CRC32C
MariaDB starting with 10.8
Introduced in MariaDB 10.8.0 to compute a cyclic redundancy check (CRC) value using the Castagnoli polynomial.
Syntax
CRC32C([par,]expr)
Description
MariaDB has always included a native unary function CRC32() that computes the CRC-32 of a string using the ISO 3309 polynomial that used by zlib and many others.
InnoDB and MyRocks use a different polynomial, which was implemented in SSE4.2 instructions that were introduced in the Intel Nehalem microarchitecture. This is commonly called CRC-32C (Castagnoli).
The CRC32C function uses the Castagnoli polynomial.
This allows SELECT…INTO DUMPFILE to be used for the creation of files with
valid checksums, such as a logically empty InnoDB redo log file
ib_logfile0 corresponding to a particular log sequence number.
The optional parameter allows the checksum to be computed in pieces: CRC32C('MariaDB')=CRC32C(CRC32C('Maria'),'DB').
Examples
SELECT CRC32C('MariaDB'); +-------------------+ | CRC32C('MariaDB') | +-------------------+ | 809606978 | +-------------------+ SELECT CRC32C(CRC32C('Maria'),'DB'); +------------------------------+ | CRC32C(CRC32C('Maria'),'DB') | +------------------------------+ | 809606978 | +------------------------------+
