Merge pull request #3594 from nichwall/filter_data_longer_cache

Increase cache time for `filterdata` in library

server/utils/queries/libraryFilters.js

@@ -459,10 +459,65 @@ module.exports = {
       languages: new Set(),
       publishers: new Set(),
       publishedDecades: new Set(),
+      bookCount: 0, // How many books returned from database query
+      authorCount: 0, // How many authors returned from database query
+      seriesCount: 0, // How many series returned from database query
+      podcastCount: 0, // How many podcasts returned from database query
       numIssues: 0
     }
 
+    const lastLoadedAt = cachedFilterData ? cachedFilterData.loadedAt : 0
+
     if (mediaType === 'podcast') {
+      // Check how many podcasts are in library to determine if we need to load all of the data
+      // This is done to handle the edge case of podcasts having been deleted and not having
+      // an updatedAt timestamp to trigger a reload of the filter data
+      const podcastCountFromDatabase = await Database.podcastModel.count({
+        include: {
+          model: Database.libraryItemModel,
+          attributes: [],
+          where: {
+            libraryId: libraryId
+          }
+        }
+      })
+
+      // To reduce the cold-start load time, first check if any podcasts
+      // have an "updatedAt" timestamp since the last time the filter
+      // data was loaded. If so, we can skip loading all of the data.
+      // Because many items could change, just check the count of items instead
+      // of actually loading the data twice
+      const changedPodcasts = await Database.podcastModel.count({
+        include: {
+          model: Database.libraryItemModel,
+          attributes: [],
+          where: {
+            libraryId: libraryId,
+            updatedAt: {
+              [Sequelize.Op.gt]: new Date(lastLoadedAt)
+            }
+          }
+        },
+        where: {
+          updatedAt: {
+            [Sequelize.Op.gt]: new Date(lastLoadedAt)
+          }
+        },
+        limit: 1
+      })
+
+      if (changedPodcasts === 0) {
+        // If nothing has changed, check if the number of podcasts in
+        // library is still the same as prior check before updating cache creation time
+
+        if (podcastCountFromDatabase === Database.libraryFilterData[libraryId].podcastCount) {
+          Logger.debug(`Filter data for ${libraryId} has not changed, returning cached data and updating cache time after ${((Date.now() - start) / 1000).toFixed(2)}s`)
+          Database.libraryFilterData[libraryId].loadedAt = Date.now()
+          return cachedFilterData
+        }
+      }
+
+      // Something has changed in the podcasts table, so reload all of the filter data for library
       const podcasts = await Database.podcastModel.findAll({
         include: {
           model: Database.libraryItemModel,
@@ -484,7 +539,93 @@ module.exports = {
           data.languages.add(podcast.language)
         }
       }
+
+      // Set podcast count for later comparison
+      data.podcastCount = podcastCountFromDatabase
     } else {
+      const bookCountFromDatabase = await Database.bookModel.count({
+        include: {
+          model: Database.libraryItemModel,
+          attributes: [],
+          where: {
+            libraryId: libraryId
+          }
+        }
+      })
+
+      const seriesCountFromDatabase = await Database.seriesModel.count({
+        where: {
+          libraryId: libraryId
+        }
+      })
+
+      const authorCountFromDatabase = await Database.authorModel.count({
+        where: {
+          libraryId: libraryId
+        }
+      })
+
+      // To reduce the cold-start load time, first check if any library items, series,
+      // or authors have an "updatedAt" timestamp since the last time the filter
+      // data was loaded. If so, we can skip loading all of the data.
+      // Because many items could change, just check the count of items instead
+      // of actually loading the data twice
+
+      const changedBooks = await Database.bookModel.count({
+        include: {
+          model: Database.libraryItemModel,
+          attributes: [],
+          where: {
+            libraryId: libraryId,
+            updatedAt: {
+              [Sequelize.Op.gt]: new Date(lastLoadedAt)
+            }
+          }
+        },
+        where: {
+          updatedAt: {
+            [Sequelize.Op.gt]: new Date(lastLoadedAt)
+          }
+        },
+        limit: 1
+      })
+
+      const changedSeries = await Database.seriesModel.count({
+        where: {
+          libraryId: libraryId,
+          updatedAt: {
+            [Sequelize.Op.gt]: new Date(lastLoadedAt)
+          }
+        },
+        limit: 1
+      })
+
+      const changedAuthors = await Database.authorModel.count({
+        where: {
+          libraryId: libraryId,
+          updatedAt: {
+            [Sequelize.Op.gt]: new Date(lastLoadedAt)
+          }
+        },
+        limit: 1
+      })
+
+      if (changedBooks + changedSeries + changedAuthors === 0) {
+        // If nothing has changed, check if the number of authors, series, and books
+        // matches the prior check before updating cache creation time
+        if (bookCountFromDatabase === Database.libraryFilterData[libraryId].bookCount && seriesCountFromDatabase === Database.libraryFilterData[libraryId].seriesCount && authorCountFromDatabase === Database.libraryFilterData[libraryId].authorCount) {
+          Logger.debug(`Filter data for ${libraryId} has not changed, returning cached data and updating cache time after ${((Date.now() - start) / 1000).toFixed(2)}s`)
+          Database.libraryFilterData[libraryId].loadedAt = Date.now()
+          return cachedFilterData
+        }
+      }
+
+      // Store the counts for later comparison
+      data.bookCount = bookCountFromDatabase
+      data.seriesCount = seriesCountFromDatabase
+      data.authorCount = authorCountFromDatabase
+
+      // Something has changed in one of the tables, so reload all of the filter data for library
       const books = await Database.bookModel.findAll({
         include: {
           model: Database.libraryItemModel,