Re: Preventing some SQL commands

James William Pye

>bool (*SPI_UtilityFilter) (NodeTag aStmt);
>To a "void SPI_FilterUtilities(void *execPlan, SPI_UtilityFilter fp)".
>
>Throwing an error if deemed necessary by the pointed to function.
>  
>
After browsing the code a bit more, I realize that the above suggestion 
is superior to my own. It doesn't require a memory allocation and it's 
very close to what I'd like to have. I'd like it a bit more generic to 
allow arbitrary perusal of Query attributes. Like this to be more precise:

typedef bool (*QueryVisitor)(Query* query, void *clientData);

bool
SPI_traverse_query_roots(void *plan, QueryVisitor queryVisitor, void* 
clientData)
{   List     *query_list_list = ((_SPI_plan*)plan)->qtlist;   ListCell *query_list_list_item;
   foreach(query_list_list_item, query_list_list)   {       List     *query_list = lfirst(query_list_list_item);
ListCell*query_list_item;
 
       foreach(query_list_item, query_list)       {           if(!queryVisitor((Query *)lfirst(query_list_item),
clientData))              return false;       }   }   return true;
 
}

This will allow me to implement a QueryVisitor like so:

static bool detectTransactCommands(Query* query, void* clientData)
{   return !(query->commandType == CMD_UTILITY &&           IsA(query->utilityStmt, TransactionStmt));
}

and then test using:

if(!SPI_traverse_query_roots(myPlan, detectTransactCommands, null))   /* Handle error here */

Any chance a patch containing the SPI_traverse_query_roots would be 
accepted?

Regards,
Thomas Hallgren