diff --git a/eco-api/src/main/java/com/willfp/eco/core/data/handlers/DataTypeSerializer.java b/eco-api/src/main/java/com/willfp/eco/core/data/handlers/DataTypeSerializer.java
index 78d54387..3f25946d 100644
--- a/eco-api/src/main/java/com/willfp/eco/core/data/handlers/DataTypeSerializer.java
+++ b/eco-api/src/main/java/com/willfp/eco/core/data/handlers/DataTypeSerializer.java
@@ -9,6 +9,8 @@ import java.util.UUID;
 /**
  * Handles data read/write for a {@link com.willfp.eco.core.data.keys.PersistentDataKeyType} for a specific
  * data handler.
+ *
+ * @param <T> The type of data.
  */
 public abstract class DataTypeSerializer<T> {
     /**
diff --git a/eco-api/src/main/java/com/willfp/eco/core/data/handlers/PersistentDataHandler.java b/eco-api/src/main/java/com/willfp/eco/core/data/handlers/PersistentDataHandler.java
index 7e8711cb..b22bb017 100644
--- a/eco-api/src/main/java/com/willfp/eco/core/data/handlers/PersistentDataHandler.java
+++ b/eco-api/src/main/java/com/willfp/eco/core/data/handlers/PersistentDataHandler.java
@@ -1,7 +1,9 @@
 package com.willfp.eco.core.data.handlers;
 
+import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.data.keys.PersistentDataKey;
 import com.willfp.eco.core.registry.Registrable;
+import org.bukkit.Bukkit;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -125,7 +127,10 @@ public abstract class PersistentDataHandler implements Registrable {
 
             for (PersistentDataKey<?> key : keys) {
                 Object value = read(uuid, key);
-                data.put(key, value);
+
+                if (value != null) {
+                    data.put(key, value);
+                }
             }
 
             profiles.add(new SerializedProfile(uuid, data));
@@ -151,13 +156,20 @@ public abstract class PersistentDataHandler implements Registrable {
     }
 
     /**
-     * Await outstanding writes.
+     * Save and shutdown the handler.
+     *
+     * @throws InterruptedException If the writes could not be awaited.
      */
-    public final void awaitOutstandingWrites() throws InterruptedException {
-        boolean success = executor.awaitTermination(2, TimeUnit.MINUTES);
+    public final void shutdown() throws InterruptedException {
+        doSave();
 
-        if (!success) {
-            throw new InterruptedException("Failed to await outstanding writes");
+        if (executor.isShutdown()) {
+            return;
+        }
+
+        executor.shutdown();
+        while (!executor.awaitTermination(2, TimeUnit.MINUTES)) {
+            // Wait
         }
     }
 
@@ -166,18 +178,4 @@ public abstract class PersistentDataHandler implements Registrable {
     public final String getID() {
         return id;
     }
-
-    @Override
-    public boolean equals(@NotNull final Object obj) {
-        if (!(obj instanceof PersistentDataHandler other)) {
-            return false;
-        }
-
-        return other.getClass().equals(this.getClass());
-    }
-
-    @Override
-    public int hashCode() {
-        return this.getClass().hashCode();
-    }
 }
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoSpigotPlugin.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoSpigotPlugin.kt
index 33a0c5ce..06924ccf 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoSpigotPlugin.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoSpigotPlugin.kt
@@ -148,7 +148,7 @@ import org.bukkit.inventory.ItemStack
 
 abstract class EcoSpigotPlugin : EcoPlugin() {
     abstract val dataYml: DataYml
-    protected abstract val profileHandler: ProfileHandler
+    abstract val profileHandler: ProfileHandler
     protected var bukkitAudiences: BukkitAudiences? = null
 
     init {
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/PersistentDataHandlers.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/PersistentDataHandlers.kt
index c3458fd2..dce85b56 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/PersistentDataHandlers.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/PersistentDataHandlers.kt
@@ -23,12 +23,12 @@ object PersistentDataHandlers: Registry<PersistentDataHandlerFactory>() {
 
         register(object : PersistentDataHandlerFactory("mysql") {
             override fun create(plugin: EcoSpigotPlugin) =
-                MySQLPersistentDataHandler(plugin, plugin.configYml.getSubsection("mysql"))
+                MySQLPersistentDataHandler(plugin.configYml.getSubsection("mysql"))
         })
 
         register(object : PersistentDataHandlerFactory("mongo") {
             override fun create(plugin: EcoSpigotPlugin) =
-                MongoPersistentDataHandler(plugin, plugin.configYml.getSubsection("mongodb"))
+                MongoPersistentDataHandler(plugin.configYml.getSubsection("mongodb"))
         })
     }
 }
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/LegacyMySQLPersistentDataHandler.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/LegacyMySQLPersistentDataHandler.kt
index d57574cf..037a6163 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/LegacyMySQLPersistentDataHandler.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/LegacyMySQLPersistentDataHandler.kt
@@ -21,7 +21,6 @@ import java.math.BigDecimal
 import java.util.UUID
 
