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https://issues.apache.org/jira/browse/OAK-1263?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13919193#comment-13919193
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Thomas Mueller commented on OAK-1263:
-------------------------------------
Please note my comments are all about formatting, naming conventions, and so
on. The patch itself looks good!
But still, some more comments:
{noformat}
import static org.apache.jackrabbit.oak.plugins.index.property.OrderedIndex.*;
{noformat}
I personally don't like static imports (but this is a matter of taste), but I
think we agreed we don't use star imports.
OrderedPropertyIndexEditor and OrderedPropertyIndexEditorProvider: the license
header is missing.
OrderedPropertyIndexEditorProvider, variable "_editor": we don't use the
underline prefix (for anything). Just rename it to "editor". The same for other
variables, for example "NodeBuilder _key".
{noformat}
/* (non-Javadoc)
* @see
org.apache.jackrabbit.oak.spi.query.QueryIndexProvider#getQueryIndexes(org.apache.jackrabbit.oak.spi.state.NodeState)
*/
{noformat}
I don't see a value in that comment. Could you remove it please?
Could you add class level javadoc comments (for example for for
OrderedContentMirrorStoreStrategy)?
{noformat}
public static final String NEXT = ":next";
{noformat}
This is the wrong order, could you use:
{noformat}
public final static String NEXT = ":next";
{noformat}
{noformat}
public void firstAndOnlyItem() {
final String PATH = "/foo/bar";
{noformat}
The naming convention for variables is to use lowercase. Could you rename the
variable to "path" please?
{noformat}
assertEquals("Expecting 2 items in the index", 2,
Iterators.size(children.iterator())); // how
// many
// entries
// do
// we
// have?
{noformat}
Could you remove, or move the line comment to _before_ the line please? For
example:
{noformat}
// how many entries do we have?
assertEquals("Expecting 2 items in the index", 2,
Iterators.size(children.iterator()));
{noformat}
> optimize oak index to support 'fast ORDER BY' queries to support sorting &
> pagination for large set of children
> ---------------------------------------------------------------------------------------------------------------
>
> Key: OAK-1263
> URL: https://issues.apache.org/jira/browse/OAK-1263
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: query
> Affects Versions: 0.12
> Reporter: Stefan Egli
> Assignee: Alex Parvulescu
> Fix For: 0.18
>
> Attachments: OAK-1263-r1.patch, OAK-1263-r1a.patch,
> benchmark-20140228112150.log, benchmark-20140228120718.log,
> benchmark-20140228125248.log
>
>
> We have a use case where we'd like to be able to use an index in a
> "pagination-like" fashion. That is, we'd like to be able to have an index on
> a subtree on a certain property, and then run a query which does ORDER BY
> that property combined with OFFSET. That way, essentially allowing pagination
> of child nodes of a particular parent based on 'sorted by a certain property'.
> AFAIU currently the oak index is not optimized to support ORDER BY queries in
> a fast manner. The index keeps 'the child nodes unsorted', ie to process an
> ORDER BY, the child nodes would have to be 'manually sorted' which can result
> in bad performance given a large number of child nodes.
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