pgsql: Support PlaceHolderVars in MERGE actions.

2023-03-15 Thread Tom Lane
Support PlaceHolderVars in MERGE actions. preprocess_targetlist thought PHVs couldn't appear here. It was mistaken, as per report from Önder Kalacı. Surveying other pull_var_clause calls, I noted no similar errors, but I did notice that qual_is_pushdown_safe's assertion about !contain_window_func

pgsql: Support PlaceHolderVars in MERGE actions.

2023-03-15 Thread Tom Lane
Support PlaceHolderVars in MERGE actions. preprocess_targetlist thought PHVs couldn't appear here. It was mistaken, as per report from Önder Kalacı. Surveying other pull_var_clause calls, I noted no similar errors, but I did notice that qual_is_pushdown_safe's assertion about !contain_window_func