fix: Revert change in behavior for MariaDB and MySQL with regards to time zone assumptions for persisted timestamps

README.md

@@ -196,8 +196,10 @@ How often the scheduler checks the database for due executions. Default `10s`.<b
 The Scheduler assumes that columns for persisting timestamps persist `Instant`s, not `LocalDateTime`s,
  i.e. somehow tie the timestamp to a zone. However, some databases have limited support for such types
  (which has no zone information) or other quirks, making "always store in UTC" a better alternative.
-Currently, only PostgreSQL and Oracle rely on the database preserving time zone information,
-other databases store timestamps in UTC. **NB:** For backwards compatibility, the default behavior
+For such cases, use this setting to always store Instants in UTC.
+PostgreSQL and Oracle-schemas is tested to preserve zone-information. **MySQL** and **MariaDB**-schemas
+_does not_ and should use this setting.
+**NB:** For backwards compatibility, the default behavior
 for "unknown" databases is to assume the database preserves time zone. For "known" databases,
 see the class `AutodetectJdbcCustomization`.
 

db-scheduler-boot-starter/src/main/java/com/github/kagkarlsson/scheduler/boot/config/DbSchedulerProperties.java

@@ -68,11 +68,13 @@ public class DbSchedulerProperties {
   /** What polling-strategy to use. Valid values are: FETCH,LOCK_AND_FETCH */
   private PollingStrategyConfig.Type pollingStrategy =
       SchedulerBuilder.DEFAULT_POLLING_STRATEGY.type;
+
   /**
    * The limit at which more executions are fetched from the database after fetching a full batch.
    */
   private double pollingStrategyLowerLimitFractionOfThreads =
       SchedulerBuilder.DEFAULT_POLLING_STRATEGY.lowerLimitFractionOfThreads;
+
   /**
    * For Type=FETCH, the number of due executions fetched from the database in each batch.
    *

db-scheduler/src/main/java/com/github/kagkarlsson/scheduler/jdbc/AutodetectJdbcCustomization.java

@@ -27,6 +27,8 @@
 public class AutodetectJdbcCustomization implements JdbcCustomization {
 
   private static final Logger LOG = LoggerFactory.getLogger(AutodetectJdbcCustomization.class);
+  private static final Logger SILENCABLE_LOG =
+      LoggerFactory.getLogger(LOG.getName() + ".utc_warning");
   public static final String MICROSOFT_SQL_SERVER = "Microsoft SQL Server";
   public static final String POSTGRESQL = "PostgreSQL";
   public static final String ORACLE = "Oracle";
@@ -48,6 +50,9 @@ public AutodetectJdbcCustomization(DataSource dataSource, boolean persistTimesta
 
       if (databaseProductName.equals(MICROSOFT_SQL_SERVER)) {
         LOG.info("Using MSSQL jdbc-overrides.");
+        if (persistTimestampInUTC) {
+          LOG.info("Redundant 'persistTimestampInUTC' setting. MSSQL will always persist in UTC.");
+        }
         detectedCustomization = new MssqlJdbcCustomization(true);
       } else if (databaseProductName.equals(POSTGRESQL)) {
         LOG.info("Using PostgreSQL jdbc-overrides.");
@@ -57,25 +62,26 @@ public AutodetectJdbcCustomization(DataSource dataSource, boolean persistTimesta
         detectedCustomization = new OracleJdbcCustomization(persistTimestampInUTC);
       } else if (databaseProductName.contains(MARIADB)) {
         LOG.info("Using MariaDB jdbc-overrides.");
-        detectedCustomization = new MariaDBJdbcCustomization(true);
+        logWarningIfNotUTC("MariaDB", persistTimestampInUTC);
+        detectedCustomization = new MariaDBJdbcCustomization(persistTimestampInUTC);
       } else if (databaseProductName.contains(MYSQL)) {
         int databaseMajorVersion = c.getMetaData().getDatabaseMajorVersion();
         String dbVersion = c.getMetaData().getDatabaseProductVersion();
+        logWarningIfNotUTC("MySQL", persistTimestampInUTC);
         if (databaseMajorVersion >= 8) {
           LOG.info("Using MySQL jdbc-overrides version 8 and later. (v {})", dbVersion);
-          detectedCustomization = new MySQL8JdbcCustomization(true);
+          detectedCustomization = new MySQL8JdbcCustomization(persistTimestampInUTC);
         } else {
           LOG.info("Using MySQL jdbc-overrides for version older than 8. (v {})", dbVersion);
-          detectedCustomization = new MySQLJdbcCustomization(true);
+          detectedCustomization = new MySQLJdbcCustomization(persistTimestampInUTC);
         }
       } else {
         if (persistTimestampInUTC) {
           LOG.info(
               "No database-specific jdbc-overrides applied. Behavior overridden to always store "
                   + "timestamps in zone UTC");
         } else {
-          Logger silencableLogger = LoggerFactory.getLogger(LOG.getName() + ".utc_warning");
-          silencableLogger.warn(
+          SILENCABLE_LOG.warn(
               "No database-specific jdbc-overrides applied. Assuming time-related columns "
                   + "to be of type compatibe with 'TIMESTAMP WITH TIME ZONE', i.e. zone is persisted."
                   + " If not, consider overriding to always UTC via '.alwaysPersistTimestampInUTC()'.");
@@ -151,4 +157,18 @@ public String createSelectDueQuery(String tableName, int limit, String andCondit
   public String getName() {
     return jdbcCustomization.getName();
   }
+
+  private void logWarningIfNotUTC(String database, boolean persistTimestampInUTC) {
+    if (!persistTimestampInUTC) {
+      SILENCABLE_LOG.warn(
+          "{}-schema does not support persistent timezones. "
+              + "It is recommended to store time in UTC to avoid issues with for example DST. "
+              + "For first time users, use setting 'alwaysPersistTimestampInUtc' to achieve this. "
+              + "Users upgrading from a version prior to v14.0.0 can either silence this logger, "
+              + "or perform a controlled upgrade to UTC timestamps. All old instances "
+              + "of the scheduler must be stopped and timestamps migrated to UTC before starting "
+              + "again, using 'alwaysPersistTimestampInUtc=true'.",
+          database);
+    }
+  }
 }

