Add totalItems caching for server pagination to avoid redundant COUNT queries

[Copilot]

Server pagination currently requires calculating total item count on every page request. This adds a totalItems optimization that caches the count from the first request and reuses it, resetting only when search changes.

Changes

• Add totalItems state - Initialized to 0, stores total count across pagination requests
• Pass totalItems in onServerPage callback - Server receives cached count and can skip COUNT(*) on pages 2+
• Reset on search change - serverSearchForPagination() resets totalItems = 0 to force recalculation for filtered results
• Accept totalItems in setServerPaginatedOptions() - Third parameter stores count when provided by server

Server Implementation

function onServerPage(params, virtualSelect) {
  const { page, pageSize, searchValue, totalItems } = params;
  
  // Calculate only if totalItems is 0 (first request or search changed)
  const total = totalItems > 0 ? totalItems : await db.count({ search: searchValue });
  
  const results = await db.find({ search: searchValue })
    .skip((page - 1) * pageSize)
    .limit(pageSize);
  
  virtualSelect.setServerPaginatedOptions(results, page * pageSize < total, total);
}

Behavior

First page: totalItems: 0 → Server calculates → Returns 200
Page 2-N: totalItems: 200 → Server reuses → No COUNT query
Search changes: totalItems: 0 → Server recalculates → Returns filtered count

Screenshots

Initial load with optimization explanation:

Page 2 showing cached totalItems (no recalculation):

Search triggering totalItems reset and recalculation:

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.