Re: [GENERAL] DECLARE CURSOR - Mailing list pgsql-hackers

Hello, is it planed cursor out of a transaction in 7.4 ?
Thanks
Haris Peco
On Monday 18 November 2002 12:30 am, Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Let's just fix it and roll an RC2 with the fix.  If not, we can just fix
> > it in 7.3.1 but I see little problem in rolling an RC2.
>
> Here is the patch I am testing (in current sources; I don't think it
> needs any adjustments for REL7_3, but haven't tried to apply it yet).
> Basically it moves the test that was originally done in parse/analyze.c
> into the execution-time setup of a cursor, and enlarges the test to
> understand about autocommit-off and inside-a-function exceptions.
> Anyone see a problem?
>
>             regards, tom lane
>
> *** src/backend/access/transam/xact.c.orig    Wed Nov 13 10:51:46 2002
> --- src/backend/access/transam/xact.c    Sun Nov 17 19:10:20 2002
> ***************
> *** 1488,1493 ****
> --- 1488,1537 ----
>       }
>   }
>
> + /* --------------------------------
> +  *    RequireTransactionChain
> +  *
> +  *    This routine is to be called by statements that must run inside
> +  *    a transaction block, because they have no effects that persist past
> +  *    transaction end (and so calling them outside a transaction block
> +  *    is presumably an error).  DECLARE CURSOR is an example.
> +  *
> +  *    If we appear to be running inside a user-defined function, we do not
> +  *    issue an error, since the function could issue more commands that make
> +  *    use of the current statement's results.  Thus this is an inverse for
> +  *    PreventTransactionChain.
> +  *
> +  *    stmtNode: pointer to parameter block for statement; this is used in
> +  *    a very klugy way to determine whether we are inside a function.
> +  *    stmtType: statement type name for error messages.
> +  * --------------------------------
> +  */
> + void
> + RequireTransactionChain(void *stmtNode, const char *stmtType)
> + {
> +     /*
> +      * xact block already started?
> +      */
> +     if (IsTransactionBlock())
> +         return;
> +     /*
> +      * Are we inside a function call?  If the statement's parameter block
> +      * was allocated in QueryContext, assume it is an interactive command.
> +      * Otherwise assume it is coming from a function.
> +      */
> +     if (!MemoryContextContains(QueryContext, stmtNode))
> +         return;
> +     /*
> +      * If we are in autocommit-off mode then it's okay, because this
> +      * statement will itself start a transaction block.
> +      */
> +     if (!autocommit && !suppressChain)
> +         return;
> +     /* translator: %s represents an SQL statement name */
> +     elog(ERROR, "%s may only be used in begin/end transaction blocks",
> +          stmtType);
> + }
> +
>
>   /* ----------------------------------------------------------------
>    *                       transaction block support
> *** /home/postgres/pgsql/src/backend/tcop/pquery.c.orig    Wed Sep  4 17:30:43
> 2002 --- /home/postgres/pgsql/src/backend/tcop/pquery.c    Sun Nov 17 19:10:26
> 2002 ***************
> *** 161,166 ****
> --- 161,168 ----
>               /* If binary portal, switch to alternate output format */
>               if (dest == Remote && parsetree->isBinary)
>                   dest = RemoteInternal;
> +             /* Check for invalid context (must be in transaction block) */
> +             RequireTransactionChain((void *) parsetree, "DECLARE CURSOR");
>           }
>           else if (parsetree->into != NULL)
>           {
> *** /home/postgres/pgsql/src/include/access/xact.h.orig    Wed Nov 13 10:52:07
> 2002 --- /home/postgres/pgsql/src/include/access/xact.h    Sun Nov 17 19:10:13
> 2002 ***************
> *** 115,120 ****
> --- 115,121 ----
>   extern void UserAbortTransactionBlock(void);
>   extern void AbortOutOfAnyTransaction(void);
>   extern void PreventTransactionChain(void *stmtNode, const char
> *stmtType); + extern void RequireTransactionChain(void *stmtNode, const
> char *stmtType);
>
>   extern void RecordTransactionCommit(void);
>
>
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