Re: Where to call SetQuerySnapshot

Tom Lane wrote:
> I did this and ended up with a rather long list of statement types that
> might need a snapshot:
>
> elog(DEBUG2, "ProcessUtility");
>
> /* set snapshot if utility stmt needs one */
> /* XXX maybe cleaner to list those that shouldn't set one? */
> if (IsA(utilityStmt, AlterTableStmt) ||
> IsA(utilityStmt, ClusterStmt) ||
> IsA(utilityStmt, CopyStmt) ||
> IsA(utilityStmt, ExecuteStmt) ||
> IsA(utilityStmt, ExplainStmt) ||
> IsA(utilityStmt, IndexStmt) ||
> IsA(utilityStmt, PrepareStmt) ||
> IsA(utilityStmt, ReindexStmt))
> SetQuerySnapshot();
>
> (Anything that can call the planner or might create entries in
> functional indexes had better set a snapshot, thus stuff like
> ReindexStmt has the issue.)
>
> I wonder if we should turn this around, and set a snapshot for all
> utility statements that can't show cause why they don't need one.
> Offhand, TransactionStmt, FetchStmt, and VariableSet/Show/Reset
> might be the only ones that need be excluded. Comments?

It looks like an exclusion list would be easier to read and maintain.

Joe