Hi
2016-03-13 20:24 GMT+01:00 Jim Nasby <[email protected]>:
> On 3/3/16 8:51 AM, Pavel Stehule wrote:
>
>> Hi
>>
>> I am testing behave, and some results looks strange
>>
>
> Thanks for the review!
>
> postgres=# \sf foo
>> CREATE OR REPLACE FUNCTION public.foo()
>> RETURNS void
>> LANGUAGE plpgsql
>> AS $function$
>> begin
>> raise exception sqlstate 'ZZ666' using message='hello, world',
>> detail='hello, my world', hint = 'dont afraid';
>> end
>> $function$
>>
>> postgres=# select tcl_eval('spi_exec "select foo();"');
>> ERROR: 38000: hello, world
>> CONTEXT: hello, world <<<<==========???????
>>
>> the message was in context. Probably it is out of scope of this patch,
>> but it isn't consistent with other PL
>>
>>
>> while executing
>> "spi_exec "select foo();""
>> ("eval" body line 1)
>> invoked from within
>> "eval $1"
>> (procedure "__PLTcl_proc_16864" line 3)
>> invoked from within
>> "__PLTcl_proc_16864 {spi_exec "select foo();"}"
>> in PL/Tcl function "tcl_eval"
>> LOCATION: throw_tcl_error, pltcl.c:1217
>> Time: 1.178 ms
>>
>
> Both problems actually exists in HEAD. The issue is this line in
> throw_tcl_error:
>
> econtext = utf_u2e(Tcl_GetVar(interp, "errorInfo",
> TCL_GLOBAL_ONLY));
>
> Offhand I don't see any great way to improve that behavior, and in any
> case it seems out of scope for this patch. As a workaround I'm just forcing
> psql error VERBOSITY to terse for now.
>
I understand - it is unpleasant, but it is another scope.
>
> postgres=# select tcl_eval('join $::errorCode "\n"');
>> tcl_eval
>> ═════════════════════════════════════════
>> POSTGRES ↵
>> message ↵
>> hello, world ↵
>> detail ↵
>> hello, my world ↵
>> hint ↵
>> dont afraid ↵
>> domain ↵
>> plpgsql-9.6 ↵
>> context_domain ↵
>> postgres-9.6 ↵
>> context ↵
>> PL/pgSQL function foo() line 3 at RAISE↵
>> SQL statement "select foo();" ↵
>> cursor_position ↵
>> 0 ↵
>> filename ↵
>> pl_exec.c ↵
>> lineno ↵
>> 3165 ↵
>> funcname ↵
>> exec_stmt_raise
>> (1 row)
>>
>> I miss a SQLSTATE.
>>
>
> Great catch. Fixed.
>
I can verify it. The doc should be updated too.
>
> Why is used List object instead dictionary? TCL supports it
>> https://www.tcl.tk/man/tcl8.5/tutorial/Tcl23a.html
>>
>
> Because errorCode unfortunately is an array and not a dict. It doesn't
> really seem worth messing with it in the eval since this is just a sanity
> check...
>
I am sorry, my I expected so we introduced errorCode. My question was not
valid
> New patch attached. It also removes some other unstable output from the
> regression test.
>
I checked this patch:
* This patch is relative trivial without any controversy - allow a access
to ErrorData fields is good idea, and we do it in some other PL longer time.
* There are no problem with patching, compiling
* all tests was passed
* a comments in code are adequate to low complexity
* code respects PostgreSQL formatting
* attached documentation is good and correct
* regress tests are adequate
I fixed the documentation - there was not information about SQLSTATE field.
See, please, attachment.
I'll mark this patch as ready for commiters.
