Help Center/ Data Replication Service/ User Guide (Paris Region) / FAQs/ Data-Level Comparison/ What Impact Does a DRS Comparison Task Have on Databases?
Updated on 2023-01-05 GMT+08:00
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What Impact Does a DRS Comparison Task Have on Databases?

  • Object comparison: System tables of the source and destination databases are queried, occupying about 10 sessions. The database is not affected. However, if there are a large number of objects (for example, hundreds of thousands of tables), the database may be overloaded.
  • Row comparison: The number of rows in the source and destination databases is queried, which occupies about 10 sessions. The SELECT COUNT statement does not affect the database. However, if a table contains a large amount of data (hundreds of millions of records), the database will be overloaded and the query results will be returned slowly.
  • Value comparison: All data in the source and destination databases is queried, and each field is compared. The query pressure on the database leads to high I/O. The query speed is limited by the I/O and network bandwidth of the source and destination databases. Value comparison occupies one or two CPUs, and about 10 sessions.
Parent topic: Data-Level Comparison