open-dsi
/
postgres
mirror of https://github.com/postgres/postgres
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Speed up plpgsql trigger startup by introducing "promises".

Browse Source 
Over the years we've accreted quite a few special variables that are
predefined in plpgsql trigger functions.  The cost of initializing these
variables to their defined values turns out to be a significant part of
the runtime of simple triggers; but, undoubtedly, most real-world triggers
never examine the values of most of these variables.

To improve matters, invent the notion of a variable that has a "promise"
attached to it, specifying which of the predetermined values should be
assigned to the variable if anything ever reads it.  This eliminates all
the unneeded startup overhead, in return for a small penalty on accesses
to these variables.

Tom Lane, reviewed by Pavel Stehule

Discussion: https://postgr.es/m/11986.1514407114@sss.pgh.pa.us
pull/31/merge
Tom Lane 8 years ago
parent 40301c1c8b
commit fd333bc763
5 changed files with 306 additions and 142 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 50
      src/pl/plpgsql/src/pl_comp.c
  2. 334
      src/pl/plpgsql/src/pl_exec.c
  3. 5
      src/pl/plpgsql/src/pl_funcs.c
  4. 3
      src/pl/plpgsql/src/pl_gram.y
  5. 56
      src/pl/plpgsql/src/plpgsql.h

50
src/pl/plpgsql/src/pl_comp.c
Unescape View File

@ -607,7 +607,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_name_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_NAME;
/* Add the variable tg_when */
var = plpgsql_build_variable("tg_when", 0,
@ -615,7 +617,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_when_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_WHEN;
/* Add the variable tg_level */
var = plpgsql_build_variable("tg_level", 0,
@ -623,7 +627,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_level_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_LEVEL;
/* Add the variable tg_op */
var = plpgsql_build_variable("tg_op", 0,
@ -631,7 +637,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_op_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_OP;
/* Add the variable tg_relid */
var = plpgsql_build_variable("tg_relid", 0,
@ -639,7 +647,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_relid_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_RELID;
/* Add the variable tg_relname */
var = plpgsql_build_variable("tg_relname", 0,
@ -647,7 +657,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_relname_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_TABLE_NAME;
/* tg_table_name is now preferred to tg_relname */
var = plpgsql_build_variable("tg_table_name", 0,
@ -655,7 +667,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_table_name_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_TABLE_NAME;
/* add the variable tg_table_schema */
var = plpgsql_build_variable("tg_table_schema", 0,
@ -663,7 +677,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_table_schema_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_TABLE_SCHEMA;
/* Add the variable tg_nargs */
var = plpgsql_build_variable("tg_nargs", 0,
@ -671,7 +687,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
InvalidOid),
true);
function->tg_nargs_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_NARGS;
/* Add the variable tg_argv */
var = plpgsql_build_variable("tg_argv", 0,
@ -679,7 +697,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_argv_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_ARGV;
break;
@ -701,7 +721,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_event_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_EVENT;
/* Add the variable tg_tag */
var = plpgsql_build_variable("tg_tag", 0,
@ -709,7 +731,9 @@ do_compile(FunctionCallInfo fcinfo,
-1,
function->fn_input_collation),
true);
function->tg_tag_varno = var->dno;
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
var->dtype = PLPGSQL_DTYPE_PROMISE;
((PLpgSQL_var *) var)->promise = PLPGSQL_PROMISE_TG_TAG;
break;
@ -1878,6 +1902,7 @@ build_row_from_vars(PLpgSQL_variable **vars, int numvars)
switch (var->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
typoid = ((PLpgSQL_var *) var)->datatype->typoid;
typmod = ((PLpgSQL_var *) var)->datatype->atttypmod;
typcoll = ((PLpgSQL_var *) var)->datatype->collation;
@ -2196,6 +2221,7 @@ plpgsql_finish_datums(PLpgSQL_function *function)
switch (function->datums[i]->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
copiable_size += MAXALIGN(sizeof(PLpgSQL_var));
break;
case PLPGSQL_DTYPE_REC:

