On Fri, Feb 25, 2022 at 06:39:39PM +0000, Chapman Flack wrote:
> This patch is straightforward, does what it says, and passes the tests.
>
> Regarding the duplication of code between plsample_func_handler and
> plsample_trigger_handler, perhaps that's for the best for now, as 3554 in
> the same commitfest also touches plsample, so merge conflicts may be
> minimized by not doing more invasive refactoring.
>
> That would leave low-hanging fruit for a later patch that could refactor
> plsample to reduce the duplication (maybe adding a validator at the same
> time? That would also duplicate some of the checks in the existing handlers.)
>
> I am not sure that structuring the trigger handler with separate compile and
> execute steps is worth the effort for a simple example like plsample. The main
> plsample_func_handler is not so structured.
>
> It's likely that many real PLs will have some notion of compilation separate
> from
> execution. But those will also have logic to do the compilation only once, and
> somewhere to cache the result of that for reuse across calls, and those kinds
> of
> details might make plsample's basic skeleton more complex than needed.
>
> I know that in just looking at expected/plsample.out, I was a little
> distracted by
> seeing multiple "compile" messages for the same trigger function in the same
> session and wondering why that was.
>
> So maybe it would be simpler and less distracting to assume that the PL
> targeted
> by plsample is one that just has a simple interpreter that works from the
> source text.
I've attached v2, which reduces the output:
* Removing the notices for the text body, and the "compile" message.
* Replaced the notice for "compile" message with a comment as a
placeholder for where a compiling code or checking a cache may go.
* Reducing the number of rows inserted into the table, thus reducing
the number of notice messages about which code path is taken.
I think that reduces the repetitiveness of the output...
Regards,
Mark
diff --git a/src/test/modules/plsample/expected/plsample.out
b/src/test/modules/plsample/expected/plsample.out
index a0c318b6df..a7912c7897 100644
--- a/src/test/modules/plsample/expected/plsample.out
+++ b/src/test/modules/plsample/expected/plsample.out
@@ -6,9 +6,6 @@ AS $$
Example of source with text result.
$$ LANGUAGE plsample;
SELECT plsample_result_text(1.23, 'abc', '{4, 5, 6}');
-NOTICE: source text of function "plsample_result_text":
- Example of source with text result.
-
NOTICE: argument: 0; name: a1; value: 1.23
NOTICE: argument: 1; name: a2; value: abc
NOTICE: argument: 2; name: a3; value: {4,5,6}
@@ -25,12 +22,57 @@ AS $$
Example of source with void result.
$$ LANGUAGE plsample;
SELECT plsample_result_void('{foo, bar, hoge}');
-NOTICE: source text of function "plsample_result_void":
- Example of source with void result.
-
NOTICE: argument: 0; name: a1; value: {foo,bar,hoge}
plsample_result_void
----------------------
(1 row)
+CREATE FUNCTION my_trigger_func() RETURNS trigger AS $$
+if TD_event == "INSERT"
+ return TD_NEW
+elseif TD_event == "UPDATE"
+ return TD_NEW
+else
+ return "OK"
+end
+$$ language plsample;
+CREATE TABLE my_table (num integer, description text);
+CREATE TRIGGER my_trigger_func BEFORE INSERT OR UPDATE ON my_table
+ FOR EACH ROW EXECUTE FUNCTION my_trigger_func();
+CREATE TRIGGER my_trigger_func2 AFTER INSERT OR UPDATE ON my_table
+ FOR EACH ROW EXECUTE FUNCTION my_trigger_func(8);
+INSERT INTO my_table (num, description)
+VALUES (1, 'first');
+NOTICE: trigger name: my_trigger_func
+NOTICE: trigger relation: my_table
+NOTICE: trigger relation schema: public
+NOTICE: triggered by INSERT
+NOTICE: triggered BEFORE
+NOTICE: triggered per row
+NOTICE: trigger name: my_trigger_func2
+NOTICE: trigger relation: my_table
+NOTICE: trigger relation schema: public
+NOTICE: triggered by INSERT
+NOTICE: triggered AFTER
+NOTICE: triggered per row
+NOTICE: trigger arg[0]: 8
+UPDATE my_table
+SET description = 'first, modified once'
+WHERE num = 1;
+NOTICE: trigger name: my_trigger_func
+NOTICE: trigger relation: my_table
+NOTICE: trigger relation schema: public
+NOTICE: triggered by UPDATE
+NOTICE: triggered BEFORE
+NOTICE: triggered per row
+NOTICE: trigger name: my_trigger_func2
+NOTICE: trigger relation: my_table
+NOTICE: trigger relation schema: public
+NOTICE: triggered by UPDATE
+NOTICE: triggered AFTER
+NOTICE: triggered per row
+NOTICE: trigger arg[0]: 8
+DROP TRIGGER my_trigger_func ON my_table;
+DROP TRIGGER my_trigger_func2 ON my_table;
+DROP FUNCTION my_trigger_func;
diff --git a/src/test/modules/plsample/plsample.c
b/src/test/modules/plsample/plsample.c
index 6fc33c728c..fea266f522 100644
--- a/src/test/modules/plsample/plsample.c
+++ b/src/test/modules/plsample/plsample.c
@@ -19,6 +19,7 @@
#include "catalog/pg_type.h"
#include "commands/event_trigger.h"
#include "commands/trigger.h"
+#include "executor/spi.h"
#include "funcapi.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
@@ -29,6 +30,7 @@ PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(plsample_call_handler);
static Datum plsample_func_handler(PG_FUNCTION_ARGS);
+static HeapTuple plsample_trigger_handler(PG_FUNCTION_ARGS);
/*
* Handle function, procedure, and trigger calls.
