This topic provides answers to some frequently asked questions about ApsaraDB RDS.

Basic concepts

  • What is a database instance?

    A database instance is a database server on which you can create one or more databases. Each database can contain one or more tables.

  • What are primary RDS instances and secondary RDS instances?

    If you are using the RDS High-availability Edition, Cluster Edition, or Enterprise Edition, your application connects to the primary RDS instance of your database system. In addition, the primary RDS instance synchronizes data to the secondary RDS instance in real time.

    You can access only the primary RDS instance. The secondary RDS instance serves as a standby and cannot be connected to your application. If the primary RDS instance becomes abnormal, your database system fails over to the secondary RDS instance. In this case, the roles of the primary and secondary RDS instances are switched. During the failover, your database service remains available. However, a transient connection may occur.

    For more information about the primary and secondary RDS instances in each RDS edition, see Overview of ApsaraDB RDS editions.

  • What are read-only RDS instances?

    Read-only RDS instances are provided to scale the read capability of your database system. If your database system receives a small number of write requests but a large number of read requests, the primary RDS instance may not be able to process these read requests and your workloads may be interrupted. In this case, you can create one or more read-only RDS instances to offload read requests from the primary RDS instance. Read-only RDS instances help ensure the stability of your database system and increase the throughput of your application.

    For more information, see Overview of read-only ApsaraDB RDS for MySQL instances.

Billing and purchase

  • Why am I charged additional fees for a subscription RDS instance?

    When you purchase a subscription RDS instance, you are charged only for the instance and the storage capacity. If you create read-only RDS instances, enable the SQL Explorer feature, configure the monitoring frequency, or use more storage than what is allowed by the free quota for backup storage, you are charged additional fees. For more information, see Pricing, billable items, and billing methods.

  • After I submit an order to purchase an RDS instance, why is the ApsaraDB RDS console not responding and why am I unable to find the RDS instance that I created?

    The preceding issue may occur due to the following reasons:

    • The RDS instance does not reside in the region that you selected.

      In the top navigation bar, select the region where the RDS instance resides. Then, you can find the RDS instance that you created.

      Select a region
    • The selected zone cannot provide the required number of resources.

      Resources in zones are dynamically allocated. After you submit a purchase order, the zone that you selected may be unable to provide sufficient resources. As a result, the RDS instance cannot be created. We recommend that you select a different zone and try again. If the RDS instance still cannot be created, you can go to the Orders page in the Billing Management console to view the refunded fee.

  • Am I charged for a pay-as-you-go RDS instance that I am not using?

    Yes, you are charged an hourly fee for every pay-as-you-go RDS instance that you create even if you are not using these RDS instances. A pay-as-you-go RDS instance consumes computing and storage resources even if it is not used. If you do not intend to use a pay-as-you-go RDS instance for a long period of time, we recommend that you save the required data and release the RDS instance.

  • Can I switch between the subscription and pay-as-you-go billing methods?

    Yes, you can switch between the subscription and pay-as-you-go billing methods. For more information, see Switch an ApsaraDB RDS for MySQL instance from pay-as-you-go to subscription and Switch an ApsaraDB RDS for MySQL instance from subscription to pay-as-you-go.

  • How much do I need to pay if I change the specifications of my subscription RDS instance?

    For more information, see Specification change fees.

  • What happens if my subscription RDS instance expires or the payment is overdue?

    For more information, see Unlock or rebuild an expired or overdue ApsaraDB RDS instance.

  • Is the inbound and outbound Internet traffic that is consumed for my pay-as-you-go and subscription RDS instances free of charge?

    Yes, all inbound and outbound Internet traffic that is consumed for your pay-as-you-go and subscription RDS instances are free of charge.

  • Do I need to pay when I apply for a public endpoint?

    No, you are not charged when you apply for a public endpoint.

  • When an entry-level RDS instance and an enterprise-level RDS instance have the same vCPU and memory specifications, why does the entry-level RDS instance support a larger number of connections and deliver higher IOPS than the enterprise-level RDS instance?

    An entry-level RDS instance belongs to the shared or general-purpose instance family, whereas an enterprise-level RDS instance belongs to the dedicated instance family. The shared and general-purpose instance families support the reuse of vCPU resources. Therefore an entry-level RDS instance supports a larger maximum number of connections and delivers higher IOPS than an enterprise-level RDS instance. However, enterprise-level RDS instances provide a more reliable database service because the dedicated instance family supports the exclusive allocations of vCPU and memory resources. For more information, see Overview.

Instance management

  • How do I authorize a RAM user to manage my RDS instance?

    For more information, see Use RAM to manage ApsaraDB RDS permissions.

  • How do I change the VPC of my RDS instance?
    • If your RDS instance supports virtual private cloud (VPC) and vSwitch changes, you can directly change the VPC of your instance. For more information, see Switch an ApsaraDB RDS for MySQL instance to a new VPC and a new vSwitch.
    • If your RDS instance supports changes between the classic and VPC network types, perform the following steps:
      1. Change the network type from VPC to classic network.
      2. Change the network type from classic network to VPC. You can select the VPC based on your business requirements.
    • If your RDS instance does not support changes between the classic and VPC network types, perform the following steps:

      Purchase an RDS instance that resides in the required VPC. Then, migrate the data of your RDS instance to the new RDS instance. For more information, see Migrate data between ApsaraDB RDS instances.