334
src/pl/plpgsql/src/pl_exec.c
Unescape View File

@ -237,6 +237,8 @@ static void coerce_function_result_tuple(PLpgSQL_execstate *estate,
static void plpgsql_exec_error_callback(void *arg);
static void copy_plpgsql_datums(PLpgSQL_execstate *estate,
PLpgSQL_function *func);
static void plpgsql_fulfill_promise(PLpgSQL_execstate *estate,
PLpgSQL_var *var);
static MemoryContext get_stmt_mcontext(PLpgSQL_execstate *estate);
static void push_stmt_mcontext(PLpgSQL_execstate *estate);
static void pop_stmt_mcontext(PLpgSQL_execstate *estate);
@ -547,6 +549,7 @@ plpgsql_exec_function(PLpgSQL_function *func, FunctionCallInfo fcinfo,
break;
default:
/* Anything else should not be an argument variable */
elog(ERROR, "unrecognized dtype: %d", func->datums[i]->dtype);
}
}
@ -834,10 +837,8 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
{
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
int i;
int rc;
TupleDesc tupdesc;
PLpgSQL_var *var;
PLpgSQL_rec *rec_new,
*rec_old;
HeapTuple rettup;
@ -846,6 +847,7 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
* Setup the execution state
*/
plpgsql_estate_setup(&estate, func, NULL, NULL);
estate.trigdata = trigdata;
/*
* Setup error traceback support for ereport()
@ -906,106 +908,6 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
rc = SPI_register_trigger_data(trigdata);
Assert(rc >= 0);
/*
* Assign the special tg_ variables
*/
var = (PLpgSQL_var *) (estate.datums[func->tg_op_varno]);
if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
assign_text_var(&estate, var, "INSERT");
else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
assign_text_var(&estate, var, "UPDATE");
else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
assign_text_var(&estate, var, "DELETE");
else if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
assign_text_var(&estate, var, "TRUNCATE");
else
elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, UPDATE, or TRUNCATE");
var = (PLpgSQL_var *) (estate.datums[func->tg_name_varno]);
assign_simple_var(&estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(trigdata->tg_trigger->tgname)),
false, true);
var = (PLpgSQL_var *) (estate.datums[func->tg_when_varno]);
if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
assign_text_var(&estate, var, "BEFORE");
else if (TRIGGER_FIRED_AFTER(trigdata->tg_event))
assign_text_var(&estate, var, "AFTER");
else if (TRIGGER_FIRED_INSTEAD(trigdata->tg_event))
assign_text_var(&estate, var, "INSTEAD OF");
else
elog(ERROR, "unrecognized trigger execution time: not BEFORE, AFTER, or INSTEAD OF");
var = (PLpgSQL_var *) (estate.datums[func->tg_level_varno]);
if (TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
assign_text_var(&estate, var, "ROW");
else if (TRIGGER_FIRED_FOR_STATEMENT(trigdata->tg_event))
assign_text_var(&estate, var, "STATEMENT");
else
elog(ERROR, "unrecognized trigger event type: not ROW or STATEMENT");
var = (PLpgSQL_var *) (estate.datums[func->tg_relid_varno]);
assign_simple_var(&estate, var,
ObjectIdGetDatum(trigdata->tg_relation->rd_id),
false, false);
var = (PLpgSQL_var *) (estate.datums[func->tg_relname_varno]);
assign_simple_var(&estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(RelationGetRelationName(trigdata->tg_relation))),
false, true);
var = (PLpgSQL_var *) (estate.datums[func->tg_table_name_varno]);
assign_simple_var(&estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(RelationGetRelationName(trigdata->tg_relation))),
false, true);
var = (PLpgSQL_var *) (estate.datums[func->tg_table_schema_varno]);
