There was no reason I needed to run full statements in this case. I just didn't know I could get the type ids like that.
Thanks for all of your help Andres! On Tue, Feb 10, 2015 at 1:23 PM, Andres Freund <and...@2ndquadrant.com> wrote: > On 2015-02-10 10:33:41 -0800, Xavier Stevens wrote: > > Sorry to raise the issue on startup_cb. I added a whole bunch of logging > > statements and I was only running the section of code I wanted when the > > startup callback had options. > > Heh. > > Just to make sure: You can pass options via replication protocol too. > > > This now gets me to the next issue I encounter. In my output plugin, I'm > > trying to use the SPI interface to query about PostGIS OIDs in the > startup > > callback. Just calling SPI_connect() seems to be causing a segfault. > > > This is the last thing I see in the logs before the segfault occurs: > > > > > https://github.com/xstevens/decoderbufs/blob/master/src/decoderbufs.c#L151 > > The problem likely is that in the startup callback you're neither > guaranteed to be in a transaction, nor to have a snapshot set up. > > It'd generally be easier to analyze such problems if you provide a > backtrace (e.g. by enabling core files). Another generally very > adviseable thing to do when developing code running in the backend is to > enable assertions (you may already do that...). > > You can lookup types much easier than that btw. C.f. > TypenameGetTypid(typname) > > But note that both that and what you do would possibly fail if there's > more than one geometry type around. You could either hardcode postgis' > schema name and use > namespaceId = LookupExplicitNamespace(schemaname, false); > typoid = GetSysCacheOid2(TYPENAMENSP, PointerGetDatum(typname), > ObjectIdGetDatum(namespaceId)); > if (typoid == InvalidOid) > elog(ERROR, "cache lookup failed for type %u", typoid); > > or be a bit more complex and lookup the postgis' extension's schema > pg_extension.extnamespace first. > > > Anyway, to run full queries in the startup callback you're going to have > to do something like: > > if (!IsTransactionState()) > { > tx_started = true; > StartTransactionCommand(); > } > PushActiveSnapshot(GetTransactionSnapshot()); > > /* do your stuff */ > > PopActiveSnapshot(); > if (tx_started) > CommitTransactionCommand(); > > > Note that the begin, change, commit callbacks *do* run with a > transaction and snapshot setup. But you can't run general SQL queries - > only catalog tables (or tables marked as such) are accessible. > > Greetings, > > Andres Freund > > -- > Andres Freund http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services >
