What happens if you just use an empty range?
What I suspect is happening is that the scanner code sees a key beyond the range’s end key and stops. In general you can’t transform rows in keys for this reason, and you might have issues even if you don’t transform the rows if the keys end up out of order – see the comments in TransformingIterator. From: Yamini Joshi [mailto:[email protected]] Sent: Friday, September 30, 2016 1:37 PM To: [email protected] Subject: Re: Modify Keys within iterator I am using pyaccumulo. Here's the code snippet: rowIds=['r2','r10'] hashFilter = KeyModifyIterator(priority=10) iterator.append(hashFilter) for entry in self.dbconn.batch_scan(table , scanranges=(Range(srow=row, erow=row) for row in rowIDs),iterators=[hashFilter]): print entry Best regards, Yamini Joshi On Fri, Sep 30, 2016 at 12:31 PM, Dan Blum <[email protected]> wrote: What code are you using to test the iterator, where you see no output? From: Yamini Joshi [mailto:[email protected]] Sent: Friday, September 30, 2016 1:26 PM To: [email protected] Subject: Modify Keys within iterator Hello Everyone! I am trying to write an iterator to modify keys within a table (at scan). My use case is to select a few records that match a certain criterion and then modify them within the iterator(using the following class) for some other succeeding iterator/combiner. The problem is that this iterator does return any records/keys. I added some primitive prints and found that the keys (this.key) is changed but the output of iterator is nothing. I'd appreciate if someone could give me any insight. I'm sure I'm making a teeny tiny mistake somewhere. Schema: row colF colQ ts Val I/P: r_1 f f_1 v1 r_1 fx f_1 v1 O/P: f_1 r r_1 v1 f_1 fx fx v1 public class KeyModifyIterator implements SortedKeyValueIterator<Key,Value> { private SortedKeyValueIterator<Key,Value> source; private Key key; private Value value; @Override public void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env) throws IOException { this.source = source; } @Override public boolean hasTop() { return key != null; } @Override public void next() throws IOException { if (source.hasTop()) { ByteSequence currentRow = source.getTopKey().getRowData(); ByteSequence currentColf = source.getTopKey().getColumnFamilyData(); ByteSequence currentColq = source.getTopKey().getColumnQualifierData(); long ts = source.getTopKey().getTimestamp(); String v = source.getTopValue().toString(); System.out.println("Key = " + currentRow.toString() + " Cf = " + currentColf.toString() + " Cq = " + currentColq.toString() + " val = " + v.toString()); if (currentColf.toString().equals("fx")){ System.out.println("Updating fx" ); this.key = new Key(currentColq.toArray(), currentColf.toArray(), currentColf.toArray(), new byte[0], ts); this.value = new Value (v.getBytes(UTF_8)); } else{ System.out.println("Updating other" ); this.key = new Key(currentColq.toArray(), "r".getBytes(UTF_8), currentRow.toArray(), new byte[0], ts); this.value = new Value (v.getBytes(UTF_8)); System.out.println(this.key.toString()); } source.next(); } else { this.key = null; this.value = null; } } @Override public void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOException { source.seek(range, columnFamilies, inclusive); next(); } @Override public Key getTopKey() { return key; } @Override public Value getTopValue() { return value; } @Override public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env) { return null; } } Best regards, Yamini Joshi
