Hi
2016-03-01 22:23 GMT+01:00 Jim Nasby <[email protected]>:
> On 2/29/16 10:01 PM, Tom Lane wrote:
>
>> Jim Nasby <[email protected]> writes:
>>
>>> On 2/28/16 5:50 PM, Jim Nasby wrote:
>>>
>>>> Per discussion in [1], this patch improves error reporting in pltcl.
>>>>
>>>
>> I forgot to mention that this work is sponsored by Flight Aware
>>> (http://flightaware.com).
>>>
>>
>> Huh ... I use that site. There's PG and pltcl code behind it?
>> Cool!
>>
>
>
I didn't study this patch deeper yet. Just I am sending rebased code
I found one issue. The context
+ ERROR: relation "foo" does not exist
+ CONTEXT: relation "foo" does not exist
+ while executing
+ "spi_exec "select * from foo;""
+ ("eval" body line 1)
+ invoked from within
+ "eval $1"
+ (procedure "__PLTcl_proc_16461" line 3)
+ invoked from within
+ "__PLTcl_proc_16461 {spi_exec "select * from foo;"}"
+ in PL/Tcl function "tcl_eval"
is changed in any call - when I did "make installcheck"
*** 567,575 ****
("eval" body line 1)
invoked from within
"eval $1"
! (procedure "__PLTcl_proc_16461" line 3)
invoked from within
! "__PLTcl_proc_16461 {spi_exec "select * from foo;"}"
in PL/Tcl function "tcl_eval"
select pg_temp.tcl_eval($$
set list [lindex $::errorCode 0];
--- 567,575 ----
("eval" body line 1)
invoked from within
"eval $1"
! (procedure "__PLTcl_proc_16841" line 3) <<<<<====================
_PLTcl_proc_XXXX
invoked from within
! "__PLTcl_proc_16841 {spi_exec "select * from foo;"}"
in PL/Tcl function "tcl_eval"
select pg_temp.tcl_eval($$
set list [lindex $::errorCode 0];
I am not able to see, if this information is interesting or not. We can
hide context, but I have not a idea, if it is ok or not.
Regards
Pavel
diff --git a/doc/src/sgml/pltcl.sgml b/doc/src/sgml/pltcl.sgml
new file mode 100644
index d2175d5..d5c576d
*** a/doc/src/sgml/pltcl.sgml
--- b/doc/src/sgml/pltcl.sgml
*************** CREATE EVENT TRIGGER tcl_a_snitch ON ddl
*** 775,780 ****
--- 775,901 ----
</para>
</sect1>
+ <sect1 id="pltcl-error-handling">
+ <title>Error Handling in PL/Tcl</title>
+
+ <indexterm>
+ <primary>error handling</primary>
+ <secondary>in PL/Tcl</secondary>
+ </indexterm>
+
+ <para>
+ All Tcl errors that are allowed to propagate back to the top level of the
+ interpreter, that is, errors not caught within the stored procedure
+ using the Tcl <function>catch</function> command will raise a database
+ error.
+ </para>
+ <para>
+ Tcl code within or called from the stored procedure can choose to
+ raise a database error by invoking the <function>elog</function>
+ command provided by PL/Tcl or by generating an error using the Tcl
+ <function>error</function> command and not catching it with Tcl's
+ <function>catch</function> command.
+ </para>
+ <para>
+ Database errors that occur from the PL/Tcl stored procedure's
+ use of <function>spi_exec</function>, <function>spi_prepare</function>,
+ and <function>spi_execp</function> are also catchable by Tcl's
+ <function>catch</function> command.
+ </para>
+ <para>
+ Tcl provides an <varname>errorCode</varname> variable that can
+ represent additional information about the error in a form that
+ is easy for programs to interpret. The contents are in Tcl list
+ format and the first word identifies the subsystem or
+ library responsible for the error and beyond that the contents are left
+ to the individual code or library. For example if Tcl's
+ <function>open</function> command is asked to open a file that doesn't
+ exist, <varname>errorCode</varname>
+ might contain <literal>POSIX ENOENT {no such file or directory}</literal>
+ where the third element may vary by locale but the first and second
+ will not.
+ </para>
+ <para>
+ When <function>spi_exec</function>, <function>spi_prepare</function>
+ or <function>spi_execp</function> cause a database error to be raised,
+ that database eror propagates back to Tcl as a Tcl error.