assign_simple_var(&estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(get_namespace_name(
RelationGetNamespace(
trigdata->tg_relation)))),
false, true);
var = (PLpgSQL_var *) (estate.datums[func->tg_nargs_varno]);
assign_simple_var(&estate, var,
Int16GetDatum(trigdata->tg_trigger->tgnargs),
false, false);
var = (PLpgSQL_var *) (estate.datums[func->tg_argv_varno]);
if (trigdata->tg_trigger->tgnargs > 0)
{
/*
* For historical reasons, tg_argv[] subscripts start at zero not one.
* So we can't use construct_array().
*/
int nelems = trigdata->tg_trigger->tgnargs;
Datum *elems;
int dims[1];
int lbs[1];
elems = palloc(sizeof(Datum) * nelems);
for (i = 0; i < nelems; i++)
elems[i] = CStringGetTextDatum(trigdata->tg_trigger->tgargs[i]);
dims[0] = nelems;
lbs[0] = 0;
assign_simple_var(&estate, var,
PointerGetDatum(construct_md_array(elems, NULL,
1, dims, lbs,
TEXTOID,
-1, false, 'i')),
false, true);
}
else
{
assign_simple_var(&estate, var, (Datum) 0, true, false);
}
estate.err_text = gettext_noop("during function entry");
/*
@ -1153,12 +1055,12 @@ plpgsql_exec_event_trigger(PLpgSQL_function *func, EventTriggerData *trigdata)
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
int rc;
PLpgSQL_var *var;
/*
* Setup the execution state
*/
plpgsql_estate_setup(&estate, func, NULL, NULL);
estate.evtrigdata = trigdata;
/*
* Setup error traceback support for ereport()
@ -1174,15 +1076,6 @@ plpgsql_exec_event_trigger(PLpgSQL_function *func, EventTriggerData *trigdata)
estate.err_text = gettext_noop("during initialization of execution state");
copy_plpgsql_datums(&estate, func);
/*
* Assign the special tg_ variables
*/
var = (PLpgSQL_var *) (estate.datums[func->tg_event_varno]);
assign_text_var(&estate, var, trigdata->event);
var = (PLpgSQL_var *) (estate.datums[func->tg_tag_varno]);
assign_text_var(&estate, var, trigdata->tag);
/*
* Let the instrumentation plugin peek at this function
*/
@ -1321,6 +1214,7 @@ copy_plpgsql_datums(PLpgSQL_execstate *estate,
switch (indatum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
outdatum = (PLpgSQL_datum *) ws_next;
memcpy(outdatum, indatum, sizeof(PLpgSQL_var));
ws_next += MAXALIGN(sizeof(PLpgSQL_var));
@ -1356,6 +1250,166 @@ copy_plpgsql_datums(PLpgSQL_execstate *estate,
Assert(ws_next == workspace + func->copiable_size);
}
/*
* If the variable has an armed "promise", compute the promised value
* and assign it to the variable.
* The assignment automatically disarms the promise.
*/
static void
plpgsql_fulfill_promise(PLpgSQL_execstate *estate,
PLpgSQL_var *var)
{
MemoryContext oldcontext;
if (var->promise == PLPGSQL_PROMISE_NONE)
return; /* nothing to do */
/*
* This will typically be invoked in a short-lived context such as the
* mcontext. We must create variable values in the estate's datum
* context. This quick-and-dirty solution risks leaking some additional
* cruft there, but since any one promise is honored at most once per
* function call, it's probably not worth being more careful.
*/
oldcontext = MemoryContextSwitchTo(estate->datum_context);
switch (var->promise)
{
case PLPGSQL_PROMISE_TG_NAME:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(estate->trigdata->tg_trigger->tgname)),
false, true);
break;
case PLPGSQL_PROMISE_TG_WHEN:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_BEFORE(estate->trigdata->tg_event))
assign_text_var(estate, var, "BEFORE");
else if (TRIGGER_FIRED_AFTER(estate->trigdata->tg_event))
assign_text_var(estate, var, "AFTER");
else if (TRIGGER_FIRED_INSTEAD(estate->trigdata->tg_event))
assign_text_var(estate, var, "INSTEAD OF");