  • Can I access the secondary RDS instance of my database system?

    No, you cannot access the secondary RDS instance of your database system. You can access only the primary RDS instance. The secondary RDS instance serves only as a standby and does not support external access.

  • If my RDS instance resides in a VPC, how many private IP addresses does my RDS instance have?
    The number of private IP addresses that your RDS instance has varies based on the database engine and RDS edition that are used.
    • MySQL 5.5, 5.6, 5.7, and 8.0 on RDS High-availability Edition with local SSDs: 1
    • MySQL 5.6, 5.7, and 8.0 on RDS Enterprise Edition with local SSDs: 1
    • MySQL 5.7 on RDS Basic Edition with standard SSDs: 1
    • MySQL 8.0 on RDS Basic Edition with standard SSDs: 2
    • MySQL 5.7 and 8.0 on RDS High-availability Edition with standard SSDs or enhanced SSDs (ESSDs): 3
    • MySQL 5.7 and 8.0 on RDS Enterprise Edition with standard SSDs or ESSDs: 1

Change specifications

  • What do I do if an RDS instance is locked due to insufficient storage?

    You can submit a ticket to contact Alibaba Cloud technical support.

  • What do I do if the disk storage of my RDS instance is exhausted?
  • After I upgrade my primary RDS instance, does ApsaraDB RDS automatically upgrade the read-only RDS instances?

    No, after you upgrade your primary RDS instance, you must manually upgrade the read-only RDS instances.

  • How do I change the storage type of my RDS instance among local SSD, standard SSD, and ESSD?

    For more information, see How do I migrate an ApsaraDB RDS instance from standard or enhanced SSDs to local SSDs?.

  • How much time is required to expand the storage capacity of my RDS instance?

    The required time varies based on whether the physical host on which your RDS instance resides can provide the required amount of remaining storage capacity for your expansion plan. If the remaining storage capacity is sufficient, you do not need to migrate the data of your RDS instance. In this case, the required time is short. If the remaining storage capacity is insufficient, you must migrate the data of your RDS instance to another qualified physical host before you start the expansion. This process is complicated and time-consuming.

  • When I change the specifications of my RDS instance, are my online workloads interrupted?

    No, your online workloads are not interrupted when you change the specifications of your RDS instance. However, a transient connection of about 30 seconds occurs during the subsequent switchover.

  • After I change the specifications of my RDS instance, do the endpoints of the RDS instance change?

    After you change the specifications of your RDS instance, the internal, public, and read/write splitting endpoints of the RDS instance remain unchanged. However, the IP addresses that are associated with the endpoints may change. For more information, see View and change the internal and public endpoints and port numbers of an ApsaraDB RDS for MySQL instance and Enable the read/write splitting feature in the shared proxy of an ApsaraDB RDS for MySQL instance. We recommend that you use the internal, public, or read/write splitting endpoint of your RDS instance to establish a connection from your application.

  • When I expand the storage capacity of my RDS instance, an error that indicates insufficient storage resources is reported. What do I do?

    Migrate your RDS instance to another zone. Then, expand the storage capacity of your RDS instance. For more information, see Migrate an ApsaraDB RDS for MySQL instance across zones in the same region. After you migrate your RDS instance to another zone, the endpoints of your RDS instance remain unchanged. However, the IP addresses that are associated with the endpoints change. Make sure that your application is configured to automatically reconnect to your RDS instance.

Security

  • After I configure an IP address whitelist, does the IP address whitelist immediately take effect?

    No, after you configure an IP address whitelist, the IP address whitelist requires about 1 minute to take effect.

  • Why do I find IP address whitelists that I did not create?
    If these IP address whitelists contain private IP addresses, these IP address whitelists may be created by other Alibaba Cloud services, such as Data Management (DMS) and Database Autonomy Service (DAS). These IP address whitelists do not put your data at risk. IP address whitelist generated by HDM
  • If I disable Internet access and enable only internal network access, is my RDS instance exposed to security risks?

    Yes, your RDS instance is exposed to security risks. We recommend that you change the network type of your RDS instance to VPC. In this case, only an ECS instance that resides in the same VPC can access your RDS instance after the required IP address is added to an IP address whitelist of your RDS instance. For more information, see Change the network type of an ApsaraDB RDS for MySQL instance.

  • If I do not update an expired SSL certificate, does my RDS instance malfunction or data security deteriorate?

    If you do not update an expired SSL certificate, your RDS instance still runs as excepted and no security risks occur. However, if your application uses encrypted connections to communicate with your RDS instance, your application is disconnected.

Audit

How do I obtain the size of the SQL log data that is generated by the SQL Explorer feature?

Log on to the ApsaraDB RDS console, find your RDS instance, and then go to the Basic Information page. In the Usage Statistics section of the page, you can view the size of the SQL log data that is generated by the SQL Explorer feature. Log Size

Connection

Database and account management

  • Can I manage accounts on my RDS instance at more fine-grained levels, such as the source IP address and table levels?

