Optimize Groovy code - groovy

Question

I am fairly new to the Groovy/Grails arena. I recently modified some code to add the following block.
result.processed.each{
def queueEntry = QueueEntry.findById(it.id)<<<START ADD>>>
Set dates = new HashSet<Long>()
def children = QueueEntry.findAllByParent(queueEntry)
for(QueueEntry qe : children){
def f = new GregorianCalendar()
f.setTimeInMillis(DateUtils.getClearedTime(qe.entryTimestamp))
def l = new GregorianCalendar()
l.setTimeInMillis(DateUtils.getClearedTime(qe.exitTimestamp))
while(f < l){
if(f.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY && f.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY){//only add weekdays
dates.add(f.time.time)
}
def xx = new GregorianCalendar()
xx.setTimeInMillis(f.time.next().time)
f = xx
}
dates.add(l.time.time)
} <<<STOP ADD>>>
Set outsideDays = it.numberOfDaysOutsideCVB
Set days = DateUtils.businessDaysBetweenDates(it.entryTimestamp, it.exitTimestamp)
days.removeAll(outsideDays)
days.removeAll(dates)
turnTimes << days.size()
}
The application is now crawling. I am obviously doing something wrong. When this is run for small data-sets it will complete slowly. On larger sets it doesn't finish. Prior to this change it was completing.

Answer 1

You can start with the lines of the below changes.
// Proposed
import static java.util.Calendar.*
// Query for all the children upfront instead of hitting
// database twice on each iteration.
// You can also avoid N + 1 situation if children is fetched eagerly
def allChildren = QueueEntry.where {
id in (result.processed*.id as List<Long>)
}.children.list()
def turnTimes = result.processed.collect { entry ->
allChildren.findAll { it.parent.id == entry.id }.collect { child ->
Set dates = []
new Date( child.entryTimeStamp ).upto( new Date( child.exitTimestamp ) ) {
if ( !( it[DAY_OF_WEEK] in [ SUNDAY, SATURDAY ] ) ) {
dates << it.time
}
}
Set outsideDays = child.numberOfDaysOutsideCVB
Set days =
DateUtils.businessDaysBetweenDates(
child.entryTimestamp,
child.exitTimestamp
)
( days - outsideDays - dates )?.size() ?: 0
}
}
Assumptions:
QueueEntry hasMany children
entryTimestamp/exitTimestamp is java.sql.Timestamp
entryTimestamp/exitTimestamp are not null and entryTimestamp comes before exitTimestamp.
As Burt suggested this question best fits in codereview.stackexchange.com