else
elog(ERROR, "unrecognized trigger execution time: not BEFORE, AFTER, or INSTEAD OF");
break;
case PLPGSQL_PROMISE_TG_LEVEL:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_FOR_ROW(estate->trigdata->tg_event))
assign_text_var(estate, var, "ROW");
else if (TRIGGER_FIRED_FOR_STATEMENT(estate->trigdata->tg_event))
assign_text_var(estate, var, "STATEMENT");
else
elog(ERROR, "unrecognized trigger event type: not ROW or STATEMENT");
break;
case PLPGSQL_PROMISE_TG_OP:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_BY_INSERT(estate->trigdata->tg_event))
assign_text_var(estate, var, "INSERT");
else if (TRIGGER_FIRED_BY_UPDATE(estate->trigdata->tg_event))
assign_text_var(estate, var, "UPDATE");
else if (TRIGGER_FIRED_BY_DELETE(estate->trigdata->tg_event))
assign_text_var(estate, var, "DELETE");
else if (TRIGGER_FIRED_BY_TRUNCATE(estate->trigdata->tg_event))
assign_text_var(estate, var, "TRUNCATE");
else
elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, UPDATE, or TRUNCATE");
break;
case PLPGSQL_PROMISE_TG_RELID:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
ObjectIdGetDatum(estate->trigdata->tg_relation->rd_id),
false, false);
break;
case PLPGSQL_PROMISE_TG_TABLE_NAME:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(RelationGetRelationName(estate->trigdata->tg_relation))),
false, true);
break;
case PLPGSQL_PROMISE_TG_TABLE_SCHEMA:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(get_namespace_name(RelationGetNamespace(estate->trigdata->tg_relation)))),
false, true);
break;
case PLPGSQL_PROMISE_TG_NARGS:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
Int16GetDatum(estate->trigdata->tg_trigger->tgnargs),
false, false);
break;
case PLPGSQL_PROMISE_TG_ARGV:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (estate->trigdata->tg_trigger->tgnargs > 0)
{
/*
* For historical reasons, tg_argv[] subscripts start at zero
* not one. So we can't use construct_array().
*/
int nelems = estate->trigdata->tg_trigger->tgnargs;
Datum *elems;
int dims[1];
int lbs[1];
int i;
elems = palloc(sizeof(Datum) * nelems);
for (i = 0; i < nelems; i++)
elems[i] = CStringGetTextDatum(estate->trigdata->tg_trigger->tgargs[i]);
dims[0] = nelems;
lbs[0] = 0;
assign_simple_var(estate, var,
PointerGetDatum(construct_md_array(elems, NULL,
1, dims, lbs,
TEXTOID,
-1, false, 'i')),
false, true);
}
else
{
assign_simple_var(estate, var, (Datum) 0, true, false);
}
break;
case PLPGSQL_PROMISE_TG_EVENT:
if (estate->evtrigdata == NULL)
elog(ERROR, "event trigger promise is not in an event trigger function");
assign_text_var(estate, var, estate->evtrigdata->event);
break;
case PLPGSQL_PROMISE_TG_TAG:
if (estate->evtrigdata == NULL)
elog(ERROR, "event trigger promise is not in an event trigger function");
assign_text_var(estate, var, estate->evtrigdata->tag);
break;
default:
elog(ERROR, "unrecognized promise type: %d", var->promise);
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Create a memory context for statement-lifespan variables, if we don't
* have one already. It will be a child of stmt_mcontext_parent, which is
@ -1464,6 +1518,10 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
/*
* The set of dtypes handled here must match plpgsql_add_initdatums().
*
* Note that we currently don't support promise datums within blocks,
* only at a function's outermost scope, so we needn't handle those
* here.
*/
switch (datum->dtype)
{
@ -2778,6 +2836,12 @@ exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
switch (retvar->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) retvar);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) retvar;
