diff --git a/apps/datapuller/src/pullers/classes.ts b/apps/datapuller/src/pullers/classes.ts
index f7619a380..cf5c2b82e 100644
--- a/apps/datapuller/src/pullers/classes.ts
+++ b/apps/datapuller/src/pullers/classes.ts
@@ -1,3 +1,5 @@
+import { connection } from "mongoose";
+
 import { ClassModel, TermModel } from "@repo/common";
 
 import { warmCatalogCacheForTerms } from "../lib/cache-warming";
@@ -98,53 +100,63 @@ const updateClasses = async (config: Config, termSelector: TermSelector) => {
 
   let totalClasses = 0;
   let totalInserted = 0;
+  let totalDeleted = 0;
+
+  // Insert classes in batches of 4 terms
   for (let i = 0; i < terms.length; i += TERMS_PER_API_BATCH) {
     const termsBatch = terms.slice(i, i + TERMS_PER_API_BATCH);
     const termsBatchIds = termsBatch.map((term) => term.id);
-
-    log.trace(
-      `Fetching classes for term ${termsBatch.map((term) => term.name).toLocaleString()}...`
-    );
-
-    const classes = await getClasses(
-      log,
-      CLASS_APP_ID,
-      CLASS_APP_KEY,
-      termsBatchIds
-    );
-
-    log.info(`Fetched ${classes.length.toLocaleString()} classes.`);
-    if (classes.length === 0) {
-      log.error(`No classes found, skipping update.`);
-      return;
-    }
-    totalClasses += classes.length;
-
-    log.trace("Deleting classes to be replaced...");
-
-    const { deletedCount } = await ClassModel.deleteMany({
-      termId: { $in: termsBatchIds },
-    });
-
-    log.info(`Deleted ${deletedCount.toLocaleString()} classes.`);
-
-    // Insert classes in batches of 5000
-    const insertBatchSize = 5000;
-    for (let i = 0; i < classes.length; i += insertBatchSize) {
-      const batch = classes.slice(i, i + insertBatchSize);
-
-      log.trace(`Inserting batch ${i / insertBatchSize + 1}...`);
-
-      const { insertedCount } = await ClassModel.insertMany(batch, {
-        ordered: false,
-        rawResult: true,
+    const session = await connection.startSession();
+    try {
+      await session.withTransaction(async () => {
+        log.trace(
+          `Fetching classes for terms ${termsBatch.map((term) => term.name).toLocaleString()}...`
+        );
+        const classes = await getClasses(
+          log,
+          CLASS_APP_ID,
+          CLASS_APP_KEY,
+          termsBatchIds
+        );
+
+        if (classes.length === 0) {
+          throw new Error(`No classes found, skipping update.`);
+        }
+
+        log.trace(`Deleting classes in batch ${i}...`);
+
+        const { deletedCount } = await ClassModel.deleteMany({
+          termId: { $in: termsBatchIds },
+        });
+
+        log.trace(`Inserting batch ${i}`);
+
+        const { insertedCount } = await ClassModel.insertMany(classes, {
+          ordered: false,
+          rawResult: true,
+        });
+
+        // avoid replacing data if a non-negligible amount is deleted
+        if (insertedCount / deletedCount <= 0.9) {
+          throw new Error(
+            `Deleted ${deletedCount} classes and inserted only ${insertedCount} in batch ${i}; aborting data insertion process`
+          );
+        }
+
+        totalClasses += classes.length;
+        totalDeleted += deletedCount;
+        totalInserted += insertedCount;
       });
-      totalInserted += insertedCount;
+    } catch (error: any) {
+      log.error(`Error inserting batch: ${error.message}`);
+    } finally {
+      await session.endSession();
     }
   }
 
+  log.info(`Deleted ${totalDeleted.toLocaleString()} total classes`);
   log.info(
-    `Completed updating database with ${totalClasses.toLocaleString()} classes, inserted ${totalInserted.toLocaleString()} documents.`
+    `Inserted ${totalInserted.toLocaleString()} classes, after fetching ${totalClasses.toLocaleString()} classes.`
   );
 
   await updateTermsCatalogDataFlags(log);
diff --git a/apps/datapuller/src/pullers/courses.ts b/apps/datapuller/src/pullers/courses.ts
index 78cf71733..48d186e41 100644
--- a/apps/datapuller/src/pullers/courses.ts
+++ b/apps/datapuller/src/pullers/courses.ts
@@ -21,6 +21,15 @@ const updateCourses = async (config: Config) => {
 
   log.trace("Deleting courses no longer in SIS...");
 