 class LegacyMySQLPersistentDataHandler(
-    plugin: EcoSpigotPlugin,
     config: Config
 ) : PersistentDataHandler("legacy_mysql") {
     private val dataSource = HikariDataSource(HikariConfig().apply {
@@ -101,7 +100,7 @@ class LegacyMySQLPersistentDataHandler(
 
     object Factory: PersistentDataHandlerFactory("legacy_mysql") {
         override fun create(plugin: EcoSpigotPlugin): PersistentDataHandler {
-            return LegacyMySQLPersistentDataHandler(plugin, plugin.configYml.getSubsection("mysql"))
+            return LegacyMySQLPersistentDataHandler(plugin.configYml.getSubsection("mysql"))
         }
     }
 }
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MongoPersistentDataHandler.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MongoPersistentDataHandler.kt
index 2f63deac..d78894b8 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MongoPersistentDataHandler.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MongoPersistentDataHandler.kt
@@ -20,7 +20,6 @@ import java.math.BigDecimal
 import java.util.UUID
 
 class MongoPersistentDataHandler(
-    plugin: EcoSpigotPlugin,
     config: Config
 ) : PersistentDataHandler("mongo") {
     private val client = MongoClient.create(config.getString("url"))
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MySQLPersistentDataHandler.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MySQLPersistentDataHandler.kt
index 5ff9a4b7..13dd0930 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MySQLPersistentDataHandler.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/handlers/impl/MySQLPersistentDataHandler.kt
@@ -8,7 +8,6 @@ import com.willfp.eco.core.data.handlers.DataTypeSerializer
 import com.willfp.eco.core.data.handlers.PersistentDataHandler
 import com.willfp.eco.core.data.keys.PersistentDataKey
 import com.willfp.eco.core.data.keys.PersistentDataKeyType
-import com.willfp.eco.internal.spigot.EcoSpigotPlugin
 import com.zaxxer.hikari.HikariConfig
 import com.zaxxer.hikari.HikariDataSource
 import org.jetbrains.exposed.sql.Column
@@ -25,7 +24,6 @@ import java.math.BigDecimal
 import java.util.UUID
 
 class MySQLPersistentDataHandler(
-    plugin: EcoSpigotPlugin,
     config: Config
 ) : PersistentDataHandler("mysql") {
     private val dataSource = HikariDataSource(HikariConfig().apply {
@@ -48,32 +46,32 @@ class MySQLPersistentDataHandler(
             override val table = object : KeyTable<String>("string") {
                 override val value = varchar("value", 128)
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.BOOLEAN.registerSerializer(this, object : DirectStoreSerializer<Boolean>() {
             override val table = object : KeyTable<Boolean>("boolean") {
                 override val value = bool("value")
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.INT.registerSerializer(this, object : DirectStoreSerializer<Int>() {
             override val table = object : KeyTable<Int>("int") {
                 override val value = integer("value")
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.DOUBLE.registerSerializer(this, object : DirectStoreSerializer<Double>() {
             override val table = object : KeyTable<Double>("double") {
                 override val value = double("value")
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.BIG_DECIMAL.registerSerializer(this, object : DirectStoreSerializer<BigDecimal>() {
             override val table = object : KeyTable<BigDecimal>("big_decimal") {
                 // 34 digits of precision, 4 digits of scale
                 override val value = decimal("value", 34, 4)
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.CONFIG.registerSerializer(this, object : SingleValueSerializer<Config, String>() {
             override val table = object : KeyTable<String>("config") {
@@ -92,13 +90,13 @@ class MySQLPersistentDataHandler(
                     Configs.fromMap(value.toMap(), ConfigType.JSON).toPlaintext()
                 }
             }
-        })
+        }.createTable())
 
         PersistentDataKeyType.STRING_LIST.registerSerializer(this, object : MultiValueSerializer<String>() {
             override val table = object : ListKeyTable<String>("string_list") {
                 override val value = varchar("value", 128)
             }
-        })
+        }.createTable())
     }
 
     override fun getSavedUUIDs(): Set<UUID> {
@@ -115,22 +113,24 @@ class MySQLPersistentDataHandler(
     private abstract inner class MySQLSerializer<T : Any> : DataTypeSerializer<T>() {
         protected abstract val table: ProfileTable
 
