pgbk: ensure TOASTed values in the change feed#29965
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espadolini merged 1 commit intomasterfrom Aug 3, 2023
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This PR makes it so that we forcibly update values during
KeepAlive, because unchanged TOASTed values are not stored in the WAL, even at logical level. This can happen when doingKeepAliveon anodewith a lot of labels, for example.This relies on the planner not being able to see that we are not going to be actually mutating the value; from my tests it seems to work even with a literal
value = value || ''but we go the extra mile and actually send an always-empty bytestring to concatenate to.A more stable solution might be to switch to
REPLICA IDENTITY FULLon the table, but that requires some smarter parsing of the change feed data and comes with some performance drawbacks (as the WAL essentially doubles in volume).Fixes #29911.