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Support polymorphic functions in plpgsql. Along the way, replace 

linked-list search of function cache with hash-table lookup.
By Joe Conway.
This commit is contained in:
Tom Lane 2003-07-01 21:47:09 +00:00
parent cc3002313f
commit b837c99210
3 changed files with 314 additions and 132 deletions
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340
src/pl/plpgsql/src/pl_comp.c
View File

@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.58 2003/05/05 16:46:27 tgl Exp $
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.59 2003/07/01 21:47:09 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@ -79,10 +79,38 @@ int plpgsql_DumpExecTree = 0;
PLpgSQL_function *plpgsql_curr_compile;
/* ----------
* Hash table for compiled functions
* ----------
*/
static HTAB *plpgsql_HashTable = (HTAB *) NULL;
typedef struct plpgsql_hashent
{
PLpgSQL_func_hashkey key;
PLpgSQL_function *function;
} plpgsql_HashEnt;
#define FUNCS_PER_USER 128 /* initial table size */
/* ----------
* static prototypes
* ----------
*/
static PLpgSQL_function *do_compile(FunctionCallInfo fcinfo,
HeapTuple procTup,
PLpgSQL_func_hashkey *hashkey);
static void plpgsql_compile_error_callback(void *arg);
static PLpgSQL_type *build_datatype(HeapTuple typeTup, int32 typmod);
static void compute_function_hashkey(FmgrInfo *flinfo,
Form_pg_proc procStruct,
PLpgSQL_func_hashkey *hashkey);
static void plpgsql_HashTableInit(void);
static PLpgSQL_function *plpgsql_HashTableLookup(PLpgSQL_func_hashkey *func_key);
static void plpgsql_HashTableInsert(PLpgSQL_function *function,
PLpgSQL_func_hashkey *func_key);
static void plpgsql_HashTableDelete(PLpgSQL_function *function);
/*
* This routine is a crock, and so is everyplace that calls it. The problem
@ -103,44 +131,129 @@ perm_fmgr_info(Oid functionId, FmgrInfo *finfo)
/* ----------
* plpgsql_compile Given a pg_proc's oid, make
* an execution tree for it.
* plpgsql_compile Make an execution tree for a PL/pgSQL function.
*
* Note: it's important for this to fall through quickly if the function
* has already been compiled.
* ----------
*/
PLpgSQL_function *
plpgsql_compile(Oid fn_oid, int functype)
plpgsql_compile(FunctionCallInfo fcinfo)
{
int parse_rc;
Oid funcOid = fcinfo->flinfo->fn_oid;
HeapTuple procTup;
Form_pg_proc procStruct;
PLpgSQL_function *function;
PLpgSQL_func_hashkey hashkey;
bool hashkey_valid = false;
/*
* Lookup the pg_proc tuple by Oid; we'll need it in any case
*/
procTup = SearchSysCache(PROCOID,
ObjectIdGetDatum(funcOid),
0, 0, 0);
if (!HeapTupleIsValid(procTup))
elog(ERROR, "plpgsql: cache lookup for proc %u failed", funcOid);
procStruct = (Form_pg_proc) GETSTRUCT(procTup);
/*
* See if there's already a cache entry for the current FmgrInfo.
* If not, try to find one in the hash table.
*/
function = (PLpgSQL_function *) fcinfo->flinfo->fn_extra;
if (!function)
{
/* First time through in this backend? If so, init hashtable */
if (!plpgsql_HashTable)
plpgsql_HashTableInit();
/* Compute hashkey using function signature and actual arg types */
compute_function_hashkey(fcinfo->flinfo, procStruct, &hashkey);
hashkey_valid = true;
/* And do the lookup */
function = plpgsql_HashTableLookup(&hashkey);
}
if (function)
{
/* We have a compiled function, but is it still valid? */
if (!(function->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
function->fn_cmin == HeapTupleHeaderGetCmin(procTup->t_data)))
{
/*
* Nope, drop the hashtable entry. XXX someday, free all the
* subsidiary storage as well.
