From: | Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com> |
---|---|
To: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Doubt about boundParams |
Date: | 2011-08-02 09:54:21 |
Message-ID: | CAFjFpRe36ZBZ-vEZxFYC+_b5acj74-2xyuWamAaqsNkHJz13dQ@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Hi All,
I am looking at usage of bound parameters.
In functions SPI_cursor_open_with_args() and SPI_cursor_open_with_args()
parameters are flagged as constants and passed to the planner in following
manner,
paramLI = _SPI_convert_params(nargs, argtypes,
Values, Nulls,
PARAM_FLAG_CONST);
_SPI_prepare_plan(src, &plan, paramLI);
The bound params "paramLI" are then passed to the planner as boundParams.
Before actually planning the query, these parameters are evaluated duing
constant evaluation (eval_const_expressions_mutator()), and the Param nodes
are replaced with Constant nodes.
Further, while executing such queries we pass the paramLI structure to the
execution routine e.g. _SPI_execute_plan(). These parameter values are
stored in "EState" structure. But, since these parameters are already folded
into queries, it looks like parameter values stored in EState are never
used.
Is this correct? Or somewhere we use those parameter values?
--
Best Wishes,
Ashutosh Bapat
EntepriseDB Corporation
The Enterprise Postgres Company
From | Date | Subject | |
---|---|---|---|
Next Message | Heikki Linnakangas | 2011-08-02 10:15:48 | Re: Doubt about boundParams |
Previous Message | Florian Pflug | 2011-08-02 08:33:39 | Re: WIP fix proposal for bug #6123 |