alibaba/canal · error · NullPointerException

dbMapping.database

Error message

dbMapping.database

What it means

Thrown by rdb MappingConfig.validate() when dbMapping.database is null or empty. Validation runs during config load at adapter startup. database is the source schema name used to route events and is required even for mirrorDb mode.

Source

Thrown at client-adapter/rdb/src/main/java/com/alibaba/otter/canal/client/adapter/rdb/config/MappingConfig.java:84

    public void setDbMapping(DbMapping dbMapping) {
        this.dbMapping = dbMapping;
    }

    public String getDestination() {
        return destination;
    }

    public void setDestination(String destination) {
        this.destination = destination;
    }

    public AdapterMapping getMapping() {
        return dbMapping;
    }

    public void validate() {
        if (dbMapping.database == null || dbMapping.database.isEmpty()) {
            throw new NullPointerException("dbMapping.database");
        }
        if (!dbMapping.getMirrorDb() && (dbMapping.table == null || dbMapping.table.isEmpty())) {
            throw new NullPointerException("dbMapping.table");
        }
        if (!dbMapping.getMirrorDb() && (dbMapping.targetTable == null || dbMapping.targetTable.isEmpty())) {
            throw new NullPointerException("dbMapping.targetTable");
        }
    }

    public static class DbMapping implements AdapterMapping {

        private boolean             mirrorDb        = false;                 // 是否镜像库
        private String              database;                                // 数据库名或schema名
        private String              table;                                   // 表名
        private Map<String, String> targetPk        = new LinkedHashMap<>(); // 目标表主键字段
        private boolean             mapAll          = false;                 // 映射所有字段
        private String              targetDb;                                // 目标库名
        private String              targetTable;                             // 目标表名

View on GitHub (pinned to 87be50e876)

Solutions

1. Add a non-empty 'database:' under dbMapping in the failing rdb yml.
2. Fix indentation so 'database' is a child of dbMapping.

Example fix

# before
dbMapping:
  table: user
# after
dbMapping:
  database: mytest
  table: user

DbMapping m = config.getDbMapping();
if (m == null || m.getDatabase() == null || m.getDatabase().isEmpty()) {
    throw new IllegalArgumentException("rdb yml missing dbMapping.database for " + fileName);
}

When it happens

Trigger: An rdb mapping yml parses but its dbMapping block omits or blanks 'database:'.

Common situations: A copied template had 'database:' removed, or indentation places 'database' outside the dbMapping block.

Related errors

• dbMapping.table
• dbMapping.targetTable
• KuduMapping.database
• dbMapping.database
• dbMapping.table

AI-assisted analysis of alibaba/canal@87be50e876 (2026-08-14). Data as JSON: /api/errors/b7034218d8b5b9f6. Report an issue: GitHub.