXdOViA27SHcr31WKPgmjsxXLBs_aTxAeThzg%40mail.gmail.com Author: Pavel Borisov