datastruct.go

package main

import "sort"

type Row struct {
	aggregatedTs string
	appName      string
	queryTxt     string
	prettyPlan   string
	iJoinStmt    int
	fullScan     int
	implicitTxn  int
	readsPerExec int
	lioAggTotal  int
	lioPct       float64
}

type RowLioSample struct {
	aggEpochSecs int
	lioTotal     int
	fullLio      int
	iJoinLio     int
	explicitLio  int
	healthyLio   int
}

type lessFunc func(p1, p2 *Row) bool

// multiSorter implements the Sort interface, sorting the changes within.
type multiSorter struct {
	changes []Row
	less    []lessFunc
}

// Less is part of sort.Interface. It is implemented by looping along the
// less functions until it finds a comparison that discriminates between
// the two items (one is less than the other). Note that it can call the
// less functions twice per call. We could change the functions to return
// -1, 0, 1 and reduce the number of calls for greater efficiency: an
// exercise for the reader.
func (ms *multiSorter) Less(i, j int) bool {
	p, q := &ms.changes[i], &ms.changes[j]
	// Try all but the last comparison.
	var k int
	for k = 0; k < len(ms.less)-1; k++ {
		less := ms.less[k]
		switch {
		case less(p, q):
			// p < q, so we have a decision.
			return true
		case less(q, p):
			// p > q, so we have a decision.
			return false
		}
		// p == q; try the next comparison.
	}
	// All comparisons to here said "equal", so just return whatever
	// the final comparison reports.
	return ms.less[k](p, q)
}

// Sort sorts the argument slice according to the less functions passed to OrderedBy.
func (ms *multiSorter) Sort(changes []Row) {
	ms.changes = changes
	sort.Sort(ms)
}

// Len is part of sort.Interface.
func (ms *multiSorter) Len() int {
	return len(ms.changes)
}

// Swap is part of sort.Interface.
func (ms *multiSorter) Swap(i, j int) {
	ms.changes[i], ms.changes[j] = ms.changes[j], ms.changes[i]
}

// OrderedBy returns a Sorter that sorts using the less functions, in order.
// Call its Sort method to sort the data.
func OrderedBy(less ...lessFunc) *multiSorter {
	return &multiSorter{
		less: less,
	}
}