From e0cbc201409706d4036b5a7280d2ef687b00557c Mon Sep 17 00:00:00 2001
From: Nathan Coad <nathan@thecoads.com>
Date: Mon, 9 Feb 2026 17:13:20 +1100
Subject: [PATCH] potential performance improvements for hourly inventory

---
 internal/tasks/inventorySnapshots.go | 41 ++++++++++++++++++++++------
 1 file changed, 33 insertions(+), 8 deletions(-)

diff --git a/internal/tasks/inventorySnapshots.go b/internal/tasks/inventorySnapshots.go
index bb071fa..3059a9e 100644
--- a/internal/tasks/inventorySnapshots.go
+++ b/internal/tasks/inventorySnapshots.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -164,6 +165,7 @@ func (c *CronTask) RunVcenterSnapshotHourly(ctx context.Context, logger *slog.Lo
 	if concurrencyLimit > 0 {
 		sem = make(chan struct{}, concurrencyLimit)
 	}
+	var deferredReportTables sync.Map
 	c.Logger.Info("Starting hourly snapshots", "vcenter_count", len(c.Settings.Values.Settings.VcenterAddresses), "concurrency_limit", concurrencyLimit)
 	for _, url := range c.Settings.Values.Settings.VcenterAddresses {
 		wg.Add(1)
@@ -182,7 +184,7 @@ func (c *CronTask) RunVcenterSnapshotHourly(ctx context.Context, logger *slog.Lo
 			defer cancel()
 
 			c.Logger.Info("Starting hourly snapshot for vcenter", "url", url)
-			if err := c.captureHourlySnapshotForVcenter(runCtx, startTime, tableName, url); err != nil {
+			if err := c.captureHourlySnapshotForVcenter(runCtx, startTime, tableName, url, &deferredReportTables); err != nil {
 				atomic.AddInt64(&errCount, 1)
 				c.Logger.Error("hourly snapshot failed", "error", err, "url", url)
 			} else {
@@ -211,6 +213,22 @@ func (c *CronTask) RunVcenterSnapshotHourly(ctx context.Context, logger *slog.Lo
 	}
 
 	metrics.RecordHourlySnapshot(startTime, rowCount, err)
+	var deferredTables []string
+	deferredReportTables.Range(func(key, _ interface{}) bool {
+		name, ok := key.(string)
+		if ok && strings.TrimSpace(name) != "" && name != tableName {
+			deferredTables = append(deferredTables, name)
+		}
+		return true
+	})
+	sort.Strings(deferredTables)
+	for _, reportTable := range deferredTables {
+		if err := c.generateReport(ctx, reportTable); err != nil {
+			c.Logger.Warn("failed to regenerate deferred hourly report after deletions", "error", err, "table", reportTable)
+		} else {
+			c.Logger.Debug("Regenerated deferred hourly report after deletions", "table", reportTable)
+		}
+	}
 	if err := c.generateReport(ctx, tableName); err != nil {
 		c.Logger.Warn("failed to generate hourly report", "error", err, "table", tableName)
 	}
@@ -277,7 +295,7 @@ func (c *CronTask) RunHourlySnapshotRetry(ctx context.Context, logger *slog.Logg
 			continue
 		}
 		logger.Info("Retrying hourly snapshot", "vcenter", f.Vcenter, "snapshot_time", startTime, "attempt", f.Attempts+1)
-		if err := c.captureHourlySnapshotForVcenter(ctx, startTime, tableName, f.Vcenter); err != nil {
+		if err := c.captureHourlySnapshotForVcenter(ctx, startTime, tableName, f.Vcenter, nil); err != nil {
 			logger.Warn("retry failed", "vcenter", f.Vcenter, "error", err)
 		}
 	}
@@ -1037,7 +1055,7 @@ func (c *CronTask) initVcenterResources(ctx context.Context, log *slog.Logger, u
 	return vc, res, cleanup, nil
 }
 
-func (c *CronTask) captureHourlySnapshotForVcenter(ctx context.Context, startTime time.Time, tableName string, url string) error {
+func (c *CronTask) captureHourlySnapshotForVcenter(ctx context.Context, startTime time.Time, tableName string, url string, deferredReportTables *sync.Map) error {
 	log := c.Logger.With("vcenter", url)
 	ctx = context.WithValue(ctx, ctxLoggerKey{}, log)
 	started := time.Now()
@@ -1356,11 +1374,18 @@ func (c *CronTask) captureHourlySnapshotForVcenter(ctx context.Context, startTim
 		if len(reportTables) == 0 {
 			reportTables[tableName] = struct{}{}
 		}
-		for reportTable := range reportTables {
-			if err := c.generateReport(ctx, reportTable); err != nil {
-				log.Warn("failed to regenerate hourly report after deletions", "error", err, "table", reportTable)
-			} else {
-				log.Debug("Regenerated hourly report after deletions", "table", reportTable)
+		if deferredReportTables != nil {
+			for reportTable := range reportTables {
+				deferredReportTables.Store(reportTable, struct{}{})
+			}
+			log.Debug("Queued hourly report regeneration after deletions", "tables", len(reportTables))
+		} else {
+			for reportTable := range reportTables {
+				if err := c.generateReport(ctx, reportTable); err != nil {
+					log.Warn("failed to regenerate hourly report after deletions", "error", err, "table", reportTable)
+				} else {
+					log.Debug("Regenerated hourly report after deletions", "table", reportTable)
+				}
 			}
 		}
 	}