HdfsFindTool is essentially the HDFS version of the Linux filesystem find command. The command walks one or more HDFS directory trees, finds all HDFS files that match the specified expression, and applies selected actions to them. By default, it prints the list of matching HDFS file paths to stdout, one path per line. The output file list can be piped into the MapReduceIndexerTool using the MapReduceIndexerTool --inputlist option.
More details are available through command-line help. The command used to invoke the help varies by installation type and may vary further in custom installations.
- To invoke the command-line help in a default parcels installation, use:
$ hadoop jar /opt/cloudera/parcels/CDH-*/jars/search-mr-*-job.jar \ org.apache.solr.hadoop.HdfsFindTool -help
- To invoke the command-line help in a default packages installation, use:
$ hadoop jar /usr/lib/solr/contrib/mr/search-mr-job.jar \ org.apache.solr.hadoop.HdfsFindTool -help
More details are available through the command line help:
Usage: hadoop fs [generic options] [-find <path> ... <expression> ...] [-help [cmd ...]] [-usage [cmd ...]] -find <path> ... <expression> ...: Finds all files that match the specified expression and applies selected actions to them. The following primary expressions are recognised: -atime n -amin n Evaluates as true if the file access time subtracted from the start time is n days (or minutes if -amin is used). -blocks n Evaluates to true if the number of file blocks is n. -class classname [args ...] Executes the named expression class. -depth Always evaluates to true. Causes directory contents to be evaluated before the directory itself. -empty Evaluates as true if the file is empty or directory has no contents. -group groupname Evaluates as true if the file belongs to the specified group. -mtime n -mmin n Evaluates as true if the file modification time subtracted from the start time is n days (or minutes if -mmin is used) -name pattern -iname pattern Evaluates as true if the basename of the file matches the pattern using standard file system globbing. If -iname is used then the match is case insensitive. -newer file Evaluates as true if the modification time of the current file is more recent than the modification time of the specified file. -nogroup Evaluates as true if the file does not have a valid group. -nouser Evaluates as true if the file does not have a valid owner. -perm [-]mode -perm [-]onum Evaluates as true if the file permissions match that specified. If the hyphen is specified then the expression shall evaluate as true if at least the bits specified match, otherwise an exact match is required. The mode may be specified using either symbolic notation, eg 'u=rwx,g+x+w' or as an octal number. -print -print0 Always evaluates to true. Causes the current pathname to be written to standard output. If the -print0 expression is used then an ASCII NULL character is appended. -prune Always evaluates to true. Causes the find command to not descend any further down this directory tree. Does not have any affect if the -depth expression is specified. -replicas n Evaluates to true if the number of file replicas is n. -size n[c] Evaluates to true if the file size in 512 byte blocks is n. If n is followed by the character 'c' then the size is in bytes. -type filetype Evaluates to true if the file type matches that specified. The following file type values are supported: 'd' (directory), 'l' (symbolic link), 'f' (regular file). -user username Evaluates as true if the owner of the file matches the specified user. The following operators are recognised: expression -a expression expression -and expression expression expression Logical AND operator for joining two expressions. Returns true if both child expressions return true. Implied by the juxtaposition of two expressions and so does not need to be explicitly specified. The second expression will not be applied if the first fails. ! expression -not expression Evaluates as true if the expression evaluates as false and vice-versa. expression -o expression expression -or expression Logical OR operator for joining two expressions. Returns true if one of the child expressions returns true. The second expression will not be applied if the first returns true. -help [cmd ...]: Displays help for given command or all commands if none is specified. -usage [cmd ...]: Displays the usage for given command or all commands if none is specified. Generic options supported are -conf <configuration file> specify an application configuration file -D <property=value> use value for given property -fs <local|namenode:port> specify a namenode -jt <local|jobtracker:port> specify a job tracker -files <comma separated list of files> specify comma separated files to be copied to the map reduce cluster -libjars <comma separated list of jars> specify comma separated jar files to include in the classpath. -archives <comma separated list of archives> specify comma separated archives to be unarchived on the compute machines. The general command line syntax is bin/hadoop command [genericOptions] [commandOptions]
For example, to find all files that:
- Are contained in the directory tree hdfs:///user/$USER/solrloadtest/twitter/tweets
- Have a name matching the glob pattern sample-statuses*.gz
- Were modified less than 60 minutes ago
- Are between 1 MB and 1 GB
You could use the following:
$ hadoop jar /usr/lib/solr/contrib/mr/search-mr-*-job.jar \ org.apache.solr.hadoop.HdfsFindTool -find \ hdfs:///user/$USER/solrloadtest/twitter/tweets -type f -name \ 'sample-statuses*.gz' -mmin -60 -size -1000000000c -size +1000000c