+ In this case <varname>errorCode</varname> is set to a list
+ where the first element is <literal>POSTGRES</literal> followed by a
+ copious decoding of the Postgres error structure. Since fields in the
+ structure may or may not be present depending on the nature of the
+ error, how the function was invoked, etc, PL/Tcl has adopted the
+ convention that subsequent elements of the <varname>errorCode</varname>
+ list are key-value pairs where the first value is the name of the
+ field and the second is its value.
+ </para>
+ <para>
+ Fields that may be present include <varname>message</varname>,
+ <varname>detail</varname>, <varname>detail_log</varname>,
+ <varname>hint</varname>, <varname>domain</varname>,
+ <varname>context_domain</varname>, <varname>context</varname>,
+ <varname>schema</varname>, <varname>table</varname>,
+ <varname>column</varname>, <varname>datatype</varname>,
+ <varname>constraint</varname>, <varname>cursor_position</varname>,
+ <varname>internalquery</varname>, <varname>internal_position</varname>,
+ <varname>filename</varname>, <varname>lineno</varname> and
+ <varname>funcname</varname>.
+ </para>
+ <para>
+ You might find it useful to load the results into an array. Code
+ for doing that might look like
+ <programlisting>
+ if {[lindex $errorCode 0] == "POSTGRES"} {
+ array set errorRow [lrange $errorCode 1 end]
+ }
+ </programlisting>
+ </para>
+ <para>
+ In the example below we cause an error by attempting to
+ <command>SELECT</> from a table that doesn't exist.
+ <screen>
+ select tcl_eval('spi_exec "select * from foo;"');
+ </screen>
+ <screen>
+ <computeroutput>
+ ERROR: relation "foo" does not exist
+ </computeroutput>
+ </screen>
+ </para>
+ <para>
+ Now we examine the error code. (The double-colons explicitly
+ reference <varname>errorCode</varname> as a global variable.)
+ <screen>
+ select tcl_eval('join $::errorCode "\n"');
+ </screen>
+ <screen>
+ <computeroutput>
+ tcl_eval
+ -------------------------------
+ POSTGRES +
+ message +
+ relation "foo" does not exist+
+ domain +
+ postgres-9.6 +
+ context_domain +
+ postgres-9.6 +
+ cursorpos +
+ 0 +
+ internalquery +
+ select * from foo; +
+ internalpos +
+ 15 +
+ filename +
+ parse_relation.c +
+ lineno +
+ 1159 +
+ funcname +
+ parserOpenTable
+ (1 row)
+ </computeroutput>
+ </screen>
+ </para>
+ </sect1>
+
<sect1 id="pltcl-unknown">
<title>Modules and the <function>unknown</> Command</title>
<para>
diff --git a/src/pl/tcl/expected/pltcl_setup.out b/src/pl/tcl/expected/pltcl_setup.out
new file mode 100644
index e11718c..cac7597
*** a/src/pl/tcl/expected/pltcl_setup.out
--- b/src/pl/tcl/expected/pltcl_setup.out
*************** NOTICE: tclsnitch: ddl_command_start DR
*** 555,557 ****
--- 555,598 ----
NOTICE: tclsnitch: ddl_command_end DROP TABLE
drop event trigger tcl_a_snitch;
drop event trigger tcl_b_snitch;
+ -- test error handling
+ CREATE OR REPLACE FUNCTION pg_temp.tcl_eval (varchar) RETURNS varchar AS $$
+ eval $1
+ $$ LANGUAGE pltcl;
+ select pg_temp.tcl_eval('spi_exec "select * from foo;"');
+ ERROR: relation "foo" does not exist
+ CONTEXT: relation "foo" does not exist
+ while executing
+ "spi_exec "select * from foo;""
+ ("eval" body line 1)
+ invoked from within
+ "eval $1"
+ (procedure "__PLTcl_proc_16461" line 3)
+ invoked from within
+ "__PLTcl_proc_16461 {spi_exec "select * from foo;"}"
+ in PL/Tcl function "tcl_eval"
+ select pg_temp.tcl_eval($$
+ set list [lindex $::errorCode 0];
+ foreach "key value" [lrange $::errorCode 1 end] {
+ if {$key == "domain" || $key == "context_domain" || $key == "lineno"} continue;
+ lappend list $key $value
+ };
+ return [join $list "\n"]
+ $$);
+ tcl_eval
+ -------------------------------
+ POSTGRES +
+ message +
+ relation "foo" does not exist+
+ cursor_position +
+ 0 +
+ internalquery +
+ select * from foo; +
+ internal_position +
+ 15 +
+ filename +
+ parse_relation.c +
+ funcname +
+ parserOpenTable
+ (1 row)
+
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
new file mode 100644
index 105b618..7e064d9
*** a/src/pl/tcl/pltcl.c
--- b/src/pl/tcl/pltcl.c
*************** static int pltcl_SPI_lastoid(ClientData
*** 237,242 ****
--- 237,243 ----
static void pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
int tupno, HeapTuple tuple, TupleDesc tupdesc);
static Tcl_Obj *pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc);
+ static void pltcl_construct_errorCode(Tcl_Interp *interp, ErrorData *edata);
/*
*************** compile_pltcl_function(Oid fn_oid, Oid t
*** 1576,1581 ****
--- 1577,1672 ----
return prodesc;
}
+ /**********************************************************************
+ * pltcl_construct_errorCode() - construct a Tcl errorCode
