ExecWithRollback executes or rollback.

Hashfnv32a returns 32-bit FNV-1a hash for a byte slice.

IgnoreErrors returs true if ignoreErrs contains err.

InstallArchive downloads the URL and extracts the archive to the dest diretory.

IsErrDupEntry returns true if error code = 1062.

IsErrTableNotExists checks whether err is TableNotExists error.

IsFileExist returns true if the file exists.

MustExec must execute sql or fatal.

OpenDB opens a db.

RandomlyChangeReplicaRead changes `tidb_replica_read` randomly in a session.

RandString reference: http://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-golang.

RunWithRetry tries to run func in specified count.

Wget downloads a string URL to the dest directory and returns the file path.

QueryEntry is a query.