-        init {
-            transaction(database) {
-                SchemaUtils.create(table)
-            }
-        }
-
         fun getSavedUUIDs(): Set<UUID> {
             return transaction(database) {
                 table.selectAll().map { it[table.uuid] }.toSet()
             }
         }
+
+        fun createTable(): MySQLSerializer<T> {
+            transaction(database) {
+                SchemaUtils.create(table)
+            }
+
+            return this
+        }
     }
 
     // T is the key type
     // S is the stored value type
-    private abstract inner class SingleValueSerializer<T : Any, S: Any> : MySQLSerializer<T>() {
+    private abstract inner class SingleValueSerializer<T : Any, S : Any> : MySQLSerializer<T>() {
         abstract override val table: KeyTable<S>
 
         abstract fun convertToStored(value: T): S
@@ -148,17 +148,21 @@ class MySQLPersistentDataHandler(
         }
 
         override fun writeAsync(uuid: UUID, key: PersistentDataKey<T>, value: T) {
-            transaction(database) {
-                table.insert {
-                    it[table.uuid] = uuid
-                    it[table.key] = key.key.toString()
-                    it[table.value] = convertToStored(value)
+            withRetries {
+                transaction(database) {
+                    table.deleteWhere { (table.uuid eq uuid) and (table.key eq key.key.toString()) }
+
+                    table.insert {
+                        it[table.uuid] = uuid
+                        it[table.key] = key.key.toString()
+                        it[table.value] = convertToStored(value)
+                    }
                 }
             }
         }
     }
 
-    private abstract inner class DirectStoreSerializer<T: Any> : SingleValueSerializer<T, T>() {
+    private abstract inner class DirectStoreSerializer<T : Any> : SingleValueSerializer<T, T>() {
         override fun convertToStored(value: T): T {
             return value
         }
@@ -168,7 +172,7 @@ class MySQLPersistentDataHandler(
         }
     }
 
-    private abstract inner class MultiValueSerializer<T: Any> : MySQLSerializer<List<T>>() {
+    private abstract inner class MultiValueSerializer<T : Any> : MySQLSerializer<List<T>>() {
         abstract override val table: ListKeyTable<T>
 
         override fun readAsync(uuid: UUID, key: PersistentDataKey<List<T>>): List<T>? {
@@ -182,15 +186,17 @@ class MySQLPersistentDataHandler(
         }
 
         override fun writeAsync(uuid: UUID, key: PersistentDataKey<List<T>>, value: List<T>) {
-            transaction(database) {
-                table.deleteWhere { (table.uuid eq uuid) and (table.key eq key.key.toString()) }
+            withRetries {
+                transaction(database) {
+                    table.deleteWhere { (table.uuid eq uuid) and (table.key eq key.key.toString()) }
 
-                value.forEachIndexed { index, t ->
-                    table.insert {
-                        it[table.uuid] = uuid
-                        it[table.key] = key.key.toString()
-                        it[table.index] = index
-                        it[table.value] = t
+                    value.forEachIndexed { index, t ->
+                        table.insert {
+                            it[table.uuid] = uuid
+                            it[table.key] = key.key.toString()
+                            it[table.index] = index
+                            it[table.value] = t
+                        }
                     }
                 }
             }
@@ -208,7 +214,7 @@ class MySQLPersistentDataHandler(
         override val primaryKey = PrimaryKey(uuid, key)
 
         init {
-            uniqueIndex()
+            uniqueIndex(uuid, key)
         }
     }
 
@@ -220,7 +226,21 @@ class MySQLPersistentDataHandler(
         override val primaryKey = PrimaryKey(uuid, key, index)
 
         init {
-            uniqueIndex()
+            uniqueIndex(uuid, key, index)
+        }
+    }
+
+    private inline fun <T> withRetries(action: () -> T): T {
+        var retries = 0
+        while (true) {
+            try {
+                return action()
+            } catch (e: Exception) {
+                if (retries >= 3) {
+                    throw e
+                }
+                retries++
+            }
         }
     }
 }
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/profiles/ProfileHandler.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/profiles/ProfileHandler.kt
index 9b9c6469..fb5b9903 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/profiles/ProfileHandler.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/profiles/ProfileHandler.kt
@@ -6,6 +6,7 @@ import com.willfp.eco.internal.spigot.data.KeyRegistry
 import com.willfp.eco.internal.spigot.data.handlers.PersistentDataHandlerFactory
 import com.willfp.eco.internal.spigot.data.handlers.PersistentDataHandlers
 import com.willfp.eco.internal.spigot.data.handlers.impl.LegacyMySQLPersistentDataHandler
+import com.willfp.eco.internal.spigot.data.handlers.impl.MySQLPersistentDataHandler
 import com.willfp.eco.internal.spigot.data.handlers.impl.YamlPersistentDataHandler
 import com.willfp.eco.internal.spigot.data.profiles.impl.EcoPlayerProfile
 import com.willfp.eco.internal.spigot.data.profiles.impl.EcoProfile
@@ -17,7 +18,7 @@ import java.util.concurrent.ConcurrentHashMap
 class ProfileHandler(
     private val plugin: EcoSpigotPlugin
 ) {
-    private val handlerId = plugin.dataYml.getString("data-handler")
+    private val handlerId = plugin.configYml.getString("data-handler")
 