*/
plpgsql_HashTableDelete(function);
function = NULL;
}
}
/*
* If the function wasn't found or was out-of-date, we have to compile it
*/
if (!function)
{
/*
* Calculate hashkey if we didn't already; we'll need it to store
* the completed function.
*/
if (!hashkey_valid)
compute_function_hashkey(fcinfo->flinfo, procStruct, &hashkey);
/*
* Do the hard part.
*/
function = do_compile(fcinfo, procTup, &hashkey);
}
ReleaseSysCache(procTup);
/*
* Save pointer in FmgrInfo to avoid search on subsequent calls
*/
fcinfo->flinfo->fn_extra = (void *) function;
/*
* Finally return the compiled function
*/
return function;
}
/*
* This is the slow part of plpgsql_compile().
*/
static PLpgSQL_function *
do_compile(FunctionCallInfo fcinfo,
HeapTuple procTup,
PLpgSQL_func_hashkey *hashkey)
{
Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
int functype = CALLED_AS_TRIGGER(fcinfo) ? T_TRIGGER : T_FUNCTION;
PLpgSQL_function *function;
char *proc_source;
HeapTuple typeTup;
Form_pg_type typeStruct;
char *proc_source;
PLpgSQL_function *function;
PLpgSQL_var *var;
PLpgSQL_row *row;
PLpgSQL_rec *rec;
int i;
int arg_varnos[FUNC_MAX_ARGS];
ErrorContextCallback plerrcontext;
int parse_rc;
Oid rettypeid;
/*
* Lookup the pg_proc tuple by Oid
* Setup the scanner input and error info. We assume that this
* function cannot be invoked recursively, so there's no need to save
* and restore the static variables used here.
*/
procTup = SearchSysCache(PROCOID,
ObjectIdGetDatum(fn_oid),
0, 0, 0);
if (!HeapTupleIsValid(procTup))
elog(ERROR, "plpgsql: cache lookup for proc %u failed", fn_oid);
/*
* Setup the scanner input and error info. We assume that this function
* cannot be invoked recursively, so there's no need to save and restore
* the static variables used here.
*/
procStruct = (Form_pg_proc) GETSTRUCT(procTup);
proc_source = DatumGetCString(DirectFunctionCall1(textout,
PointerGetDatum(&procStruct->prosrc)));
PointerGetDatum(&procStruct->prosrc)));
plpgsql_scanner_init(proc_source, functype);
pfree(proc_source);
@ -171,11 +284,11 @@ plpgsql_compile(Oid fn_oid, int functype)
* Create the new function node
*/
function = malloc(sizeof(PLpgSQL_function));
memset(function, 0, sizeof(PLpgSQL_function));
MemSet(function, 0, sizeof(PLpgSQL_function));
plpgsql_curr_compile = function;
function->fn_name = strdup(NameStr(procStruct->proname));
function->fn_oid = fn_oid;
function->fn_oid = fcinfo->flinfo->fn_oid;
function->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
function->fn_cmin = HeapTupleHeaderGetCmin(procTup->t_data);
function->fn_functype = functype;
@ -184,40 +297,56 @@ plpgsql_compile(Oid fn_oid, int functype)
{
case T_FUNCTION:
/*
* Check for a polymorphic returntype. If found, use the actual
* returntype type from the caller's FuncExpr node, if we
* have one.
