Hi, It seems that README.tuplock never got updated when the KEY SHARE patch's lock level were changed from being KEY UPDATE / UPDATE / SHARE / KEY SHARE to UPDATE / NO KEY UPDATE / SHARE / KEY SHARE.
Thus, as it stands, that file implies that SELECT FOR UPDATE obtains a weaker lock than an actual UPDATE might take (if that update modifies key columns) -- according to README.tuplock, the former doesn't conflict with KEY SHARE while the actual UPDATE would. But this isn't actually the case in the committed version of the patch - one now needs to explicitly request that weaker lock level with SELECT FOR NO KEY UPDATE. The attached patch updated README.tuplock accordingly. best regards, Florian Pflug
README.tuplock.patch
Description: Binary data
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