diff --git a/src/main/java/com/github/dbmdz/solrocr/reader/BaseSourceReader.java b/src/main/java/com/github/dbmdz/solrocr/reader/BaseSourceReader.java
index b4c4c6e1..52b66aaf 100644
--- a/src/main/java/com/github/dbmdz/solrocr/reader/BaseSourceReader.java
+++ b/src/main/java/com/github/dbmdz/solrocr/reader/BaseSourceReader.java
@@ -23,21 +23,21 @@ public abstract class BaseSourceReader implements SourceReader {
    * Array with a slot for every possible section in the source, of which only {@link
    * BaseSourceReader#maxCacheEntries} slots will ever be non-null
    */
-  private CachedSection[] cache;
+  CachedSection[] cache;
   /**
    * Array of length {@link BaseSourceReader#maxCacheEntries} with the indexes of the sections that
    * are currently cached
    */
-  private int[] cachedSectionIdxes;
+  int[] cachedSectionIdxes;
 
-  private int cacheSlotsUsed = 0;
+  int cacheSlotsUsed = 0;
 
   private enum AdjustDirection {
     LEFT,
     RIGHT
   }
 
-  private static final class CachedSection {
+  static final class CachedSection {
     public final Section section;
     public long lastUsedTimestampNs;
 
diff --git a/src/main/java/solrocr/OcrHighlightComponent.java b/src/main/java/solrocr/OcrHighlightComponent.java
index 4fb599cc..7390ff63 100644
--- a/src/main/java/solrocr/OcrHighlightComponent.java
+++ b/src/main/java/solrocr/OcrHighlightComponent.java
@@ -91,12 +91,23 @@ public void inform(SolrCore core) {
         Integer.parseInt(info.attributes.getOrDefault("maxQueuedPerThread", "8"));
     int sectionReadSize =
         Integer.parseInt(info.attributes.getOrDefault("sectionReadSizeKiB", "8")) * 1024;
+    if (sectionReadSize <= 0) {
+      throw new SolrException(
+          SolrException.ErrorCode.SERVER_ERROR,
+          "Invalid sectionReadSizeKiB, must be > 0: " + sectionReadSize);
+    }
     int maxSectionCacheSize =
-        Integer.parseInt(info.attributes.getOrDefault("maxSectionCacheSizeKiB", "64")) * 1024;
+        Integer.parseInt(info.attributes.getOrDefault("maxSectionCacheSizeKiB", "-1"));
+    if (maxSectionCacheSize < 0) {
+      maxSectionCacheSize = sectionReadSize * 10;
+    }
 
     this.ocrHighlighter =
         new SolrOcrHighlighter(
-            numHlThreads, maxQueuedPerThread, sectionReadSize, maxSectionCacheSize);
+            numHlThreads,
+            maxQueuedPerThread,
+            sectionReadSize,
+            (int) Math.ceil((double) maxSectionCacheSize / sectionReadSize));
   }
 
   @Override
diff --git a/src/test/java/com/github/dbmdz/solrocr/reader/FileSourceReaderTest.java b/src/test/java/com/github/dbmdz/solrocr/reader/FileSourceReaderTest.java
index 766c4605..8b88bc10 100644
--- a/src/test/java/com/github/dbmdz/solrocr/reader/FileSourceReaderTest.java
+++ b/src/test/java/com/github/dbmdz/solrocr/reader/FileSourceReaderTest.java
@@ -19,6 +19,28 @@ class FileSourceReaderTest {
   private final SourcePointer pointer = SourcePointer.parse(filePath.toString());
   private final int maxCacheEntries = 10;
 
+  @Test
+  void shouldCacheSectionsProperly() throws IOException {
+    FileSourceReader reader = new FileSourceReader(filePath, pointer, 8192, 3);
+    reader.getAsciiSection(128);
+    assertThat(reader.cachedSectionIdxes).containsExactlyInAnyOrder(-1, -1, 0);
+    assertThat(reader.cache[0].section.start).isEqualTo(0);
+    assertThat(reader.cache[0].section.end).isEqualTo(8192);
+    reader.getAsciiSection(8192 + 128);
+    assertThat(reader.cachedSectionIdxes).containsExactlyInAnyOrder(-1, 1, 0);
+    assertThat(reader.cache[1]).isNotNull();
+    reader.getAsciiSection(2 * 8192 + 128);
+    assertThat(reader.cachedSectionIdxes).containsExactlyInAnyOrder(2, 1, 0);
+    assertThat(reader.cache[2]).isNotNull();
+    // Test cache eviction
+    reader.getAsciiSection(3 * 8192 + 128);
+    assertThat(reader.cachedSectionIdxes).containsExactlyInAnyOrder(2, 1, 3);
+    assertThat(reader.cache[0]).isNull();
+    reader.getAsciiSection(16 * 8192 + 128);
+    assertThat(reader.cachedSectionIdxes).containsExactlyInAnyOrder(2, 16, 3);
+    assertThat(reader.cache[1]).isNull();
+  }
+
   @Test
   void shouldReadUtf8StringCorrectly() throws IOException {
     SourceReader reader = new FileSourceReader(filePath, pointer, 8192, maxCacheEntries);