*/
rettypeid = procStruct->prorettype;
if (rettypeid == ANYARRAYOID || rettypeid == ANYELEMENTOID)
{
rettypeid = get_fn_expr_rettype(fcinfo->flinfo);
if (!OidIsValid(rettypeid))
elog(ERROR, "could not determine actual return type "
"for polymorphic function %s",
plpgsql_error_funcname);
}
/*
* Normal function has a defined returntype
*/
function->fn_rettype = procStruct->prorettype;
function->fn_rettype = rettypeid;
function->fn_retset = procStruct->proretset;
/*
* Lookup the functions return type
*/
typeTup = SearchSysCache(TYPEOID,
ObjectIdGetDatum(procStruct->prorettype),
ObjectIdGetDatum(rettypeid),
0, 0, 0);
if (!HeapTupleIsValid(typeTup))
elog(ERROR, "cache lookup for return type %u failed",
procStruct->prorettype);
rettypeid);
typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
/* Disallow pseudotype result, except VOID or RECORD */
/* (note we already replaced ANYARRAY/ANYELEMENT) */
if (typeStruct->typtype == 'p')
{
if (procStruct->prorettype == VOIDOID ||
procStruct->prorettype == RECORDOID)
/* okay */ ;
else if (procStruct->prorettype == TRIGGEROID)
if (rettypeid == VOIDOID ||
rettypeid == RECORDOID)
/* okay */ ;
else if (rettypeid == TRIGGEROID)
elog(ERROR, "plpgsql functions cannot return type %s"
"\n\texcept when used as triggers",
format_type_be(procStruct->prorettype));
format_type_be(rettypeid));
else
elog(ERROR, "plpgsql functions cannot return type %s",
format_type_be(procStruct->prorettype));
format_type_be(rettypeid));
}
if (typeStruct->typrelid != InvalidOid ||
procStruct->prorettype == RECORDOID)
rettypeid == RECORDOID)
function->fn_retistuple = true;
else
{
@ -229,29 +358,39 @@ plpgsql_compile(Oid fn_oid, int functype)
ReleaseSysCache(typeTup);
/*
* Create the variables for the procedures parameters
* Create the variables for the procedure's parameters
*/
for (i = 0; i < procStruct->pronargs; i++)
{
char buf[32];
Oid argtypeid;
snprintf(buf, sizeof(buf), "$%d", i + 1); /* name for variable */
/* name for variable */
snprintf(buf, sizeof(buf), "$%d", i + 1);
/*
* Since we already did the replacement of polymorphic
* argument types by actual argument types while computing
* the hashkey, we can just use those results.
*/
argtypeid = hashkey->argtypes[i];
/*
* Get the parameters type
*/
typeTup = SearchSysCache(TYPEOID,
ObjectIdGetDatum(procStruct->proargtypes[i]),
ObjectIdGetDatum(argtypeid),
0, 0, 0);
if (!HeapTupleIsValid(typeTup))
elog(ERROR, "cache lookup for argument type %u failed",
procStruct->proargtypes[i]);
argtypeid);
typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
/* Disallow pseudotype argument */
/* (note we already replaced ANYARRAY/ANYELEMENT) */
if (typeStruct->typtype == 'p')
elog(ERROR, "plpgsql functions cannot take type %s",
format_type_be(procStruct->proargtypes[i]));
format_type_be(argtypeid));
if (typeStruct->typrelid != InvalidOid)
{
@ -511,7 +650,14 @@ plpgsql_compile(Oid fn_oid, int functype)
function->datums[i] = plpgsql_Datums[i];
function->action = plpgsql_yylval.program;
ReleaseSysCache(procTup);
/* Debug dump for completed functions */
if (plpgsql_DumpExecTree)
plpgsql_dumptree(function);
/*
* add it to the hash table
*/
plpgsql_HashTableInsert(function, hashkey);
/*
* Pop the error context stack
@ -520,11 +666,6 @@ plpgsql_compile(Oid fn_oid, int functype)
plpgsql_error_funcname = NULL;
plpgsql_error_lineno = 0;
/*
* Finally return the compiled function
*/
if (plpgsql_DumpExecTree)
plpgsql_dumptree(function);
return function;
}
@ -1500,3 +1641,112 @@ plpgsql_yyerror(const char *s)
plpgsql_error_lineno = plpgsql_scanner_lineno();
elog(ERROR, "%s at or near \"%s\"", s, plpgsql_yytext);
}
/*
* Compute the hashkey for a given function invocation
*
* The hashkey is returned into the caller-provided storage at *hashkey.