db-scheduler/src/main/java/com/github/kagkarlsson/scheduler/jdbc/MariaDBJdbcCustomization.java

@@ -23,12 +23,6 @@ public class MariaDBJdbcCustomization extends DefaultJdbcCustomization {
 
   public MariaDBJdbcCustomization(boolean persistTimestampInUTC) {
     super(persistTimestampInUTC);
-    if (!persistTimestampInUTC) {
-      LOG.warn(
-          "{} does not support persistent timezones. "
-              + "It is recommended to store time in UTC to avoid issues with for example DST",
-          getClass().getName());
-    }
   }
 
   @Override

db-scheduler/src/main/java/com/github/kagkarlsson/scheduler/jdbc/MySQL8JdbcCustomization.java

@@ -23,12 +23,6 @@ public class MySQL8JdbcCustomization extends DefaultJdbcCustomization {
 
   public MySQL8JdbcCustomization(boolean persistTimestampInUTC) {
     super(persistTimestampInUTC);
-    if (!persistTimestampInUTC) {
-      LOG.warn(
-          "{} does not support persistent timezones. "
-              + "It is recommended to store time in UTC to avoid issues with for example DST",
-          getClass().getName());
-    }
   }
 
   @Override

db-scheduler/src/main/java/com/github/kagkarlsson/scheduler/jdbc/MySQLJdbcCustomization.java

@@ -21,12 +21,6 @@ public class MySQLJdbcCustomization extends DefaultJdbcCustomization {
 
   public MySQLJdbcCustomization(boolean persistTimestampInUTC) {
     super(persistTimestampInUTC);
-    if (!persistTimestampInUTC) {
-      LOG.warn(
-          "{} does not support persistent timezones. "
-              + "It is recommended to store time in UTC to avoid issues with for example DST",
-          getClass().getName());
-    }
   }
 
   @Override

db-scheduler/src/test/java/com/github/kagkarlsson/scheduler/SchedulerTest.java

@@ -39,6 +39,7 @@ public class SchedulerTest {
 
   @RegisterExtension
   public EmbeddedPostgresqlExtension postgres = new EmbeddedPostgresqlExtension();
+
   //    @RegisterExtension
   //        public ChangeLogLevelsExtension changeLogLevels = new ChangeLogLevelsExtension(
   //        new ChangeLogLevelsExtension.LogLevelOverride("com.github.kagkarlsson.scheduler",

db-scheduler/src/test/java/com/github/kagkarlsson/scheduler/compatibility/PostgresqlCompatibilityTest.java

@@ -11,6 +11,7 @@ public class PostgresqlCompatibilityTest extends CompatibilityTest {
 
   @RegisterExtension
   public EmbeddedPostgresqlExtension postgres = new EmbeddedPostgresqlExtension();
+
   //    Enable if test gets flaky!
   //    @RegisterExtension
   //    public ChangeLogLevelsExtension changeLogLevels = new ChangeLogLevelsExtension(

db-scheduler/src/test/java/com/github/kagkarlsson/scheduler/functional/ExecutorPoolTest.java

@@ -35,6 +35,7 @@ public class ExecutorPoolTest {
   public EmbeddedPostgresqlExtension postgres = new EmbeddedPostgresqlExtension();
 
   @RegisterExtension public StopSchedulerExtension stopScheduler = new StopSchedulerExtension();
+
   //    Enable if test gets flaky!
   //    @RegisterExtension
   //    public ChangeLogLevelsExtension changeLogLevels = new ChangeLogLevelsExtension(

pom.xml

@@ -281,15 +281,15 @@
 			<plugin>
 				<groupId>com.diffplug.spotless</groupId>
 				<artifactId>spotless-maven-plugin</artifactId>
-				<version>2.36.0</version>
+				<version>2.43.0</version>
 				<configuration>
 					<java>
 						<includes>
 							<include>src/main/java/**/*.java</include> <!-- Check application code -->
 							<include>src/test/java/**/*.java</include> <!-- Check application tests code -->
 						</includes>
 						<googleJavaFormat>
-							<version>1.16.0</version>
+							<version>1.17.0</version>
 							<style>GOOGLE</style>
 						</googleJavaFormat>
 						<importOrder />