From 02b45362dcb0a6df0cdb113e330d3c95450d5388 Mon Sep 17 00:00:00 2001
From: Gavin King <gavin@hibernate.org>
Date: Sat, 15 Nov 2025 10:08:42 +0100
Subject: [PATCH] HHH-19749/HHH-18860 fix to precision of double/float mapped
 to DECIMAL/NUMERIC

---
 .../type/descriptor/java/DoubleJavaType.java  | 20 ++++++-------------
 .../type/descriptor/java/FloatJavaType.java   | 19 ++++++------------
 2 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/DoubleJavaType.java b/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/DoubleJavaType.java
index fff166f2d591..3bf60f6c2497 100644
--- a/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/DoubleJavaType.java
+++ b/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/DoubleJavaType.java
@@ -15,9 +15,6 @@
 import org.hibernate.type.descriptor.jdbc.JdbcType;
 import org.hibernate.type.descriptor.jdbc.JdbcTypeIndicators;
 
-import static java.lang.Math.ceil;
-import static java.lang.Math.log;
-
 /**
  * Descriptor for {@link Double} handling.
  *
@@ -26,8 +23,6 @@
 public class DoubleJavaType extends AbstractClassJavaType<Double> implements
 		PrimitiveJavaType<Double> {
 	public static final DoubleJavaType INSTANCE = new DoubleJavaType();
-	//needed for converting precision from binary to decimal digits
-	private static final double LOG_BASE10OF2 = log(2)/log(10);
 
 	public DoubleJavaType() {
 		super( Double.class );
@@ -156,17 +151,14 @@ public long getDefaultSqlLength(Dialect dialect, JdbcType jdbcType) {
 
 	@Override
 	public int getDefaultSqlPrecision(Dialect dialect, JdbcType jdbcType) {
-		if ( jdbcType.isFloat() ) {
-			//this is the number of *binary* digits
-			//in a double-precision FP number
-			return dialect.getDoublePrecision();
-		}
-		else {
-			return Math.min( dialect.getDefaultDecimalPrecision(), (int) ceil( dialect.getDoublePrecision() * LOG_BASE10OF2 ) );
-		}
+		return jdbcType.isFloat()
+				// this is usually the number of *binary* digits
+				// in a double-precision FP number
+				? dialect.getDoublePrecision()
+				// this is the number of decimal digits in a Java double
+				: 17;
 	}
 
-
 	@Override
 	public <X> Double coerce(X value, CoercionContext coercionContext) {
 		if ( value == null ) {
diff --git a/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/FloatJavaType.java b/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/FloatJavaType.java
index e65e1a24deb6..4a6c6e9e8f5d 100644
--- a/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/FloatJavaType.java
+++ b/hibernate-core/src/main/java/org/hibernate/type/descriptor/java/FloatJavaType.java
@@ -15,9 +15,6 @@
 import org.hibernate.type.descriptor.jdbc.JdbcType;
 import org.hibernate.type.descriptor.jdbc.JdbcTypeIndicators;
 
-import static java.lang.Math.ceil;
-import static java.lang.Math.log;
-
 /**
  * Descriptor for {@link Float} handling.
  *
@@ -25,8 +22,6 @@
  */
 public class FloatJavaType extends AbstractClassJavaType<Float> implements PrimitiveJavaType<Float> {
 	public static final FloatJavaType INSTANCE = new FloatJavaType();
-	//needed for converting precision from binary to decimal digits
-	private static final double LOG_BASE10OF2 = log(2)/log(10);
 
 	public FloatJavaType() {
 		super( Float.class );
@@ -154,14 +149,12 @@ public long getDefaultSqlLength(Dialect dialect, JdbcType jdbcType) {
 
 	@Override
 	public int getDefaultSqlPrecision(Dialect dialect, JdbcType jdbcType) {
-		if ( jdbcType.isFloat() ) {
-			//this is the number of *binary* digits
-			//in a single-precision FP number
-			return dialect.getFloatPrecision();
-		}
-		else {
-			return Math.min( dialect.getDefaultDecimalPrecision(), (int) ceil( dialect.getFloatPrecision() * LOG_BASE10OF2 ) );
-		}
+		return jdbcType.isFloat()
+				// this is usually the number of *binary* digits
+				// in a single-precision FP number
+				? dialect.getFloatPrecision()
+				// this is the number of decimal digits in a Java float
+				: 8;
 	}
 
 	@Override