@@ -51,6 +53,7 @@ plsample_call_handler(PG_FUNCTION_ARGS)
* (TriggerData *) fcinfo->context includes the
information of the
* context.
*/
+ retval =
PointerGetDatum(plsample_trigger_handler(fcinfo));
}
else if (CALLED_AS_EVENT_TRIGGER(fcinfo))
{
@@ -119,9 +122,6 @@ plsample_func_handler(PG_FUNCTION_ARGS)
elog(ERROR, "could not find source text of function \"%s\"",
proname);
source = DatumGetCString(DirectFunctionCall1(textout, ret));
- ereport(NOTICE,
- (errmsg("source text of function \"%s\": %s",
- proname, source)));
/*
* Allocate a context that will hold all the Postgres data for the
@@ -185,3 +185,176 @@ plsample_func_handler(PG_FUNCTION_ARGS)
ret = InputFunctionCall(&result_in_func, source, result_typioparam, -1);
PG_RETURN_DATUM(ret);
}
+
+/*
+ * plsample_trigger_handler
+ *
+ * Function called by the call handler for trigger execution.
+ */
+static HeapTuple
+plsample_trigger_handler(PG_FUNCTION_ARGS)
+{
+ TriggerData *trigdata = (TriggerData *) fcinfo->context;
+ char *string;
+ volatile HeapTuple rettup;
+ HeapTuple pl_tuple;
+ Datum ret;
+ char *source;
+ bool isnull;
+ Form_pg_proc pl_struct;
+ char *proname;
+ int rc PG_USED_FOR_ASSERTS_ONLY;
+ MemoryContext proc_cxt = NULL;
+ MemoryContext old_cxt = NULL;
+ char *trigger_code = NULL;
+
+ /* Make sure this is being called from a trigger. */
+ if (!CALLED_AS_TRIGGER(fcinfo))
+ elog(ERROR, "not called by trigger manager");
+
+ /* Connect to the SPI manager */
+ if (SPI_connect() != SPI_OK_CONNECT)
+ elog(ERROR, "could not connect to SPI manager");
+
+ rc = SPI_register_trigger_data(trigdata);
+ Assert(rc >= 0);
+
+ /* Fetch the source text of the function. */
+ pl_tuple = SearchSysCache(PROCOID,
+
ObjectIdGetDatum(fcinfo->flinfo->fn_oid), 0, 0, 0);
+ if (!HeapTupleIsValid(pl_tuple))
+ elog(ERROR, "cache lookup failed for function %u",
+ fcinfo->flinfo->fn_oid);
+
+ /*
+ * Extract and print the source text of the function. This can be used
as
+ * a base for the function validation and execution.
+ */
+ pl_struct = (Form_pg_proc) GETSTRUCT(pl_tuple);
+ proname = pstrdup(NameStr(pl_struct->proname));
+ ret = SysCacheGetAttr(PROCOID, pl_tuple, Anum_pg_proc_prosrc, &isnull);
+ if (isnull)
+ elog(ERROR, "could not find source text of function \"%s\"",
+ proname);
+ source = DatumGetCString(DirectFunctionCall1(textout, ret));
+
+ PG_TRY();
+ {
+ char *internal_args = "TD_name, TD_relid, TD_table_name,
TD_table_schema, TD_event, TD_when, TD_level, TD_NEW, TD_OLD, args";
+
+ /*
+ * The code generated for this trigger is:
proname(internal_args)
+ * source
+ */
+ int length =
+ strlen(proname) + strlen(source) + strlen(internal_args) + 4;
+
+ /*
+ * Allocate a context that will hold all the Postgres data for
the
+ * procedure.
+ */
+ proc_cxt = AllocSetContextCreate(TopMemoryContext,
+
"PL/Sample function", ALLOCSET_SMALL_SIZES);
+
+ trigger_code = (char *) palloc0(length * sizeof(char));
+ trigger_code[0] = '\0';
+ strcpy(trigger_code, proname);
+ strcat(trigger_code, "(");
+ strcat(trigger_code, internal_args);
+ strcat(trigger_code, ") ");
+ strcat(trigger_code, source);
+
+ /*
+ * Compile trigger code here, or lookup cache of compiled code
if
+ * necessary.