     val localHandler = YamlPersistentDataHandler(plugin)
     val defaultHandler = PersistentDataHandlers[handlerId]
@@ -44,11 +45,8 @@ class ProfileHandler(
     }
 
     fun save() {
-        localHandler.save()
-        defaultHandler.save()
-
-        localHandler.awaitOutstandingWrites()
-        defaultHandler.awaitOutstandingWrites()
+        localHandler.shutdown()
+        defaultHandler.shutdown()
     }
 
     fun migrateIfNecessary(): Boolean {
@@ -56,28 +54,25 @@ class ProfileHandler(
             return false
         }
 
+        // First install
         if (!plugin.dataYml.has("previous-handler")) {
             plugin.dataYml.set("previous-handler", defaultHandler.id)
+            plugin.dataYml.set("legacy-mysql-migrated", true)
             plugin.dataYml.save()
             return false
         }
 
-        if (defaultHandler.id == "mysql" && !plugin.dataYml.getBool("legacy-mysql-migrated")) {
-            plugin.logger.info("eco has detected a legacy MySQL database. Migrating to new MySQL database...")
-            scheduleMigration(LegacyMySQLPersistentDataHandler.Factory)
-
-            plugin.dataYml.set("legacy-mysql-migrated", true)
-            plugin.dataYml.save()
+        val previousHandlerId = plugin.dataYml.getString("previous-handler").lowercase()
+        if (previousHandlerId != defaultHandler.id) {
+            val fromFactory = PersistentDataHandlers[previousHandlerId] ?: return false
+            scheduleMigration(fromFactory)
 
             return true
         }
 
-
-        val previousHandlerId = plugin.dataYml.getString("previous-handler")
-        if (previousHandlerId != defaultHandler.id) {
-            val fromFactory = PersistentDataHandlers[previousHandlerId] ?: return false
-
-            scheduleMigration(fromFactory)
+        if (defaultHandler is MySQLPersistentDataHandler && !plugin.dataYml.getBool("legacy-mysql-migrated")) {
+            plugin.logger.info("eco has detected a legacy MySQL database. Migrating to new MySQL database...")
+            scheduleMigration(LegacyMySQLPersistentDataHandler.Factory)
 
             return true
         }
@@ -91,12 +86,15 @@ class ProfileHandler(
         // Run after 5 ticks to allow plugins to load their data keys
         plugin.scheduler.runLater(5) {
             doMigrate(fromFactory)
+
+            plugin.dataYml.set("legacy-mysql-migrated", true)
+            plugin.dataYml.save()
         }
     }
 
     private fun doMigrate(fromFactory: PersistentDataHandlerFactory) {
         plugin.logger.info("eco has detected a change in data handler")
-        plugin.logger.info("${fromFactory.id} --> $handlerId")
+        plugin.logger.info("${fromFactory.id} --> ${defaultHandler.id}")
         plugin.logger.info("This will take a while! Players will not be able to join during this time.")
 
         val fromHandler = fromFactory.create(plugin)
@@ -114,7 +112,7 @@ class ProfileHandler(
         }
 
         plugin.logger.info("Profile writes submitted! Waiting for completion...")
-        toHandler.awaitOutstandingWrites()
+        toHandler.shutdown()
 
         plugin.logger.info("Updating previous handler...")
         plugin.dataYml.set("previous-handler", handlerId)
diff --git a/eco-core/core-plugin/src/main/resources/config.yml b/eco-core/core-plugin/src/main/resources/config.yml
index cde16fad..4a6640f5 100644
--- a/eco-core/core-plugin/src/main/resources/config.yml
+++ b/eco-core/core-plugin/src/main/resources/config.yml
@@ -6,8 +6,8 @@
 
 # How player/server data is saved:
 # yaml - Stored in data.yml: Good option for single-node servers (i.e. no BungeeCord/Velocity)
-# mongo - If you're running on a network (Bungee/Velocity), you should use MongoDB if you can.
-# mysql - The alternative to MongoDB. Because of how eco data works, MongoDB is the best option; but use this if you can't.
+# mysql - Standard database, great option for multi-node servers (i.e. BungeeCord/Velocity)
+# mongo - Alternative database, may suit some servers better
 data-handler: yaml
 
 # If data should be migrated automatically when changing data handler.