From 7e825f52895a9a7b49f7c7ae655cf31c657bf521 Mon Sep 17 00:00:00 2001
From: Colin Sharples <mote@ctg.co.nz>
Date: Fri, 29 Jul 2022 03:13:22 +1200
Subject: [PATCH] Set max fractional timestamp digits to 12 for all DB2
 editions (fix #2880) (#2892)

Set max fractional timestamp digits to 12 for all DB2 editions (#2880)

Co-authored-by: ctg <ctg@LAPTOP-50VTJSGN>
---
 .../database/core/AbstractDb2Database.java    | 19 ++++++++++++++++++-
 .../liquibase/database/core/Db2zDatabase.java | 11 +----------
 .../database/core/DB2DatabaseTest.java        |  6 ++++++
 .../database/core/DB2zDatabaseTest.java       |  5 +++++
 4 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/liquibase-core/src/main/java/liquibase/database/core/AbstractDb2Database.java b/liquibase-core/src/main/java/liquibase/database/core/AbstractDb2Database.java
index b47c4e8d89d..5004854cb6f 100644
--- a/liquibase-core/src/main/java/liquibase/database/core/AbstractDb2Database.java
+++ b/liquibase-core/src/main/java/liquibase/database/core/AbstractDb2Database.java
@@ -24,7 +24,9 @@
 
 public abstract class AbstractDb2Database extends AbstractJdbcDatabase {
 
-    public AbstractDb2Database() {
+    private static final int MAX_DB2_TIMESTAMP_FRACTIONAL_DIGITS = 12;
+
+	public AbstractDb2Database() {
         super.setCurrentDateTimeFunction("CURRENT TIMESTAMP");
         super.sequenceNextValueFunction = "NEXT VALUE FOR %s";
         super.sequenceCurrentValueFunction = "PREVIOUS VALUE FOR %s";
@@ -235,4 +237,19 @@ protected boolean mustQuoteObjectName(String objectName, Class<? extends Databas
     public CatalogAndSchema.CatalogAndSchemaCase getSchemaAndCatalogCase() {
         return CatalogAndSchema.CatalogAndSchemaCase.ORIGINAL_CASE;
     }
+
+	@Override
+	public int getMaxFractionalDigitsForTimestamp() {
+		try {
+			// See https://www.ibm.com/docs/en/db2/9.7?topic=enhancements-timestamp-data-type-allows-parameterized-precision
+			// Max precision for timestamp is 12 digits in all editions of DB from version 9.7 onwards
+			if (getDatabaseMajorVersion() > 9 || getDatabaseMajorVersion() == 9 && getDatabaseMinorVersion() >= 7) {
+				return MAX_DB2_TIMESTAMP_FRACTIONAL_DIGITS;
+			} else {
+				return super.getMaxFractionalDigitsForTimestamp();
+			} 
+		} catch (Exception e) {
+			return super.getMaxFractionalDigitsForTimestamp();
+		}
+	}
 }
diff --git a/liquibase-core/src/main/java/liquibase/database/core/Db2zDatabase.java b/liquibase-core/src/main/java/liquibase/database/core/Db2zDatabase.java
index c6955277ce2..bf6b89c9454 100644
--- a/liquibase-core/src/main/java/liquibase/database/core/Db2zDatabase.java
+++ b/liquibase-core/src/main/java/liquibase/database/core/Db2zDatabase.java
@@ -9,11 +9,7 @@
 
 public class Db2zDatabase extends AbstractDb2Database {
 	
-	// See https://www.ibm.com/support/knowledgecenter/en/SSEPEK_11.0.0/sqlref/src/tpc/db2z_limits.html#db2z_limits__limdt, 
-	// may not apply to older versions, caveat emptor 
-	private static final int MAX_DB2Z_TIMESTAMP_FRACTIONAL_DIGITS = 12;
-	
-    public Db2zDatabase() {
+	public Db2zDatabase() {
         super.setCurrentDateTimeFunction("CURRENT TIMESTAMP");
         super.sequenceNextValueFunction = "NEXT VALUE FOR %s";
         super.sequenceCurrentValueFunction = "PREVIOUS VALUE FOR %s";
@@ -51,9 +47,4 @@ public boolean isSystemObject(DatabaseObject example) {
     protected String getDefaultDatabaseProductName() {
         return "DB2/z";
     }
-
-    @Override
-    public int getMaxFractionalDigitsForTimestamp() {
-    	return MAX_DB2Z_TIMESTAMP_FRACTIONAL_DIGITS;
-    }
 }
diff --git a/liquibase-core/src/test/java/liquibase/database/core/DB2DatabaseTest.java b/liquibase-core/src/test/java/liquibase/database/core/DB2DatabaseTest.java
index 9546275e1a4..23ad7886fa5 100644
--- a/liquibase-core/src/test/java/liquibase/database/core/DB2DatabaseTest.java
+++ b/liquibase-core/src/test/java/liquibase/database/core/DB2DatabaseTest.java
@@ -16,4 +16,10 @@ public void testGetDefaultDriver() throws DatabaseException {
         }
     }
 
+    public void testMaxFractionDigits() {
+        Database database = new DB2Database();
+        assertEquals(12, database.getMaxFractionalDigitsForTimestamp());
+    }
+
+
 }
diff --git a/liquibase-core/src/test/java/liquibase/database/core/DB2zDatabaseTest.java b/liquibase-core/src/test/java/liquibase/database/core/DB2zDatabaseTest.java
index 9b3533f538d..6eecde644a0 100644
--- a/liquibase-core/src/test/java/liquibase/database/core/DB2zDatabaseTest.java
+++ b/liquibase-core/src/test/java/liquibase/database/core/DB2zDatabaseTest.java
@@ -16,4 +16,9 @@ public void testGetDefaultDriver() throws DatabaseException {
         }
     }
 
+    public void testMaxFractionDigits() {
+        Database database = new Db2zDatabase();
+        assertEquals(12, database.getMaxFractionalDigitsForTimestamp());
+    }
+
 }