Author
Robert Wenzel, Engineer, Potix Corporation

Date
August, 2013

Version
ZK 6.5 (or later)

This page is under construction, so we cannot guarantee the accuracy of the content!

Introduction

bla bla you have some big data... how to display

based on the concepts (paging at DB level, separate paging control from grid) there how to do grouping...

The challenges

grouping is a powerful feature in ZK but also adds an extra layer of complexity

paging and grouping challenges

1. groups can be open or closed (also interactively)

-> the total count and the number of pages changes, when opening/closing nodes... (needs efficient counting, and state keeping)

2. groups can have arbitrary number of children

-> random access to a specific page ... how to know the current group and position inside the group for that page

--> implement a feaseable search

3. minimize DB operations (accumulating network/DB latency)

-> caching vs. memory consumption

1. + 2. + 3. !!!! combining all three in an efficient, memory preserving way

limitations... needs to store the state in memory (humans are limited, so one is unlikely to toggle 100+ groups)

Maxing out what is possible... ZK GroupsModel supports int indexes so go up to Integer.MAX_VALUE (~ 2.000.000.000 records)

not unrealistic -> Hibernate have changed their paging api to long already...

not use DB, just deterministic random value... caching the group sizes in memory e.g. 400.000.000 groups child counts are still 160 MB of memory