+ * list with detailed information from the PostgreSQL server
+ **********************************************************************/
+ static void
+ pltcl_construct_errorCode(Tcl_Interp *interp, ErrorData *edata)
+ {
+ Tcl_Obj *obj = Tcl_NewObj();
+
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("POSTGRES", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("message", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->message, -1));
+
+ if (edata->detail)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("detail", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->detail, -1));
+ }
+ if (edata->detail_log)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("detail_log", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->detail_log, -1));
+ }
+ if (edata->hint)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("hint", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->hint, -1));
+ }
+ if (edata->domain)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("domain", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->domain, -1));
+ }
+ if (edata->context_domain)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("context_domain", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->context_domain, -1));
+ }
+ if (edata->context)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("context", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->context, -1));
+ }
+ if (edata->schema_name)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("schema", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->schema_name, -1));
+ }
+ if (edata->table_name)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("table", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->table_name, -1));
+ }
+ if (edata->column_name)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("column", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->column_name, -1));
+ }
+ if (edata->datatype_name)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("datatype", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->datatype_name, -1));
+ }
+ if (edata->constraint_name)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("constraint", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->constraint_name, -1));
+ }
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("cursor_position", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewIntObj(edata->cursorpos));
+ if (edata->internalquery)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("internalquery", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->internalquery, -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("internal_position", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewIntObj(edata->internalpos));
+ }
+ if (edata->filename)
+ {
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("filename", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->filename, -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("lineno", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewIntObj(edata->lineno));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj("funcname", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(edata->funcname, -1));
+ }
+
+ Tcl_SetObjErrorCode(interp, obj);
+ }
+
/**********************************************************************
* pltcl_elog() - elog() support for PLTcl
*************** pltcl_elog(ClientData cdata, Tcl_Interp
*** 1652,1657 ****
--- 1743,1749 ----
UTF_BEGIN;
Tcl_SetObjResult(interp, Tcl_NewStringObj(UTF_E2U(edata->message), -1));
UTF_END;
+ pltcl_construct_errorCode(interp, edata);
FreeErrorData(edata);
return TCL_ERROR;
*************** pltcl_subtrans_abort(Tcl_Interp *interp,
*** 1884,1889 ****
--- 1976,1982 ----
UTF_BEGIN;
Tcl_SetResult(interp, UTF_E2U(edata->message), TCL_VOLATILE);
UTF_END;
+ pltcl_construct_errorCode(interp, edata);
FreeErrorData(edata);
}
diff --git a/src/pl/tcl/sql/pltcl_setup.sql b/src/pl/tcl/sql/pltcl_setup.sql
new file mode 100644
index 53358ea..ddc30c9
*** a/src/pl/tcl/sql/pltcl_setup.sql
--- b/src/pl/tcl/sql/pltcl_setup.sql
*************** drop table foo;
*** 595,597 ****
--- 595,613 ----
drop event trigger tcl_a_snitch;
drop event trigger tcl_b_snitch;
+
+
+ -- test error handling
+ CREATE OR REPLACE FUNCTION pg_temp.tcl_eval (varchar) RETURNS varchar AS $$
+ eval $1
+ $$ LANGUAGE pltcl;
+
+ select pg_temp.tcl_eval('spi_exec "select * from foo;"');
+ select pg_temp.tcl_eval($$
+ set list [lindex $::errorCode 0];
+ foreach "key value" [lrange $::errorCode 1 end] {
+ if {$key == "domain" || $key == "context_domain" || $key == "lineno"} continue;
+ lappend list $key $value
+ };
+ return [join $list "\n"]
+ $$);
--
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