@ -2917,6 +2981,12 @@ exec_stmt_return_next(PLpgSQL_execstate *estate,
switch (retvar->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) retvar);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) retvar;
@ -3487,6 +3557,8 @@ plpgsql_estate_setup(PLpgSQL_execstate *estate,
func->cur_estate = estate;
estate->func = func;
estate->trigdata = NULL;
estate->evtrigdata = NULL;
estate->retval = (Datum) 0;
estate->retisnull = true;
@ -4542,6 +4614,7 @@ exec_assign_value(PLpgSQL_execstate *estate,
switch (target->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
/*
* Target is a variable
@ -4604,10 +4677,16 @@ exec_assign_value(PLpgSQL_execstate *estate,
* cannot reliably be made any earlier; we have to be looking
* at the object's standard R/W pointer to be sure pointer
* equality is meaningful.
*
* Also, if it's a promise variable, we should disarm the
* promise in any case --- otherwise, assigning null to an
* armed promise variable would fail to disarm the promise.
*/
if (var->value != newvalue || var->isnull || isNull)
assign_simple_var(estate, var, newvalue, isNull,
(!var->datatype->typbyval && !isNull));
else
var->promise = PLPGSQL_PROMISE_NONE;
break;
}
@ -4951,6 +5030,12 @@ exec_eval_datum(PLpgSQL_execstate *estate,
switch (datum->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) datum);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
@ -5093,6 +5178,7 @@ plpgsql_exec_get_datum_type(PLpgSQL_execstate *estate,
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
@ -5176,6 +5262,7 @@ plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
@ -5874,6 +5961,7 @@ plpgsql_param_fetch(ParamListInfo params,
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
/* always safe */
break;
@ -5989,8 +6077,8 @@ plpgsql_param_compile(ParamListInfo params, Param *param,
* Select appropriate eval function. It seems worth special-casing
* DTYPE_VAR and DTYPE_RECFIELD for performance. Also, we can determine
* in advance whether MakeExpandedObjectReadOnly() will be required.
* Currently, only VAR and REC datums could contain read/write expanded
* objects.
* Currently, only VAR/PROMISE and REC datums could contain read/write
* expanded objects.
*/
if (datum->dtype == PLPGSQL_DTYPE_VAR)
{
@ -6002,6 +6090,14 @@ plpgsql_param_compile(ParamListInfo params, Param *param,
}
else if (datum->dtype == PLPGSQL_DTYPE_RECFIELD)
scratch.d.cparam.paramfunc = plpgsql_param_eval_recfield;
else if (datum->dtype == PLPGSQL_DTYPE_PROMISE)
{
if (dno != expr->rwparam &&
((PLpgSQL_var *) datum)->datatype->typlen == -1)
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic_ro;
else
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic;
}
else if (datum->dtype == PLPGSQL_DTYPE_REC &&
dno != expr->rwparam)
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic_ro;
@ -7680,7 +7776,8 @@ static void
assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
Datum newvalue, bool isnull, bool freeable)
{
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
Assert(var->dtype == PLPGSQL_DTYPE_VAR ||
var->dtype == PLPGSQL_DTYPE_PROMISE);
/* Free the old value if needed */
if (var->freeval)
{
@ -7695,6 +7792,13 @@ assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
var->value = newvalue;
var->isnull = isnull;
var->freeval = freeable;
/*
* If it's a promise variable, then either we just assigned the promised
* value, or the user explicitly assigned an overriding value. Either
* way, cancel the promise.
*/
var->promise = PLPGSQL_PROMISE_NONE;
}
/*

