HBASE-21636 Enhance the shell scan command to support missing scanner specifications like ReadType, IsolationLevel etc.

hbase-shell/src/main/ruby/hbase/table.rb

@@ -508,6 +508,13 @@ EOF
         # Normalize column names
         columns = [columns] if columns.class == String
         limit = args['LIMIT'] || -1
+        replica_id = args[REGION_REPLICA_ID]
+        isolation_level = args[ISOLATION_LEVEL]
+        read_type = args[READ_TYPE]
+        allow_partial_results = args[ALLOW_PARTIAL_RESULTS].nil? ? false : args[ALLOW_PARTIAL_RESULTS]
+        batch = args[BATCH] || -1
+        max_result_size = args[MAX_RESULT_SIZE] || -1
+
         unless columns.is_a?(Array)
           raise ArgumentError, 'COLUMNS must be specified as a String or an Array'
         end
@@ -549,10 +556,16 @@ EOF
         scan.setMaxVersions(versions) if versions > 1
         scan.setTimeRange(timerange[0], timerange[1]) if timerange
         scan.setRaw(raw)
-        scan.setCaching(limit) if limit > 0
+        scan.setLimit(limit) if limit > 0
         set_attributes(scan, attributes) if attributes
         set_authorizations(scan, authorizations) if authorizations
         scan.setConsistency(org.apache.hadoop.hbase.client.Consistency.valueOf(consistency)) if consistency
+        scan.setReplicaId(replica_id) if replica_id
+        scan.setIsolationLevel(org.apache.hadoop.hbase.client.IsolationLevel.valueOf(isolation_level)) if isolation_level
+        scan.setReadType(org.apache.hadoop.hbase.client::Scan::ReadType.valueOf(read_type)) if read_type
+        scan.setAllowPartialResults(allow_partial_results) if allow_partial_results
+        scan.setBatch(batch) if batch > 0
+        scan.setMaxResultSize(max_result_size) if max_result_size > 0
       else
         scan = org.apache.hadoop.hbase.client.Scan.new
       end
@@ -571,7 +584,6 @@ EOF
       raise(ArgumentError, 'Scan argument should be org.apache.hadoop.hbase.client.Scan') \
         unless scan.nil? || scan.is_a?(org.apache.hadoop.hbase.client.Scan)
 
-      limit = args['LIMIT'] || -1
       maxlength = args.delete('MAXLENGTH') || -1
       converter = args.delete(FORMATTER) || nil
       converter_class = args.delete(FORMATTER_CLASS) || 'org.apache.hadoop.hbase.util.Bytes'
@@ -605,13 +617,8 @@ EOF
             res[key][column] = cell
           end
         end
-
         # One more row processed
         count += 1
-        if limit > 0 && count >= limit
-          # If we reached the limit, exit before the next call to hasNext
-          break
-        end
       end
 
       scanner.close

hbase-shell/src/main/ruby/hbase_constants.rb

@@ -65,6 +65,11 @@ module HBaseConstants
   NUMREGIONS = 'NUMREGIONS'.freeze
   REGION_REPLICATION = 'REGION_REPLICATION'.freeze
   REGION_REPLICA_ID = 'REGION_REPLICA_ID'.freeze
+  ISOLATION_LEVEL = 'ISOLATION_LEVEL'.freeze
+  READ_TYPE = 'READ_TYPE'.freeze
+  ALLOW_PARTIAL_RESULTS = 'ALLOW_PARTIAL_RESULTS'.freeze
+  BATCH = 'BATCH'.freeze
+  MAX_RESULT_SIZE = 'MAX_RESULT_SIZE'.freeze
   CONFIGURATION = org.apache.hadoop.hbase.HConstants::CONFIGURATION
   ATTRIBUTES = 'ATTRIBUTES'.freeze
   VISIBILITY = 'VISIBILITY'.freeze

hbase-shell/src/main/ruby/shell/commands/scan.rb

@@ -25,7 +25,9 @@ module Shell
 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, ROWPREFIXFILTER, TIMESTAMP,
-MAXLENGTH or COLUMNS, CACHE or RAW, VERSIONS, ALL_METRICS or METRICS
+MAXLENGTH, COLUMNS, CACHE, RAW, VERSIONS, ALL_METRICS, METRICS,
+REGION_REPLICA_ID, ISOLATION_LEVEL, READ_TYPE, ALLOW_PARTIAL_RESULTS,
+BATCH or MAX_RESULT_SIZE
 
 If no columns are specified, all columns will be scanned.
 To scan all members of a column family, leave the qualifier empty as in
@@ -56,6 +58,8 @@ Some examples:
   hbase> scan 't1', {FILTER =>
     org.apache.hadoop.hbase.filter.ColumnPaginationFilter.new(1, 0)}
   hbase> scan 't1', {CONSISTENCY => 'TIMELINE'}
+  hbase> scan 't1', {ISOLATION_LEVEL => 'READ_UNCOMMITTED'}
+  hbase> scan 't1', {MAX_RESULT_SIZE => 123456}
 For setting the Operation Attributes
   hbase> scan 't1', { COLUMNS => ['c1', 'c2'], ATTRIBUTES => {'mykey' => 'myvalue'}}
   hbase> scan 't1', { COLUMNS => ['c1', 'c2'], AUTHORIZATIONS => ['PRIVATE','SECRET']}
@@ -72,6 +76,11 @@ Disabled by default.  Example:
 
   hbase> scan 't1', {RAW => true, VERSIONS => 10}
 
+There is yet another option -- READ_TYPE -- which instructs the scanner to
+use a specific read type. Example:
+
+  hbase> scan 't1', {READ_TYPE => 'PREAD'}
+
 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:

hbase-shell/src/test/ruby/hbase/table_test.rb

@@ -602,6 +602,30 @@ module Hbase
       assert_nil(res['2']['x:b'])
     end
 
+    define_test 'scan should support REGION_REPLICA_ID' do
+      res = @test_table._scan_internal REGION_REPLICA_ID => 0
+      assert_not_nil(res)
+    end
+
+    define_test 'scan should support ISOLATION_LEVEL' do
+      res = @test_table._scan_internal ISOLATION_LEVEL => 'READ_COMMITTED'
+      assert_not_nil(res)
+    end
+
+    define_test 'scan should support READ_TYPE parameter' do
+      res = @test_table._scan_internal READ_TYPE => 'PREAD'
+      assert_not_nil(res)
+      res = @test_table._scan_internal READ_TYPE => 'STREAM'
+      assert_not_nil(res)
+      res = @test_table._scan_internal READ_TYPE => 'DEFAULT'
+      assert_not_nil(res)
+    end
+
+    define_test 'scan should support ALLOW_PARTIAL_RESULTS' do
+      res = @test_table._scan_internal ALLOW_PARTIAL_RESULTS => true
+      assert_not_nil(res)
+    end
+
     define_test "scan should work with raw and version parameter" do
       # Create test table if it does not exist
       @test_name_raw = "hbase_shell_tests_raw_scan"