Add pg_show_all_settings() support

BemiHQ · Dec 12, 2024 · 46a3767 · 46a3767
1 parent 9afc001
commit 46a3767
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Showing 5 changed files with 146 additions and 3 deletions.
diff --git a/src/main.go b/src/main.go
@@ -6,7 +6,7 @@ import (
 	"time"
 )
 
-const VERSION = "0.25.0"
+const VERSION = "0.25.1"
 
 func main() {
 	config := LoadConfig()

diff --git a/src/query_handler_test.go b/src/query_handler_test.go
@@ -24,6 +24,10 @@ func TestHandleQuery(t *testing.T) {
 			"description": {"quote_ident"},
 			"values":      {"\"fooBar\""},
 		},
+		"SELECT setting from pg_show_all_settings() WHERE name = 'default_null_order'": {
+			"description": {"setting"},
+			"values":      {"nulls_last"},
+		},
 		// pg_get_partkeydef
 		"SELECT pg_catalog.pg_get_partkeydef(c.oid) FROM pg_catalog.pg_class c LIMIT 1": {
 			"description": {"pg_get_partkeydef"},

diff --git a/src/query_parser_table.go b/src/query_parser_table.go
@@ -16,8 +16,9 @@ const (
 	PG_SCHEMA_INFORMATION_SCHEMA = "information_schema"
 	PG_TABLE_TABLES              = "tables"
 
-	PG_FUNCTION_PG_GET_KEYWORDS = "pg_get_keywords"
-	PG_FUNCTION_ARRAY_UPPER     = "array_upper"
+	PG_FUNCTION_PG_GET_KEYWORDS      = "pg_get_keywords"
+	PG_FUNCTION_ARRAY_UPPER          = "array_upper"
+	PG_FUNCTION_PG_SHOW_ALL_SETTINGS = "pg_show_all_settings"
 )
 
 type QueryParserTable struct {
@@ -267,6 +268,128 @@ func (parser *QueryParserTable) MakeArrayUpperNode(funcCallNode *pgQuery.FuncCal
 	).GetFuncCall()
 }
 
+// pg_show_all_settings()
+func (parser *QueryParserTable) IsPgShowAllSettingsFunction(node *pgQuery.Node) bool {
+	for _, funcNode := range node.GetRangeFunction().Functions {
+		for _, funcItemNode := range funcNode.GetList().Items {
+			funcCallNode := funcItemNode.GetFuncCall()
+			if funcCallNode == nil {
+				continue
+			}
+			if len(funcCallNode.Funcname) != 1 {
+				continue
+			}
+
+			function := funcCallNode.Funcname[0].GetString_().Sval
+			if function == PG_FUNCTION_PG_SHOW_ALL_SETTINGS {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+// pg_show_all_settings() -> duckdb_settings() mapped to pg format
+func (parser *QueryParserTable) MakePgShowAllSettingsNode(node *pgQuery.Node) *pgQuery.Node {
+	return &pgQuery.Node{
+		Node: &pgQuery.Node_RangeSubselect{
+			RangeSubselect: &pgQuery.RangeSubselect{
+				Subquery: &pgQuery.Node{
+					Node: &pgQuery.Node_SelectStmt{
+						SelectStmt: &pgQuery.SelectStmt{
+							TargetList: []*pgQuery.Node{
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("name")}, 0),
+									"name",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("value")}, 0),
+									"setting",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"unit",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("Settings", 0),
+									"category",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("description")}, 0),
+									"short_desc",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"extra_desc",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("scope")}, 0),
+									"context",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("input_type")}, 0),
+									"vartype",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("default", 0),
+									"source",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"min_val",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"max_val",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"enumvals",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("value")}, 0),
+									"boot_val",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("value")}, 0),
+									"reset_val",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("", 0),
+									"sourcefile",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("0", 0),
+									"sourceline",
+								),
+								parser.utils.MakeResTargetNode(
+									pgQuery.MakeAConstStrNode("f", 0),
+									"pending_restart",
+								),
+							},
+							FromClause: []*pgQuery.Node{
+								pgQuery.MakeSimpleRangeFunctionNode([]*pgQuery.Node{
+									pgQuery.MakeListNode([]*pgQuery.Node{
+										pgQuery.MakeFuncCallNode(
+											[]*pgQuery.Node{
+												pgQuery.MakeStrNode("duckdb_settings"),
+											},
+											nil,
+											0,
+										),
+									}),
+								}),
+							},
+						},
+					},
+				},
+				Alias: node.GetAlias(),
+			},
+		},
+	}
+}
+
 func (parser *QueryParserTable) isPgCatalogSchema(qSchemaTable QuerySchemaTable) bool {
 	return qSchemaTable.Schema == PG_SCHEMA_PG_CATALOG || qSchemaTable.Schema == ""
 }

diff --git a/src/query_parser_utils.go b/src/query_parser_utils.go
@@ -67,3 +67,14 @@ func (utils *QueryParserUtils) MakeAConstBoolNode(val bool) *pgQuery.Node {
 		},
 	}
 }
+
+func (utils *QueryParserUtils) MakeResTargetNode(val *pgQuery.Node, name string) *pgQuery.Node {
+	return &pgQuery.Node{
+		Node: &pgQuery.Node_ResTarget{
+			ResTarget: &pgQuery.ResTarget{
+				Name: name,
+				Val:  val,
+			},
+		},
+	}
+}
diff --git a/src/select_remapper_table.go b/src/select_remapper_table.go
@@ -103,6 +103,11 @@ func (remapper *SelectRemapperTable) RemapTableFunction(node *pgQuery.Node) *pgQ
 		return remapper.parserTable.MakePgGetKeywordsNode(node)
 	}
 
+	// pg_show_all_settings() -> duckdb_settings()
+	if remapper.parserTable.IsPgShowAllSettingsFunction(node) {
+		return remapper.parserTable.MakePgShowAllSettingsNode(node)
+	}
+
 	return node
 }