+  const previousCourses = await CourseModel.countDocuments();
+
+  if (courses.length / previousCourses <= 0.95) {
+    log.error(
+      `Fetched only ${courses.length} courses, while there were ${previousCourses} previous courses`
+    );
+    return;
+  }
+
   const { deletedCount } = await CourseModel.deleteMany({
     courseId: { $nin: courses.map((course) => course.courseId) },
   });
diff --git a/apps/datapuller/src/pullers/grade-distributions.ts b/apps/datapuller/src/pullers/grade-distributions.ts
index 6666b26ef..04b1caf74 100644
--- a/apps/datapuller/src/pullers/grade-distributions.ts
+++ b/apps/datapuller/src/pullers/grade-distributions.ts
@@ -1,3 +1,5 @@
+import { connection } from "mongoose";
+
 import {
   CourseModel,
   GradeCounts,
@@ -14,7 +16,7 @@ import {
   getRecentPastTerms,
 } from "../shared/term-selectors";
 
-const TERMS_PER_API_BATCH = 100;
+const TERMS_PER_API_BATCH = 50;
 
 interface AggregatedCourseGradeSummary extends GradeCounts {
   _id: {
@@ -141,54 +143,72 @@ const updateGradeDistributions = async (
 
   let totalGradeDistributions = 0;
   let totalInserted = 0;
+  let totalDeleted = 0;
+
+  // Insert grade distributions in batches of 50 terms
   for (let i = 0; i < terms.length; i += TERMS_PER_API_BATCH) {
     const termsBatch = terms.slice(i, i + TERMS_PER_API_BATCH);
     const termsBatchIds = termsBatch.map((term) => term.id);
-
-    log.trace(
-      `Fetching grade distributions for term ${termsBatch.map((term) => term.name).toLocaleString()}...`
-    );
-
-    const gradeDistributions = await getGradeDistributionDataByTerms(
-      DATABASE,
-      S3_OUTPUT,
-      REGION_NAME,
-      WORKGROUP,
-      termsBatchIds
-    );
-
-    log.info(
-      `Fetched ${gradeDistributions.length.toLocaleString()} grade distributions.`
-    );
-    if (gradeDistributions.length === 0) {
-      log.error("No grade distributions found, skipping update");
-      return;
-    }
-
-    log.trace("Deleting grade distributions to be replaced...");
-
-    const { deletedCount } = await GradeDistributionModel.deleteMany({
-      termId: { $in: termsBatchIds },
-    });
-
-    log.info(`Deleted ${deletedCount.toLocaleString()} grade distributions.`);
-
-    // Insert grade distributions in batches of 5000
-    let totalInserted = 0;
-    const insertBatchSize = 5000;
-    for (let i = 0; i < gradeDistributions.length; i += insertBatchSize) {
-      const batch = gradeDistributions.slice(i, i + insertBatchSize);
-
-      log.trace(`Inserting batch ${i / insertBatchSize + 1}`);
-
-      const { insertedCount } = await GradeDistributionModel.insertMany(batch, {
-        ordered: false,
-        rawResult: true,
+    const session = await connection.startSession();
+    try {
+      await session.withTransaction(async () => {
+        log.trace(
+          `Fetching grade distributions for terms ${termsBatch.map((term) => term.name).toLocaleString()}...`
+        );
+
+        const gradeDistributions = await getGradeDistributionDataByTerms(
+          DATABASE,
+          S3_OUTPUT,
+          REGION_NAME,
+          WORKGROUP,
+          termsBatchIds
+        );
+
+        log.info(
+          `Fetched ${gradeDistributions.length.toLocaleString()} grade distributions.`
+        );
+
+        if (gradeDistributions.length === 0) {
+          throw new Error(`No grade distributions found, skipping update`);
+        }
+
+        log.trace("Deleting grade distributions to be replaced...");
+
+        const { deletedCount } = await GradeDistributionModel.deleteMany({
+          termId: { $in: termsBatchIds },
+        });
+
+        log.trace(`Inserting batch ${i}`);
+
+        const { insertedCount } = await GradeDistributionModel.insertMany(
+          gradeDistributions,
+          {
+            ordered: false,
+            rawResult: true,
+          }
+        );
+
+        // avoid replacing data if a non-negligible amount is deleted
+        if (insertedCount / deletedCount <= 0.9) {
+          throw new Error(
+            `Deleted ${deletedCount} grade distributions and inserted only ${insertedCount} in batch ${i}; aborting data insertion process`
+          );
+        }
+
+        totalDeleted += deletedCount;
+        totalInserted += insertedCount;
+        totalGradeDistributions += gradeDistributions.length;
       });
-      totalInserted += insertedCount;
+    } catch (error: any) {
+      log.error(`Error inserting batch: ${error.message}`);
+    } finally {
+      await session.endSession();
     }
   }
 
