<div dir="ltr">One of the queries in ri_triggers.c has be a little baffled.<br /><br />For (relatively) obvious
reasons,a FK insert triggers a SELECT 1 FROM pk_rel ... FOR KEY SHARE.<br />For not-so-obvious reasons, a PK delete
triggersa SELECT 1 FROM fk_rel ... FOR KEY SHARE.<br /><br />I can't see what the lock on fk_rel achieves. Both
operationsare already contending for the lock on the PK row, which seems like enough to cover every eventuality.<br
/><br/>And even if the lock serves a purpose, KEY SHARE is an odd choice, since the referencing field is, in general,
nota "key" in this sense.<br /><br />Can anyone provide an explanation / counterexample?<br /></div>
