On Wed, Jan 4, 2017 at 10:44 AM, Roshan Punnoose <rosh...@gmail.com> wrote: > Keith, > > If an iterator has state that it is maintaining, what is the best way to > transfer that state to the new iterator after a tear down? For example, > MyIterator might have a Boolean flag of some sort. After tear down, is there > a way to copy that state to the new iterator before it starts seeking again?
There is nothing currently built in to help with this. What are you trying to accomplish? Are you interested in maintaining this state for a scan or batch scan? > > Roshan > > On Wed, Jan 4, 2017 at 10:33 AM Keith Turner <ke...@deenlo.com> wrote: >> >> Josh, >> >> Deepcopy is not called when an iterator is torn down. It has an >> entirely different use. Deepcopy allows cloning of an iterator during >> init(). The clones allow you to have multiple pointers into a tablets >> data which allows things like server side joins. >> >> Keith >> >> On Wed, Dec 28, 2016 at 12:50 PM, Josh Clum <joshc...@gmail.com> wrote: >> > Hi, >> > >> > I have a question about iterator teardown. It seems from >> > >> > https://github.com/apache/accumulo/blob/master/docs/src/main/asciidoc/chapters/iterator_design.txt#L383-L390 >> > that deepCopy should be called when an iterator is torn down. I'm not >> > seeing >> > that behavior. Below is a test that sets table.scan.max.memory to 1 >> > which >> > should force a tear down for each kv returned. I should see deepCopy >> > being >> > called 3 times but when I tail the Tserver logs I'm not seeing it being >> > called. Below is the test and the Tserver output. >> > >> > What am I missing here? >> > >> > Josh >> > >> > ➜ tail -f -n200 ...../accumulo/logs/TabletServer_*.out | grep >> > MyIterator >> > MyIterator: init >> > MyIterator: seek >> > MyIterator: hasTop >> > MyIterator: getTopKey >> > MyIterator: getTopValue >> > MyIterator: init >> > MyIterator: seek >> > MyIterator: hasTop >> > MyIterator: getTopKey >> > MyIterator: getTopValue >> > MyIterator: init >> > MyIterator: seek >> > MyIterator: hasTop >> > MyIterator: getTopKey >> > MyIterator: getTopValue >> > MyIterator: init >> > MyIterator: seek >> > MyIterator: hasTop >> > >> > public static class MyIterator implements SortedKeyValueIterator<Key, >> > Value> >> > { >> > >> > private SortedKeyValueIterator<Key, Value> source; >> > >> > public MyIterator() { } >> > >> > @Override >> > public void init(SortedKeyValueIterator<Key, Value> source, >> > Map<String, String> options, >> > IteratorEnvironment env) throws IOException { >> > System.out.println("MyIterator: init"); >> > this.source = source; >> > } >> > >> > @Override >> > public boolean hasTop() { >> > System.out.println("MyIterator: hasTop"); >> > return source.hasTop(); >> > } >> > >> > @Override >> > public void next() throws IOException { >> > System.out.println("MyIterator: next"); >> > source.next(); >> > } >> > >> > @Override >> > public void seek(Range range, Collection<ByteSequence> >> > columnFamilies, >> > boolean inclusive) throws IOException { >> > System.out.println("MyIterator: seek"); >> > source.seek(range, columnFamilies, inclusive); >> > } >> > >> > @Override >> > public Key getTopKey() { >> > System.out.println("MyIterator: getTopKey"); >> > return source.getTopKey(); >> > } >> > >> > @Override >> > public Value getTopValue() { >> > System.out.println("MyIterator: getTopValue"); >> > return source.getTopValue(); >> > } >> > >> > @Override >> > public SortedKeyValueIterator<Key, Value> >> > deepCopy(IteratorEnvironment >> > env) { >> > System.out.println("MyIterator: deepCopy"); >> > return source.deepCopy(env); >> > } >> > } >> > >> > @Test >> > public void testTearDown() throws Exception { >> > String table = "test"; >> > Connector conn = cluster.getConnector("root", "secret"); >> > conn.tableOperations().create(table); >> > conn.tableOperations().attachIterator(table, new IteratorSetting(25, >> > MyIterator.class)); >> > conn.tableOperations().setProperty(table, "table.scan.max.memory", >> > "1"); >> > >> > BatchWriter writer = conn.createBatchWriter(table, new >> > BatchWriterConfig()); >> > >> > Mutation m1 = new Mutation("row"); >> > m1.put("f1", "q1", 1, "val1"); >> > writer.addMutation(m1); >> > >> > Mutation m2 = new Mutation("row"); >> > m2.put("f2", "q2", 1, "val2"); >> > writer.addMutation(m2); >> > >> > Mutation m3 = new Mutation("row"); >> > m3.put("f3", "q3", 1, "val3"); >> > writer.addMutation(m3); >> > >> > writer.flush(); >> > writer.close(); >> > >> > BatchScanner scanner = conn.createBatchScanner(table, new >> > Authorizations(), 3); >> > scanner.setRanges(Collections.singletonList(new Range())); >> > for(Map.Entry<Key, Value> entry : scanner) { >> > System.out.println(entry.getKey() + " : " + entry.getValue()); >> > } >> > System.out.println("Results complete!"); >> > }