5
src/pl/plpgsql/src/pl_funcs.c
Unescape View File

@ -729,6 +729,7 @@ plpgsql_free_function_memory(PLpgSQL_function *func)
switch (d->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) d;
@ -1582,6 +1583,7 @@ plpgsql_dumptree(PLpgSQL_function *func)
switch (d->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) d;
@ -1608,6 +1610,9 @@ plpgsql_dumptree(PLpgSQL_function *func)
dump_expr(var->cursor_explicit_expr);
printf("\n");
}
if (var->promise != PLPGSQL_PROMISE_NONE)
printf(" PROMISE %d\n",
(int) var->promise);
}
break;
case PLPGSQL_DTYPE_ROW:

3
src/pl/plpgsql/src/pl_gram.y
Unescape View File

@ -3170,6 +3170,7 @@ make_return_stmt(int location)
if (tok == T_DATUM && plpgsql_peek() == ';' &&
(yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_VAR ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_PROMISE ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_ROW ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_REC))
{
@ -3231,6 +3232,7 @@ make_return_next_stmt(int location)
if (tok == T_DATUM && plpgsql_peek() == ';' &&
(yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_VAR ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_PROMISE ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_ROW ||
yylval.wdatum.datum->dtype == PLPGSQL_DTYPE_REC))
{
@ -3318,6 +3320,7 @@ check_assignable(PLpgSQL_datum *datum, int location)
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
if (((PLpgSQL_var *) datum)->isconst)
ereport(ERROR,
(errcode(ERRCODE_ERROR_IN_ASSIGNMENT),

56
src/pl/plpgsql/src/plpgsql.h
Unescape View File

@ -63,9 +63,29 @@ typedef enum PLpgSQL_datum_type
PLPGSQL_DTYPE_ROW,
PLPGSQL_DTYPE_REC,
PLPGSQL_DTYPE_RECFIELD,
PLPGSQL_DTYPE_ARRAYELEM
PLPGSQL_DTYPE_ARRAYELEM,
PLPGSQL_DTYPE_PROMISE
} PLpgSQL_datum_type;
/*
* DTYPE_PROMISE datums have these possible ways of computing the promise
*/
typedef enum PLpgSQL_promise_type
{
PLPGSQL_PROMISE_NONE = 0, /* not a promise, or promise satisfied */
PLPGSQL_PROMISE_TG_NAME,
PLPGSQL_PROMISE_TG_WHEN,
PLPGSQL_PROMISE_TG_LEVEL,
PLPGSQL_PROMISE_TG_OP,
PLPGSQL_PROMISE_TG_RELID,
PLPGSQL_PROMISE_TG_TABLE_NAME,
PLPGSQL_PROMISE_TG_TABLE_SCHEMA,
PLPGSQL_PROMISE_TG_NARGS,
PLPGSQL_PROMISE_TG_ARGV,
PLPGSQL_PROMISE_TG_EVENT,
PLPGSQL_PROMISE_TG_TAG
} PLpgSQL_promise_type;
/*
* Variants distinguished in PLpgSQL_type structs
*/
@ -248,6 +268,14 @@ typedef struct PLpgSQL_variable
/*
* Scalar variable
*
* DTYPE_VAR and DTYPE_PROMISE datums both use this struct type.
* A PROMISE datum works exactly like a VAR datum for most purposes,
* but if it is read without having previously been assigned to, then
* a special "promised" value is computed and assigned to the datum
* before the read is performed. This technique avoids the overhead of
* computing the variable's value in cases where we expect that many
* functions will never read it.
*/
typedef struct PLpgSQL_var
{
@ -271,9 +299,18 @@ typedef struct PLpgSQL_var
int cursor_explicit_argrow;
int cursor_options;
/* Fields below here can change at runtime */
Datum value;
bool isnull;
bool freeval;
/*
* The promise field records which "promised" value to assign if the
* promise must be honored. If it's a normal variable, or the promise has
* been fulfilled, this is PLPGSQL_PROMISE_NONE.
*/
PLpgSQL_promise_type promise;
} PLpgSQL_var;
/*
@ -869,20 +906,6 @@ typedef struct PLpgSQL_function
int found_varno;
int new_varno;
int old_varno;
int tg_name_varno;
int tg_when_varno;
int tg_level_varno;
int tg_op_varno;
int tg_relid_varno;
int tg_relname_varno;
int tg_table_name_varno;
int tg_table_schema_varno;
int tg_nargs_varno;
int tg_argv_varno;
/* for event triggers */
int tg_event_varno;
int tg_tag_varno;
PLpgSQL_resolve_option resolve_option;
@ -912,6 +935,9 @@ typedef struct PLpgSQL_execstate
{
PLpgSQL_function *func; /* function being executed */
TriggerData *trigdata; /* if regular trigger, data about firing */
EventTriggerData *evtrigdata; /* if event trigger, data about firing */
Datum retval;
bool retisnull;
Oid rettype; /* type of current retval */

Write Preview
Loading…
Cancel
Save