+  log.info(
+    `Deleted ${totalDeleted.toLocaleString()} total grade distributions`
+  );
   log.info(
     `Completed updating database with ${totalGradeDistributions.toLocaleString()} grade distributions, inserted ${totalInserted.toLocaleString()} documents.`
   );
diff --git a/apps/datapuller/src/pullers/sections.ts b/apps/datapuller/src/pullers/sections.ts
index 65294d543..15c9525a7 100644
--- a/apps/datapuller/src/pullers/sections.ts
+++ b/apps/datapuller/src/pullers/sections.ts
@@ -1,3 +1,5 @@
+import { connection } from "mongoose";
+
 import { SectionModel } from "@repo/common";
 
 import { getSections } from "../lib/sections";
@@ -31,51 +33,63 @@ const updateSections = async (config: Config, termSelector: TermSelector) => {
 
   let totalSections = 0;
   let totalInserted = 0;
+  let totalDeleted = 0;
+
   for (let i = 0; i < terms.length; i += TERMS_PER_API_BATCH) {
     const termsBatch = terms.slice(i, i + TERMS_PER_API_BATCH);
     const termsBatchIds = termsBatch.map((term) => term.id);
-
-    log.trace(
-      `Fetching sections for term ${termsBatch.map((term) => term.name).toLocaleString()}...`
-    );
-
-    const sections = await getSections(
-      log,
-      CLASS_APP_ID,
-      CLASS_APP_KEY,
-      termsBatchIds
-    );
-
-    log.info(`Fetched ${sections.length.toLocaleString()} sections.`);
-    if (sections.length === 0) {
-      log.error(`No sections found, skipping update.`);
-      return;
-    }
-    totalSections += sections.length;
-
-    log.trace("Deleting sections to be replaced...");
-
-    const { deletedCount } = await SectionModel.deleteMany({
-      termId: { $in: termsBatchIds },
-    });
-
-    log.info(`Deleted ${deletedCount.toLocaleString()} sections.`);
-
-    // Insert sections in batches of 5000
-    const insertBatchSize = 5000;
-    for (let i = 0; i < sections.length; i += insertBatchSize) {
-      const batch = sections.slice(i, i + insertBatchSize);
-
-      log.trace(`Inserting batch ${i / insertBatchSize + 1}...`);
-
-      const { insertedCount } = await SectionModel.insertMany(batch, {
-        ordered: false,
-        rawResult: true,
+    const session = await connection.startSession();
+    try {
+      await session.withTransaction(async () => {
+        log.trace(
+          `Fetching sections for terms ${termsBatch.map((term) => term.name).toLocaleString()}...`
+        );
+
+        const sections = await getSections(
+          log,
+          CLASS_APP_ID,
+          CLASS_APP_KEY,
+          termsBatchIds
+        );
+
+        log.info(`Fetched ${sections.length.toLocaleString()} sections.`);
+
+        if (sections.length === 0) {
+          throw new Error(`No sections found, skipping update`);
+        }
+
+        log.trace("Deleting sections to be replaced...");
+
+        const { deletedCount } = await SectionModel.deleteMany({
+          termId: { $in: termsBatchIds },
+        });
+
+        log.trace(`Inserting batch ${i}`);
+
+        const { insertedCount } = await SectionModel.insertMany(sections, {
+          ordered: false,
+          rawResult: true,
+        });
+
+        // avoid replacing data if a non-negligible amount is deleted
+        if (insertedCount / deletedCount <= 0.9) {
+          throw new Error(
+            `Deleted ${deletedCount} sections and inserted only ${insertedCount} in batch ${i}; aborting data insertion process`
+          );
+        }
+
+        totalDeleted += deletedCount;
+        totalInserted += insertedCount;
+        totalSections += sections.length;
       });
-      totalInserted += insertedCount;
+    } catch (error: any) {
+      log.error(`Error inserting batch: ${error.message}`);
+    } finally {
+      await session.endSession();
     }
   }
 
+  log.info(`Deleted ${totalDeleted.toLocaleString()} total sections`);
   log.info(
     `Completed updating database with ${totalSections.toLocaleString()} sections, inserted ${totalInserted.toLocaleString()} documents.`
   );