Scan a table; pass table name and optionally a dictionary of scanner
specifications. Scanner specifications may include one or more of:
TIMERANGE, FILTER, LIMIT, STARTROW, STOPROW, TIMESTAMP, MAXLENGTH,
or COLUMNS, CACHEIf no columns are specified, all columns will be scanned.
To scan all members of a column family, leave the qualifier empty as in
‘col_family:’.The filter can be specified in two ways:
1. Using a filterString – more information on this is available in the
Filter Language document attached to the HBASE-4176 JIRA
2. Using the entire package name of the filter.Some examples:hbase> scan ‘.META.’
hbase> scan ‘.META.’, {COLUMNS => ‘info:regioninfo’}
hbase> scan ‘t1′, {COLUMNS => [‘c1′, ‘c2′], LIMIT => 10, STARTROW => ‘xyz’}
hbase> scan ‘t1′, {COLUMNS => ‘c1′, TIMERANGE => [1303668804, 1303668904]}
hbase> scan ‘t1′, {FILTER => “(PrefixFilter (‘row2′) AND
(QualifierFilter (>=, ‘binary:xyz’))) AND (TimestampsFilter ( 123, 456))”}
hbase> scan ‘t1′, {FILTER =>
org.apache.hadoop.hbase.filter.ColumnPaginationFilter.new(1

, 0)}

For experts, there is an additional option — CACHE_BLOCKS — which
switches block caching for the scanner on (true) or off (false). By
default it is enabled. Examples:hbase> scan ‘t1′, {COLUMNS => [‘c1′, ‘c2′], CACHE_BLOCKS => false}

Also for experts, there is an advanced option — RAW — which instructs the
scanner to return all cells (including delete markers and uncollected deleted
cells). This option cannot be combined with requesting specific COLUMNS.
Disabled by default. Example:

hbase> scan ‘t1′, {RAW => true, VERSIONS => 10}

Besides the default ‘toStringBinary’ format, ‘scan’ supports custom formatting
by column. A user can define a FORMATTER by adding it to the column name in
the scan specification. The FORMATTER can be stipulated:

1. either as a org.apache.hadoop.hbase.util.Bytes method name (e.g, toInt, toString)
2. or as a custom class followed by method name: e.g. ‘c(MyFormatterClass).format’.

Example formatting cf:qualifier1 and cf:qualifier2 both as Integers:
hbase> scan ‘t1′, {COLUMNS => [‘cf:qualifier1:toInt’,
‘cf:qualifier2:c(org.apache.hadoop.hbase.util.Bytes).toInt’] }

Note that you can specify a FORMATTER by column only (cf:qualifer). You cannot
specify a FORMATTER for all columns of a column family.

Scan can also be used directly from a table, by first getting a reference to a
table, like such:

hbase> t = get_table ‘t’
hbase> t.scan

Note in the above situation, you can still provide all the filtering, columns,
options, etc as described above.