MyCATApache/Mycat-Server · error · ConfigException

new & old table config is not equal!

Error message

new & old table config is not equal!

What it means

When migrating all tables under a schema (no explicit table list), ConfigComparer requires the set of table names to be identical in the old and new configurations. If the key sets differ, a ConfigException is thrown because safe migration cannot map tables that exist in only one config.

Solutions

  1. Diff the <table> entries of the schema between old and new schema.xml and make the table sets identical.
  2. If a table should not be migrated, list only the intended tables explicitly in tablesFile.properties instead of migrating all.
  3. Fix misspelled table names so both configs match.
  4. Remove leftover table definitions from whichever config should not have them.

Example fix

// before: new config missing table
old: order_main, order_detail ; new: order_main
// after
new schema.xml also defines <table name="order_detail" ...>
Defensive patterns

Strategy: validation

Validate before calling

Set<String> oldT = oldSchema.getTables().keySet();
Set<String> newT = newSchema.getTables().keySet();
if (!oldT.equals(newT)) {
    Set<String> diff = new HashSet<>(oldT); diff.removeAll(newT);
    Set<String> diff2 = new HashSet<>(newT); diff2.removeAll(oldT);
    throw new IllegalStateException("table set mismatch; only-old=" + diff + " only-new=" + diff2);
}

Try / catch

try {
    comparer.compare();
} catch (ConfigException e) {
    if (e.getMessage().contains("new & old table config is not equal")) {
        // diff <table> entries for the schema, align them, or list tables explicitly
    }
    throw e;
}

Prevention

When it happens

Trigger: Migrating a whole schema (tables entry empty) where the old schema.xml defines tables that the new schema.xml does not, or vice versa — e.g. a table was added or removed between configurations.

Common situations: Adding a new sharding table to the new config but not the old; removing a table in the new config; copy of schema.xml not kept in sync; typo in a table name in either config.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of MyCATApache/Mycat-Server@65f8d8beb7 (2026-09-11). Data as JSON: /api/errors/6c0b49bdc17411a5. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/io/mycat/util/dataMigrator/ConfigComparer.java:153

		if(!DataMigratorUtil.isKeyExistIgnoreCase(newSchemas,schemaName)){
			throw new ConfigException("newSchema:"+schemaName+" is not exists!");
		}
		Map<String, TableConfig> oldTables =  DataMigratorUtil.getValueIgnoreCase(oldSchemas, schemaName).getTables();
		Map<String, TableConfig> newTables = DataMigratorUtil.getValueIgnoreCase(newSchemas, schemaName).getTables();
		if(tables.length>0){
			//指定schema下的表进行迁移
			for(int i =0;i<tables.length;i++){
				TableConfig oldTable =  DataMigratorUtil.getValueIgnoreCase(oldTables,tables[i]);
				TableConfig newTable = DataMigratorUtil.getValueIgnoreCase(newTables,tables[i]);
				loadMigratorTable(oldTable, newTable,schemaName,tables[i]);
			}
		}else{
			//迁移schema下所有的表
			//校验新旧schema中的table配置是否一致
			Set<String> oldSet = oldTables.keySet();
			Set<String> newSet = newTables.keySet();
			if(!oldSet.equals(newSet)){
				throw new ConfigException("new & old table config is not equal!");
			}
			for(String tableName:oldSet){
				TableConfig oldTable = oldTables.get(tableName);
				TableConfig newTable = newTables.get(tableName);
				loadMigratorTable(oldTable, newTable,schemaName,tableName);
			}
		}
		
	}
	
	
	
	private void loadMigratorTable(TableConfig oldTable,TableConfig newTable,String schemaName,String tableName){
		//禁止配置非拆分表
		if(oldTable == null || newTable == null){
			throw new ConfigException("please check tableFile.properties,make sure "+schemaName+":"+tableName+" is sharding table ");
		}
		//忽略全局表

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