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.
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.
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...
New patch attached. It also removes some other unstable output from the
regression test.
--
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
index d2175d5..d5c576d 100644
--- a/doc/src/sgml/pltcl.sgml
+++ b/doc/src/sgml/pltcl.sgml
@@ -775,6 +775,127 @@ CREATE EVENT TRIGGER tcl_a_snitch ON ddl_command_start
EXECUTE PROCEDURE tclsnit
</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
index e11718c..0592c48 100644
--- a/src/pl/tcl/expected/pltcl_setup.out
+++ b/src/pl/tcl/expected/pltcl_setup.out
@@ -555,3 +555,51 @@ NOTICE: tclsnitch: ddl_command_start DROP TABLE
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
index 5b27c73..d8a8a89 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -1576,6 +1576,98 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
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
@@ -1610,6 +1702,8 @@ pltcl_elog(ClientData cdata, Tcl_Interp *interp,
level = loglevels[priIndex];
+ level = loglevels[priIndex];
+
if (level == ERROR)
{
/*
@@ -1652,6 +1746,7 @@ pltcl_elog(ClientData cdata, Tcl_Interp *interp,
UTF_BEGIN;
Tcl_SetObjResult(interp,
Tcl_NewStringObj(UTF_E2U(edata->message), -1));
UTF_END;
+ pltcl_construct_errorCode(interp, edata);
FreeErrorData(edata);
return TCL_ERROR;
@@ -1884,6 +1979,7 @@ pltcl_subtrans_abort(Tcl_Interp *interp,
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
index 53358ea..3ee8583 100644
--- a/src/pl/tcl/sql/pltcl_setup.sql
+++ b/src/pl/tcl/sql/pltcl_setup.sql
@@ -595,3 +595,29 @@ drop table foo;
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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