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How does PT-table checksum-Percona check replication?
pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master. The optional DSN specifies the master host.
Why are some points not configurable in InnoDB?
Because InnoDB is a complex storage engine it must be configured properly in order to perform at its best. Some points are not configurable in standard InnoDB. The goal of this feature is to provide a more exhaustive set of options for XtraDB, like ability to change the log block size.
What is the behavior of InnoDB _ log _ checksum _ algorithm?
Behavior of innodb_log_checksum_algorithm depending on its value is mostly identical to innodb_checksum_algorithm, except that the former applies to log rather than page checksums. NOTE: this feature is currently considered experimental. The following values are allowed:
How to open and flush data files in InnoDB?
O_SYNC : use O_SYNC to open and flush the log files; use fsync () to flush the data files. O_DIRECT : use O_DIRECT to open the data files and fsync () system call to flush both the data and log files.
Is there a backwards compatible version of PT-table checksum?
The table referenced in that query is the checksum table, where the checksums are stored. Each row in the table contains the checksum of one chunk of data from some table in the server. Version 2.0 of pt-table-checksum is not backwards compatible with pt-table-sync version 1.0. In some cases this is not a serious problem.
Which is faster PT table checksum or MD5?
Take into consideration that by default, pt-table-checksum use CRC32 checksums. CRC32 is not a cryptographic algorithm and for that reason it is prone to have collisions. On the other hand, CRC32 algorithm is faster and less CPU-intensive than MD5 and SHA1.