Greetings, Subject pretty much says it all. I've put up with this error in the past when it has caused me trouble but it's now starting to hit our clients on occation which is just unacceptable.
The way I've seen it happen, and this is just empirically so I'm not sure that it's exactly right, is something like this: Running with pg_autovacuum on the system Run a long-running PL/PgSQL function which creates tables Wait for some sort of overlap, and the PL/PgSQL function dies with the above error. I've also seen it happen when I've got a long-running PL/PgSQL function going and I'm creating tables in another back-end. From a prior discussion I *think* the issue is the lack of versioning/visibility information in the SysCache which means that if the long-running function attempts to look-up data about a table which was created *after* the long-running function started but was put into the common SysCache by another backend, the long-running function gets screwed by the 'tuple concurrently updated' query and ends up failing and being rolled back. If this is correct then the solution seems to be either add versioning to the SysCache data, or have an overall 'this SysCache is only good for data past transaction X' so that a backend which is prior to that version could just accept that it can't use the SysCache and fall back to accessing the data directly (if that's possible). I'm not very familiar with the way the SysCache system is envisioned but I'm not a terrible programmer (imv anyway) and given some direction on the correct approach to solving this problem I'd be happy to spend some time working on it. I'd *really* like to see this error just go away completely for all non-broken use-cases. Thanks, Stephen
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