On Wed, May 17, 2017 at 5:17 PM, Robert Haas <robertmhaas@gmail.com> wrote: > On Wed, May 17, 2017 at 6:29 AM, Amit Kapila <amit.kapila16@gmail.com> wrote: >> I think we can do this even without using an additional infomask bit. >> As suggested by Greg up thread, we can set InvalidBlockId in ctid to >> indicate such an update. > > Hmm. How would that work? >
We can pass a flag say row_moved (or require_row_movement) to heap_delete which will in turn set InvalidBlockId in ctid instead of setting it to self. Then the ExecUpdate needs to check for the same and return an error when heap_update is not successful (result != HeapTupleMayBeUpdated). Can you explain what difficulty are you envisioning?
Attaching WIP patch incorporates the above logic, although I am yet to check
all the code for places which might be using ip_blkid. I have got a small query here,
do we need an error on HeapTupleSelfUpdated case as well?
Note that patch should be applied to the top of Amit Khandekar's latest patch(v17_rebased).