*/
static void
compute_function_hashkey(FmgrInfo *flinfo,
Form_pg_proc procStruct,
PLpgSQL_func_hashkey *hashkey)
{
int i;
/* Make sure any unused bytes of the struct are zero */
MemSet(hashkey, 0, sizeof(PLpgSQL_func_hashkey));
hashkey->funcOid = flinfo->fn_oid;
/* get the argument types */
for (i = 0; i < procStruct->pronargs; i++)
{
Oid argtypeid = procStruct->proargtypes[i];
/*
* Check for polymorphic arguments. If found, use the actual
* parameter type from the caller's FuncExpr node, if we
* have one.
*
* We can support arguments of type ANY the same way as normal
* polymorphic arguments.
*/
if (argtypeid == ANYARRAYOID || argtypeid == ANYELEMENTOID ||
argtypeid == ANYOID)
{
argtypeid = get_fn_expr_argtype(flinfo, i);
if (!OidIsValid(argtypeid))
elog(ERROR, "could not determine actual argument "
"type for polymorphic function %s",
NameStr(procStruct->proname));
}
hashkey->argtypes[i] = argtypeid;
}
}
static void
plpgsql_HashTableInit(void)
{
HASHCTL ctl;
memset(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(PLpgSQL_func_hashkey);
ctl.entrysize = sizeof(plpgsql_HashEnt);
ctl.hash = tag_hash;
plpgsql_HashTable = hash_create("PLpgSQL function cache",
FUNCS_PER_USER,
&ctl,
HASH_ELEM | HASH_FUNCTION);
}
static PLpgSQL_function *
plpgsql_HashTableLookup(PLpgSQL_func_hashkey *func_key)
{
plpgsql_HashEnt *hentry;
hentry = (plpgsql_HashEnt*) hash_search(plpgsql_HashTable,
(void *) func_key,
HASH_FIND,
NULL);
if (hentry)
return hentry->function;
else
return (PLpgSQL_function *) NULL;
}
static void
plpgsql_HashTableInsert(PLpgSQL_function *function,
PLpgSQL_func_hashkey *func_key)
{
plpgsql_HashEnt *hentry;
bool found;
hentry = (plpgsql_HashEnt*) hash_search(plpgsql_HashTable,
(void *) func_key,
HASH_ENTER,
&found);
if (hentry == NULL)
elog(ERROR, "out of memory in plpgsql_HashTable");
if (found)
elog(WARNING, "trying to insert a function that exists");
hentry->function = function;
/* prepare back link from function to hashtable key */
function->fn_hashkey = &hentry->key;
}
static void
plpgsql_HashTableDelete(PLpgSQL_function *function)
{
plpgsql_HashEnt *hentry;
hentry = (plpgsql_HashEnt*) hash_search(plpgsql_HashTable,
(void *) function->fn_hashkey,
HASH_REMOVE,
NULL);
if (hentry == NULL)
elog(WARNING, "trying to delete function that does not exist");
}

87
src/pl/plpgsql/src/pl_handler.c
View File

@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_handler.c,v 1.12 2002/08/30 00:28:41 tgl Exp $
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_handler.c,v 1.13 2003/07/01 21:47:09 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@ -45,15 +45,6 @@
#include "utils/syscache.h"
/*
* Head of list of already-compiled functions
*/
static PLpgSQL_function *compiled_functions = NULL;
static bool func_up_to_date(PLpgSQL_function * func);
/* ----------
* plpgsql_call_handler
*
@ -67,8 +58,6 @@ PG_FUNCTION_INFO_V1(plpgsql_call_handler);
Datum
plpgsql_call_handler(PG_FUNCTION_ARGS)
{
bool isTrigger = CALLED_AS_TRIGGER(fcinfo);
Oid funcOid = fcinfo->flinfo->fn_oid;
PLpgSQL_function *func;
Datum retval;
@ -78,55 +67,14 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
if (SPI_connect() != SPI_OK_CONNECT)
elog(ERROR, "plpgsql: cannot connect to SPI manager");
/*
* Check if we already compiled this function and saved the pointer
* (ie, current FmgrInfo has been used before)
*/
func = (PLpgSQL_function *) fcinfo->flinfo->fn_extra;
if (func != NULL)
{
Assert(func->fn_oid == funcOid);
/*
* But is the function still up to date?
