Fix decimal precision in database metadata

Author: alex268

jdbc/src/main/java/tech/ydb/jdbc/YdbConst.java

@@ -6,11 +6,7 @@ public final class YdbConst {
     public static final int UNKNOWN_SQL_TYPE = Integer.MIN_VALUE;
 
     public static final int SQL_KIND_PRIMITIVE = 10000;
-    public static final int SQL_KIND_DECIMAL = 1 << 15; // 32768
-
-    // YDB does not support types with custom precision yet
-    public static final int SQL_DECIMAL_DEFAULT_PRECISION = 22;
-    public static final int SQL_DECIMAL_DEFAULT_SCALE = 9;
+    public static final int SQL_KIND_DECIMAL = 1 << 14; // 16384
 
     // Built-in limits
     public static final int MAX_PRIMARY_KEY_SIZE = 1024 * 1024; // 1 MiB per index

jdbc/src/main/java/tech/ydb/jdbc/impl/YdbDatabaseMetaDataImpl.java

@@ -39,6 +39,7 @@
 import tech.ydb.table.description.TableIndex;
 import tech.ydb.table.result.ResultSetReader;
 import tech.ydb.table.settings.DescribeTableSettings;
+import tech.ydb.table.values.DecimalType;
 import tech.ydb.table.values.PrimitiveType;
 import tech.ydb.table.values.Type;
 
@@ -799,7 +800,14 @@ public ResultSet getColumns(String catalog, String schemaPattern, String tableNa
                     nullable = columnNoNulls;
                 }
 
-                int decimalDigits = type.getKind() == Type.Kind.DECIMAL ? YdbConst.SQL_DECIMAL_DEFAULT_PRECISION : 0;
+                int decimalDigits = 0;
+                if (type.getKind() == Type.Kind.DECIMAL) {
+                    if (type instanceof DecimalType) {
+                        decimalDigits = ((DecimalType) type).getPrecision();
+                    } else {
+                        decimalDigits = DecimalType.getDefault().getPrecision();
+                    }
+                }
 
                 rs.newRow()
                         .withTextValue("TABLE_NAME", tableName)
@@ -874,11 +882,17 @@ public ResultSet getBestRowIdentifier(String catalog, String schema, String tabl
         for (String key : description.getPrimaryKeys()) {
             TableColumn column = columnMap.get(key);
             Type type = column.getType();
+            int decimalDigits = 0;
             if (type.getKind() == Type.Kind.OPTIONAL) {
                 type = type.unwrapOptional();
             }
-
-            int decimalDigits = type.getKind() == Type.Kind.DECIMAL ? YdbConst.SQL_DECIMAL_DEFAULT_PRECISION : 0;
+            if (type.getKind() == Type.Kind.DECIMAL) {
+                if (type instanceof DecimalType) {
+                    decimalDigits = ((DecimalType) type).getPrecision();
+                } else {
+                    decimalDigits = DecimalType.getDefault().getPrecision();
+                }
+            }
 
             rs.newRow()
                     .withShortValue("SCOPE", (short) scope)
@@ -962,7 +976,15 @@ public ResultSet getTypeInfo() {
 
         for (Type type: YdbTypes.getAllDatabaseTypes()) {
             String literal = getLiteral(type);
-            int scale = type.getKind() == Type.Kind.DECIMAL ? YdbConst.SQL_DECIMAL_DEFAULT_SCALE : 0;
+            int scale = 0;
+            if (type.getKind() == Type.Kind.DECIMAL) {
+                if (type instanceof DecimalType) {
+                    scale = ((DecimalType) type).getScale();
+                } else {
+                    scale = DecimalType.getDefault().getScale();
+                }
+            }
+
             rs.newRow()
                     .withTextValue("TYPE_NAME", type.toString())
                     .withIntValue("DATA_TYPE", YdbTypes.toSqlType(type))

jdbc/src/main/java/tech/ydb/jdbc/impl/YdbTypes.java

@@ -245,7 +245,7 @@ private int getSqlPrecisionImpl(Type type) {
             case OPTIONAL:
                 return getSqlPrecisionImpl(type.unwrapOptional());
             case DECIMAL:
-                return 8 + 8;
+                return ((DecimalType) type).getPrecision();
             case PRIMITIVE:
                 return getSqlPrecisionImpl((PrimitiveType) type);
             default:

jdbc/src/test/java/tech/ydb/jdbc/impl/YdbDatabaseMetaDataImplTest.java

@@ -424,7 +424,7 @@ public void getTypeInfo() throws SQLException {
         rs.nextRow(name.eq("Timestamp"), type.eq(Types.TIMESTAMP), precision.eq(26), unsigned.eq(false)).assertAll();
         rs.nextRow(name.eq("Interval"), type.eq(Types.BIGINT), precision.eq(8), unsigned.eq(false)).assertAll();
 
-        rs.nextRow(name.eq("Decimal(22, 9)"), type.eq(Types.DECIMAL), precision.eq(16),
+        rs.nextRow(name.eq("Decimal(22, 9)"), type.eq(Types.DECIMAL), precision.eq(22),
                 unsigned.eq(false), fixedPrec.eq(true), minScale.eq(9), maxScale.eq(9)).assertAll();
 
         rs.assertNoRows();
@@ -616,7 +616,7 @@ public void getColumns() throws SQLException {
                 columnSize.eq(8), ordinal.eq(21)).assertAll();
 
         rs.nextRow(columnName.eq("c_Decimal"), dataType.eq(Types.DECIMAL), typeName.eq("Decimal(22, 9)"),
-                columnSize.eq(16), ordinal.eq(22), decimalDigits.eq(22)).assertAll();
+                columnSize.eq(22), ordinal.eq(22), decimalDigits.eq(22)).assertAll();
 
         rs.assertNoRows();