Return the actual database name from pg_catalog.pg_database

BemiHQ · Dec 18, 2024 · 133ce1e · 133ce1e
1 parent 3987690
commit 133ce1e
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Showing 5 changed files with 38 additions and 105 deletions.
diff --git a/README.md b/README.md
@@ -51,7 +51,7 @@ Sync data from a Postgres database:
 ./bemidb --pg-database-url postgres://postgres:postgres@localhost:5432/dbname sync
 ```
 
-Run BemiDB database:
+Then run BemiDB database:
 
 ```sh
 ./bemidb start
@@ -61,7 +61,7 @@ Run Postgres queries on top of the BemiDB database:
 
 ```sh
 # List all tables
-psql postgres://localhost:54321/bemidb -c "SELECT * FROM information_schema.tables"
+psql postgres://localhost:54321/bemidb -c "SELECT table_schema, table_name FROM information_schema.tables"
 
 # Query a table
 psql postgres://localhost:54321/bemidb -c "SELECT COUNT(*) FROM [table_name]"
@@ -294,7 +294,6 @@ SELECT * FROM [TABLE] WHERE [JSON_COLUMN]->>'[JSON_KEY]' = '[JSON_VALUE]';
 - [ ] Iceberg table compaction and partitioning.
 - [ ] Cache layer for frequently accessed data.
 - [ ] Materialized views.
-- [ ] Support for custom S3-compatible endpoints.
 
 ## Alternatives
 

diff --git a/src/main.go b/src/main.go
@@ -6,7 +6,7 @@ import (
 	"time"
 )
 
-const VERSION = "0.27.2"
+const VERSION = "0.28.0"
 
 func main() {
 	config := LoadConfig()

diff --git a/src/query_handler_test.go b/src/query_handler_test.go
@@ -70,7 +70,7 @@ func TestHandleQuery(t *testing.T) {
 		},
 		"SELECT oid, datname, datdba FROM pg_catalog.pg_database where oid = 1146": {
 			"description": {"oid", "datname", "datdba"},
-			"values":      {"1146", "memory", ""},
+			"values":      {"1146", "bemidb", "10"},
 		},
 		"SELECT * FROM pg_catalog.pg_stat_gssapi": {
 			"description": {"pid", "gss_authenticated", "principal", "encrypted", "credentials_delegated"},

diff --git a/src/query_parser_table.go b/src/query_parser_table.go
@@ -91,107 +91,21 @@ func (parser *QueryParserTable) MakePgExtensionNode(alias string) *pgQuery.Node
 }
 
 // pg_catalog.pg_database -> VALUES(values...) t(columns...)
-func (parser *QueryParserTable) MakePgDatabaseNode(alias string) *pgQuery.Node {
-	targetList := []*pgQuery.Node{
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"oid",
-			pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("oid")}, 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datname",
-			pgQuery.MakeColumnRefNode([]*pgQuery.Node{pgQuery.MakeStrNode("datname")}, 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datdba",
-			pgQuery.MakeAConstStrNode("", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"encoding",
-			pgQuery.MakeAConstStrNode("6", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datlocprovider",
-			pgQuery.MakeAConstStrNode("c", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datistemplate",
-			pgQuery.MakeAConstStrNode("f", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datallowconn",
-			pgQuery.MakeAConstStrNode("t", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datconnlimit",
-			pgQuery.MakeAConstStrNode("-1", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datfrozenxid",
-			pgQuery.MakeAConstStrNode("722", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datminmxid",
-			pgQuery.MakeAConstStrNode("1", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"dattablespace",
-			pgQuery.MakeAConstStrNode("1663", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datcollate",
-			pgQuery.MakeAConstStrNode("en_US.UTF-8", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datctype",
-			pgQuery.MakeAConstStrNode("en_US.UTF-8", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"daticulocale",
-			pgQuery.MakeAConstStrNode("", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"daticurules",
-			pgQuery.MakeAConstStrNode("", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datcollversion",
-			pgQuery.MakeAConstStrNode("", 0),
-			0,
-		),
-		pgQuery.MakeResTargetNodeWithNameAndVal(
-			"datacl",
-			pgQuery.MakeAConstStrNode("", 0),
-			0,
-		),
-	}
+func (parser *QueryParserTable) MakePgDatabaseNode(database string, alias string) *pgQuery.Node {
+	columns := PG_DATABASE_VALUE_BY_COLUMN.Keys()
+	staticRowValues := PG_DATABASE_VALUE_BY_COLUMN.Values()
 
-	fromClause := &pgQuery.Node{
-		Node: &pgQuery.Node_RangeVar{
-			RangeVar: &pgQuery.RangeVar{
-				Schemaname:     "pg_catalog",
-				Relname:        "pg_database",
-				Inh:            true,
-				Relpersistence: "p",
-			},
-		},
+	var rowsValues [][]string
+	rowValues := make([]string, len(staticRowValues))
+	copy(rowValues, staticRowValues)
+	for i, column := range columns {
+		if column == "datname" {
+			rowValues[i] = database
+		}
 	}
+	rowsValues = append(rowsValues, rowValues)
 
-	return parser.utils.MakeSubselectFromNode(targetList, fromClause, alias)
+	return parser.utils.MakeSubselectWithRowsNode(columns, rowsValues, alias)
 }
 
 // System pg_* tables
@@ -628,6 +542,26 @@ var PG_EXTENSION_VALUE_BY_COLUMN = NewOrderedMap([][]string{
 	{"extcondition", "NULL"},
 })
 
+var PG_DATABASE_VALUE_BY_COLUMN = NewOrderedMap([][]string{
+	{"oid", "1146"},
+	{"datname", "bemidb"},
+	{"datdba", "10"},
+	{"encoding", "6"},
+	{"datlocprovider", "c"},
+	{"datistemplate", "FALSE"},
+	{"datallowconn", "TRUE"},
+	{"datconnlimit", "-1"},
+	{"datfrozenxid", "722"},
+	{"datminmxid", "1"},
+	{"dattablespace", "1663"},
+	{"datcollate", "en_US.UTF-8"},
+	{"datctype", "en_US.UTF-8"},
+	{"daticulocale", "NULL"},
+	{"daticurules", "NULL"},
+	{"datcollversion", "NULL"},
+	{"datacl", "NULL"},
+})
+
 type DuckDBKeyword struct {
 	word     string
 	category string

diff --git a/src/select_remapper_table.go b/src/select_remapper_table.go
@@ -84,8 +84,8 @@ func (remapper *SelectRemapperTable) RemapTable(node *pgQuery.Node) *pgQuery.Nod
 			tableNode := parser.MakeEmptyTableNode(PG_REPLICATION_SLOTS_COLUMNS, qSchemaTable.Alias)
 			return remapper.overrideTable(node, tableNode)
 		case PG_TABLE_PG_DATABASE:
-			// pg_catalog.pg_database -> extend with additional Postgres columns
-			tableNode := parser.MakePgDatabaseNode(qSchemaTable.Alias)
+			// pg_catalog.pg_database -> return hard-coded database info
+			tableNode := parser.MakePgDatabaseNode(remapper.config.Database, qSchemaTable.Alias)
 			return remapper.overrideTable(node, tableNode)
 		case PG_TABLE_PG_STAT_GSSAPI:
 			// pg_catalog.pg_stat_gssapi -> return nothing