*/
if (!func_up_to_date(func))
func = NULL;
}
if (func == NULL)
{
/*
* Check if we already compiled this function for another caller
*/
for (func = compiled_functions; func != NULL; func = func->next)
{
if (funcOid == func->fn_oid && func_up_to_date(func))
break;
}
/*
* If not, do so and add it to the compiled ones
*/
if (func == NULL)
{
func = plpgsql_compile(funcOid,
isTrigger ? T_TRIGGER : T_FUNCTION);
func->next = compiled_functions;
compiled_functions = func;
}
/*
* Save pointer in FmgrInfo to avoid search on subsequent calls
*/
fcinfo->flinfo->fn_extra = (void *) func;
}
/* Find or compile the function */
func = plpgsql_compile(fcinfo);
/*
* Determine if called as function or trigger and call appropriate
* subhandler
*/
if (isTrigger)
if (CALLED_AS_TRIGGER(fcinfo))
retval = PointerGetDatum(plpgsql_exec_trigger(func,
(TriggerData *) fcinfo->context));
else
@ -140,30 +88,3 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
return retval;
}
/*
* Check to see if a compiled function is still up-to-date. This
* is needed because CREATE OR REPLACE FUNCTION can modify the
* function's pg_proc entry without changing its OID.
*/
static bool
func_up_to_date(PLpgSQL_function * func)
{
HeapTuple procTup;
bool result;
procTup = SearchSysCache(PROCOID,
ObjectIdGetDatum(func->fn_oid),
0, 0, 0);
if (!HeapTupleIsValid(procTup))
elog(ERROR, "plpgsql: cache lookup for proc %u failed",
func->fn_oid);
result = (func->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
func->fn_cmin == HeapTupleHeaderGetCmin(procTup->t_data));
ReleaseSysCache(procTup);
return result;
}

19
src/pl/plpgsql/src/plpgsql.h
View File

@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.36 2003/05/05 16:46:28 tgl Exp $
* $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.37 2003/07/01 21:47:09 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@ -487,6 +487,18 @@ typedef struct
} PLpgSQL_stmt_dynexecute;
typedef struct PLpgSQL_func_hashkey
{ /* Hash lookup key for functions */
Oid funcOid;
/*
* We include actual argument types in the hash key to support
* polymorphic PLpgSQL functions. Be careful that extra positions
* are zeroed!
*/
Oid argtypes[FUNC_MAX_ARGS];
} PLpgSQL_func_hashkey;
typedef struct PLpgSQL_function
{ /* Complete compiled function */
char *fn_name;
@ -494,6 +506,7 @@ typedef struct PLpgSQL_function
TransactionId fn_xmin;
CommandId fn_cmin;
int fn_functype;
PLpgSQL_func_hashkey *fn_hashkey; /* back-link to hashtable key */
Oid fn_rettype;
int fn_rettyplen;
@ -519,8 +532,6 @@ typedef struct PLpgSQL_function
int ndatums;
PLpgSQL_datum **datums;
PLpgSQL_stmt_block *action;
struct PLpgSQL_function *next; /* for chaining list of functions */
} PLpgSQL_function;
@ -588,7 +599,7 @@ extern PLpgSQL_function *plpgsql_curr_compile;
* Functions in pl_comp.c
* ----------
*/
extern PLpgSQL_function *plpgsql_compile(Oid fn_oid, int functype);
extern PLpgSQL_function *plpgsql_compile(FunctionCallInfo fcinfo);
extern int plpgsql_parse_word(char *word);
extern int plpgsql_parse_dblword(char *word);
extern int plpgsql_parse_tripword(char *word);