Regards
Pavel
> --
> Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
> Experts in Analytics, Data Architecture and PostgreSQL
> Data in Trouble? Get it in Treble! http://BlueTreble.com
>
diff --git a/doc/src/sgml/pltcl.sgml b/doc/src/sgml/pltcl.sgml
new file mode 100644
index d2175d5..1ac7804
*** a/doc/src/sgml/pltcl.sgml
--- b/doc/src/sgml/pltcl.sgml
*************** CREATE EVENT TRIGGER tcl_a_snitch ON ddl
*** 775,780 ****
--- 775,903 ----
</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>SQLSTATE</varname>,
+ <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 +
+ SQLSTATE +
+ 42P01 +
+ 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..0592c48
*** a/src/pl/tcl/expected/pltcl_setup.out
--- b/src/pl/tcl/expected/pltcl_setup.out
*************** NOTICE: tclsnitch: ddl_command_start DR
*** 555,557 ****
--- 555,605 ----
NOTICE: tclsnitch: ddl_command_end DROP TABLE
drop event trigger tcl_a_snitch;
drop event trigger tcl_b_snitch;
+ -- test error handling
+ /*
+ * The ugly hack of messsing with the verbosity is because the error context is
+ * set to the TCL variable errorInfo, which contains some unstable data (namely
+ * the full name of the TCL function created by the handler, which includes the
+ * Postgres backend PID).
+ */
+ \set VERBOSITY terse
+ 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
+ select pg_temp.tcl_eval($$
+ set list [lindex $::errorCode 0];
+ foreach "key value" [lrange $::errorCode 1 end] {
+ if {$key == "domain" || $key == "context_domain" || $key == "lineno"} {
+ regsub -all {[0-9]} $value "" value
+ }
+ lappend list $key $value
+ };
+ return [join $list "\n"]
+ $$);
+ tcl_eval
+ -------------------------------
+ POSTGRES +
+ SQLSTATE +
+ 42P01 +
+ message +
+ relation "foo" does not exist+
+ domain +
+ postgres-. +
+ context_domain +
+ postgres-. +
+ cursor_position +
+ 0 +
+ internalquery +
+ select * from foo; +
+ internal_position +
+ 15 +
+ filename +
+ parse_relation.c +
+ lineno +
+ +
+ funcname +
+ parserOpenTable
+ (1 row)
+
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
new file mode 100644
index 5b27c73..d8a8a89
*** a/src/pl/tcl/pltcl.c
--- b/src/pl/tcl/pltcl.c
*************** compile_pltcl_function(Oid fn_oid, Oid t
*** 1576,1581 ****
--- 1576,1673 ----
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("SQLSTATE", -1));
+ Tcl_ListObjAppendElement(interp, obj, Tcl_NewStringObj(unpack_sql_state(edata->sqlerrcode), -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
*** 1610,1615 ****
--- 1702,1709 ----
level = loglevels[priIndex];
+ level = loglevels[priIndex];
+
if (level == ERROR)
{
/*
*************** pltcl_elog(ClientData cdata, Tcl_Interp
*** 1652,1657 ****
--- 1746,1752 ----
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 ****
--- 1979,1985 ----
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..3ee8583
*** a/src/pl/tcl/sql/pltcl_setup.sql
--- b/src/pl/tcl/sql/pltcl_setup.sql
*************** drop table foo;
*** 595,597 ****
--- 595,623 ----
drop event trigger tcl_a_snitch;
drop event trigger tcl_b_snitch;
+
+
+ -- test error handling
+
+ /*
+ * The ugly hack of messsing with the verbosity is because the error context is
+ * set to the TCL variable errorInfo, which contains some unstable data (namely
+ * the full name of the TCL function created by the handler, which includes the
+ * Postgres backend PID).
+ */
+ \set VERBOSITY terse
+ 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($$
+ set list [lindex $::errorCode 0];
+ foreach "key value" [lrange $::errorCode 1 end] {
+ if {$key == "domain" || $key == "context_domain" || $key == "lineno"} {
+ regsub -all {[0-9]} $value "" value
+ }
+ lappend list $key $value
+ };
+ return [join $list "\n"]
+ $$);
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