!2555 优化内置函数（Internal Language实现）的查找方式

Merge pull request !2555 from april01xxx/dev_005_fmgr_lookup

src/common/backend/catalog/builtin_funcs.ini

@@ -7605,7 +7605,7 @@
     ),
     AddFuncGroup(
         "pg_cancel_session", 1,
-        AddBuiltinFunc(_0(3991), _1("pg_cancel_session"), _2(2), _3(true), _4(false), _5(pg_cancel_session), _6(16), _7(PG_CATALOG_NAMESPACE), _8(BOOTSTRAP_SUPERUSERID), _9(INTERNALlanguageId), _10(1), _11(0), _12(0), _13(0), _14(false), _15(false), _16(false), _17(false), _18('v'), _19(0), _20(2, 20, 20), _21(NULL), _22(NULL), _23(NULL), _24(NULL), _25("pg_cancel_session"), _26(NULL), _27(NULL), _28(NULL), _29(0), _30(false), _31(NULL), _32(false), _33(NULL))
+        AddBuiltinFunc(_0(3991), _1("pg_cancel_session"), _2(2), _3(true), _4(false), _5(pg_cancel_session), _6(16), _7(PG_CATALOG_NAMESPACE), _8(BOOTSTRAP_SUPERUSERID), _9(INTERNALlanguageId), _10(1), _11(0), _12(0), _13(0), _14(false), _15(false), _16(false), _17(false), _18('v'), _19(0), _20(2, 20, 20), _21(NULL), _22(NULL), _23(NULL), _24(NULL), _25("pg_cancel_session"), _26(NULL), _27(NULL), _28(NULL), _29(0), _30(false), _31(NULL), _32(false), _33(NULL), _34('f'), _35(NULL),  _36(0), _37(false), _38(NULL), _39(NULL), _40(0))
     ),
     AddFuncGroup(
         "pg_cbm_force_track", 1, 

src/common/backend/utils/Gen_fmgrtab.pl

@@ -86,7 +86,7 @@ my $prorettype; #[6]
 		
 foreach my $row (@{ $catalog{builtindata} })
 {
-	if ($row =~ /_0\(([0-9A-Z]+)\),\s+_1\(\"(\S+)\"\),\s+_2\((\d+)\),\s+_3\((\w+)\),\s+_4\((\w+)\),\s+.+?_6\((\d+)\),.+?_25\(\"(\w+)\"\),/)
+	if ($row =~ /_0\(([0-9A-Z_]+)\),\s+_1\(\"(\S+)\"\),\s+_2\((\d+)\),\s+_3\((\w+)\),\s+_4\((\w+)\),\s+.+?_6\((\w+)\),.+?_9\(INTERNALlanguageId\),.+?_25\(\"(.+?)\"\),/)
 	{
 		$foid = $1;
 		$funcName = $2;
@@ -218,12 +218,58 @@ foreach my $s (sort { $a->{proname} cmp $b->{proname} } @fmgr)
 
 # Create the fmgr_builtins table
 print T "\nconst FmgrBuiltin fmgr_builtins[] = {\n";
+my @fmgr_builtin_oid_index;
+my $last_builtin_oid = 0;
 foreach my $s (sort { $a->{prosrc} cmp $b->{prosrc} } @fmgr)
 {
 	print T
-"  { $s->{oid}, \"$s->{prosrc}\", $s->{nargs}, $s->{strict}, $s->{retset}, $s->{prosrc}, $s->{prorettype} },\n";
-	$nfmgrfuncs = $nfmgrfuncs + 1;
+"  { $s->{oid}, \"$s->{prosrc}\", $s->{nargs}, $s->{strict}, $s->{retset}, $s->{prosrc}, $s->{prorettype} }";
+
+	$fmgr_builtin_oid_index[$s->{oid}] = $nfmgrfuncs++;
+	if ($nfmgrfuncs <= $#fmgr)
+	{
+		print T ",\n";
+	}
+	else
+	{
+		print T "\n";
+	}
+	$last_builtin_oid = $s->{oid};
 }
+print T "};\n";
+
+printf T qq|
+const int fmgr_nbuiltins = (sizeof(fmgr_builtins) / sizeof(FmgrBuiltin));
+
+const Oid fmgr_last_builtin_oid = %u;
+|, $last_builtin_oid;
+
+# Create fmgr_builtin_oid_index table.
+printf T qq|
+const uint16 fmgr_builtin_oid_index[%u] = {
+|, $last_builtin_oid + 1;
+
+for (my $i = 0; $i <= $last_builtin_oid; $i++)
+{
+	my $oid = $fmgr_builtin_oid_index[$i];
+
+	# fmgr_builtin_oid_index is sparse, map nonexistent functions to
+	# InvalidOidBuiltinMapping
+	if (not defined $oid)
+	{
+		$oid = 'InvalidOidBuiltinMapping';
+	}
+
+	if ($i == $last_builtin_oid)
+	{
+		print T "  $oid\n";
+	}
+	else
+	{
+		print T "  $oid,\n";
+	}
+}
+print T "};\n";
 
 print H "\n#define nBuiltinFuncs  $nfuncs\n";
 print H "\n#define NFMGRFUNCS  $nfmgrfuncs\n";
@@ -232,17 +278,6 @@ print H "\n#define NFMGRFUNCS  $nfmgrfuncs\n";
 # And add the file footers.
 print H "\n#endif /* FMGROIDS_H */\n";
 
-print T
-qq|  /* dummy entry is easier than getting rid of comma after last real one */
-  /* (not that there has ever been anything wrong with *having* a
-     comma after the last field in an array initializer) */
-  { 0, NULL, 0, false, false, NULL, InvalidOid}
-};
-
-/* Note fmgr_nbuiltins excludes the dummy entry */
-const int fmgr_nbuiltins = (sizeof(fmgr_builtins) / sizeof(FmgrBuiltin)) - 1;
-|;
-
 close(H);
 close(T);
 close(B);

src/common/backend/utils/fmgr/fmgr.cpp

@@ -171,11 +171,21 @@ extern char* get_language_name(Oid languageOid);
 
 const FmgrBuiltin* fmgr_isbuiltin(Oid id)
 {
-    const Builtin_func*  func = SearchBuiltinFuncByOid(id);
-    if (func == NULL)
+    uint16      index;
+
+    /* fast lookup only possible if original oid still assigned */
+    if (id > fmgr_last_builtin_oid)
         return NULL;
-    else
-        return (func->prolang != INTERNALlanguageId) ? NULL : (const FmgrBuiltin*)func;
+
+    /*
+     * Lookup function data. If there's a miss in that range it's likely a
+     * nonexistent function, returning NULL here will trigger an ERROR later.
+     */
+    index = fmgr_builtin_oid_index[id];
+    if (index == InvalidOidBuiltinMapping)
+        return NULL;
+
+    return &fmgr_builtins[index];
 }
 
 /*

src/include/utils/fmgrtab.h

@@ -226,8 +226,18 @@ extern FuncGroup g_func_groups[];
 
 extern const int g_nfuncgroups; /* number of function groups */
 
+extern const Oid fmgr_last_builtin_oid; /* highest function OID in table */
+
 void initBuiltinFuncs();
 
 const FuncGroup* SearchBuiltinFuncByName(const char* funcname);
 const Builtin_func* SearchBuiltinFuncByOid(Oid id);
+
+/*
+ * Mapping from a builtin function's oid to the index in the fmgr_builtins
+ * array.
+ */
+#define InvalidOidBuiltinMapping UINT16_MAX
+extern const uint16 fmgr_builtin_oid_index[];
+
 #endif /* FMGRTAB_H */