updated docs

README.md

@@ -26,6 +26,29 @@ Monthly aggregation builds on daily summaries (or the daily rollup cache):
 - Monthly averages are `sum(weighted_sums) / monthly_total_samples` (per vCenter).
 - Pool percentages are weighted the same way: `(daily_pool_pct / 100) * daily_total_samples`, summed, then divided by `monthly_total_samples` and multiplied by 100.
 
+### Hourly Snapshot Fields
+Each hourly snapshot row tracks:
+- Identity: `InventoryId`, `Name`, `Vcenter`, `VmId`, `VmUuid`, `EventKey`, `CloudId`
+- Lifecycle/timing: `CreationTime`, `DeletionTime`, `SnapshotTime`
+- Placement: `ResourcePool`, `Datacenter`, `Cluster`, `Folder`
+- Sizing/state: `ProvisionedDisk`, `VcpuCount`, `RamGB`, `IsTemplate`, `PoweredOn`, `SrmPlaceholder`
+
+### Daily Aggregate Fields
+Daily summary rows retain identity/placement/sizing fields and add:
+- Sample coverage: `SamplesPresent`, `TotalSamples`, `AvgIsPresent`
+- Time-weighted sizing: `AvgVcpuCount`, `AvgRamGB`, `AvgProvisionedDisk`
+- Pool distribution percentages: `PoolTinPct`, `PoolBronzePct`, `PoolSilverPct`, `PoolGoldPct`
+- Chargeback totals columns: `Tin`, `Bronze`, `Silver`, `Gold`
+- Lifecycle carry-forward used by reports and trace: `CreationTime`, `DeletionTime`, `SnapshotTime`
+
+### Monthly Aggregate Fields
+Monthly summary rows keep the same aggregate fields as daily summaries and recompute them over the month:
+- `SamplesPresent` is summed across days.
+- Monthly averages (`AvgVcpuCount`, `AvgRamGB`, `AvgProvisionedDisk`) are weighted by each day's sample volume.
+- Monthly presence (`AvgIsPresent`) is normalized by monthly total samples.
+- Monthly pool percentages (`PoolTinPct`, `PoolBronzePct`, `PoolSilverPct`, `PoolGoldPct`) are weighted by each day’s sample volume before normalization.
+- `Tin`, `Bronze`, `Silver`, `Gold` totals remain available for reporting output.
+
 ## RPM Layout (summary)
 The RPM installs the service and defaults under `/usr/bin`, config under `/etc/dtms`, and data under `/var/lib/vctp`:
 - Binary: `/usr/bin/vctp-linux-amd64`