+ */
+
+ old_cxt = MemoryContextSwitchTo(proc_cxt);
+
+ MemoryContextSwitchTo(old_cxt);
+ }
+ PG_CATCH();
+ {
+ PG_RE_THROW();
+ }
+ PG_END_TRY();
+
+ pfree(source);
+
+ ReleaseSysCache(pl_tuple);
+
+ PG_TRY();
+ {
+ int i;
+
+ ereport(NOTICE,
+ (errmsg("trigger name: %s",
trigdata->tg_trigger->tgname)));
+ string = SPI_getrelname(trigdata->tg_relation);
+ ereport(NOTICE, (errmsg("trigger relation: %s", string)));
+ pfree(string);
+
+ string = SPI_getnspname(trigdata->tg_relation);
+ ereport(NOTICE, (errmsg("trigger relation schema: %s",
string)));
+ pfree(string);
+
+ /* Example handling of different trigger aspects. */
+
+ if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
+ {
+ ereport(NOTICE, (errmsg("triggered by INSERT")));
+ rettup = trigdata->tg_trigtuple;
+ }
+ else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
+ {
+ ereport(NOTICE, (errmsg("triggered by DELETE")));
+ rettup = trigdata->tg_trigtuple;
+ }
+ else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
+ {
+ ereport(NOTICE, (errmsg("triggered by UPDATE")));
+ rettup = trigdata->tg_trigtuple;
+ }
+ else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
+ {
+ ereport(NOTICE, (errmsg("triggered by TRUNCATE")));
+ rettup = trigdata->tg_trigtuple;
+ }
+ else
+ elog(ERROR, "unrecognized event: %u",
trigdata->tg_event);
+
+ if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
+ ereport(NOTICE, (errmsg("triggered BEFORE")));
+ else if (TRIGGER_FIRED_AFTER(trigdata->tg_event))
+ ereport(NOTICE, (errmsg("triggered AFTER")));
+ else if (TRIGGER_FIRED_INSTEAD(trigdata->tg_event))
+ ereport(NOTICE, (errmsg("triggered INSTEAD OF")));
+ else
+ elog(ERROR, "unrecognized when: %u",
trigdata->tg_event);
+
+ if (TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
+ ereport(NOTICE, (errmsg("triggered per row")));
+ else if (TRIGGER_FIRED_FOR_STATEMENT(trigdata->tg_event))
+ ereport(NOTICE, (errmsg("triggered per statement")));
+ else
+ elog(ERROR, "unrecognized level: %u",
trigdata->tg_event);
+
+ /*
+ * Iterate through all of the trigger arguments, printing each
input
+ * value.
+ */
+ for (i = 0; i < trigdata->tg_trigger->tgnargs; i++)
+ ereport(NOTICE,
+ (errmsg("trigger arg[%i]: %s", i,
+
trigdata->tg_trigger->tgargs[i])));
+ }
+ PG_CATCH();
+ {
+ PG_RE_THROW();
+ }
+ PG_END_TRY();
+
+ if (SPI_finish() != SPI_OK_FINISH)
+ elog(ERROR, "SPI_finish() failed");
+
+ return rettup;
+}
diff --git a/src/test/modules/plsample/sql/plsample.sql
b/src/test/modules/plsample/sql/plsample.sql
index bf0fddac7f..ac06e99643 100644
--- a/src/test/modules/plsample/sql/plsample.sql
+++ b/src/test/modules/plsample/sql/plsample.sql
@@ -13,3 +13,31 @@ AS $$
Example of source with void result.
$$ LANGUAGE plsample;
SELECT plsample_result_void('{foo, bar, hoge}');
+
+CREATE FUNCTION my_trigger_func() RETURNS trigger AS $$
+if TD_event == "INSERT"
+ return TD_NEW
+elseif TD_event == "UPDATE"
+ return TD_NEW
+else
+ return "OK"
+end
+$$ language plsample;
+
+CREATE TABLE my_table (num integer, description text);
+CREATE TRIGGER my_trigger_func BEFORE INSERT OR UPDATE ON my_table
+ FOR EACH ROW EXECUTE FUNCTION my_trigger_func();
+CREATE TRIGGER my_trigger_func2 AFTER INSERT OR UPDATE ON my_table
+ FOR EACH ROW EXECUTE FUNCTION my_trigger_func(8);
+
+INSERT INTO my_table (num, description)
+VALUES (1, 'first');
+
+UPDATE my_table
+SET description = 'first, modified once'
+WHERE num = 1;
+
+DROP TRIGGER my_trigger_func ON my_table;
+DROP TRIGGER my_trigger_func2 ON my_table;
+DROP FUNCTION my_trigger_func;
+