    Yes, you can log on to your RDS instance and use commands to grant permissions to accounts at more fine-grained levels. For more information, see Connect to an ApsaraDB RDS for MySQL instance.

  • Which specific permissions do privileged accounts and standard accounts have?

    For more information, see Create accounts and databases for an ApsaraDB RDS for MySQL instance.

  • Does ApsaraDB RDS provide accounts that are equivalent to root accounts or superuser accounts?

    No, ApsaraDB RDS does not provide accounts that are equivalent to root accounts or superuser accounts. This way, you can protect your RDS instance from data loss and leaks that are caused by unintentional operations.

  • After I create accounts on my primary RDS instance, can I manage the accounts on the read-only RDS instances?

    No, although the accounts created on your primary RDS instance are synchronized to the read-only RDS instances, you cannot manage the accounts from the read-only RDS instances. The accounts can only read data from RDS instances.

Read-only RDS instance and read/write splitting

  • After I upgrade my primary RDS instance, does ApsaraDB RDS automatically upgrade the read-only RDS instances?

    No, after you upgrade your primary RDS instance, you must manually upgrade the read-only RDS instances. For more information, see Change the specifications of an ApsaraDB RDS for MySQL instance.

  • After I set the read weight of a read-only RDS instance to 0, can I still connect to the read-only RDS instance?

    Yes, after you set the read weight of a read-only RDS instance to 0, you can still connect to the read-only RDS instance by using the internal or public endpoint. However, you cannot connect to the read-only RDS instance by using the read/write splitting endpoint. For more information, see View and change the internal and public endpoints and port numbers of an ApsaraDB RDS for MySQL instance. This feature is used to configure a read-only RDS instance to process only specific workloads.

  • If I release a read-only RDS instance, are my workloads be interrupted?

    Yes, if you release a read-only RDS instance, your workloads are interrupted. Before you release a read-only RDS instance, we recommend that you set the read weight of the read-only RDS instance to 0. For more information, see Modify the latency threshold and read weights of ApsaraDB RDS for MySQL instances. However, the cached connection with your database system remains valid on the read-only RDS instance that you released. You must close the connection and establish a new connection.

  • What do I do if read/write splitting becomes abnormal?

    For more information, see FAQ on read/write splitting.

  • If my primary RDS instance processes a small number of write requests, can read requests also be sent to my primary RDS instance?

    Yes, the read requests can also be sent to your primary RDS instance. You can specify the read weight of the primary RDS instance. For more information, see Read/write splitting.

Backup and restoration

  • Can I disable the data backup feature of my ApsaraDB RDS for MySQL instance?

    No, you cannot disable the data backup feature of your ApsaraDB RDS for MySQL instance. However, you can reduce the data backup frequency to at least twice a week. The data backup retention period must span at least seven days.

  • Can I disable the log backup feature of my ApsaraDB RDS for MySQL instance?

    Yes, if your ApsaraDB RDS for MySQL instance does not run the RDS Basic Edition, you can disable the log backup feature in the ApsaraDB RDS console.

  • Why did my backup task fail?

    DDL statements trigger locks on tables. If you execute DDL statements during a backup, the backup may fail due to table locks.

  • Why do I find two log backup files with the same name on the Log Backup tab?
    If you are using the RDS High-availability Edition, your database system consists of a primary RDS instance and a secondary RDS instance. Both instances generate log backup files. Each log backup file is identified by an Instance ID on the Log Backup tab. You can use the instance IDs to distinguish the log backup files that are generated by the primary RDS instance from the log backup files that are generated by the secondary RDS instance. On the Service Availability page, you can view the IDs of the primary and secondary RDS instances based on the Primary Instance No. and Secondary Instance No. fields. Service Availability page in the original ApsaraDB RDS console
  • What do I do with the data backup files and log backup files that I downloaded?

    You can use the data backup files and log backup files that you downloaded to restore data at any time. For more information, see Restore the data of an ApsaraDB RDS for MySQL instance from a physical backup file to a self-managed MySQL database and Restore the data of an ApsaraDB RDS for MySQL instance from a logical backup file to a self-managed MySQL instance.

  • Why is the size of the snapshot that is generated for my RDS instance large even if the amount of data on the instance is small? When ApsaraDB RDS takes a snapshot of your RDS instance, ApsaraDB RDS eliminates empty blocks. This way, the size of the snapshot is smaller than the required disk space. The size of each block is 2 MB. However, if write operations are dispersed, a large number of blocks are not full. For example, 3 MB of data may be written into two, three, or four blocks. In this case, none of these blocks are full. When ApsaraDB RDS calculates the size of the snapshot, ApsaraDB RDS counts all non-empty blocks to which data is written. As a result, the disk space that is occupied by the snapshot is larger than the actual size of the snapshot.
  • How do I query data from backup files?

    If you have full logical backup files, you can use Database Backup (DBS) to query data from these files. This way, you do not need to restore the data of these files. For more information, see Backup set query overview.