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diff --git a/java/com/google/gerrit/index/IndexConfig.java b/java/com/google/gerrit/index/IndexConfig.java
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+++ b/java/com/google/gerrit/index/IndexConfig.java
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+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.auto.value.AutoValue;
+import java.util.function.IntConsumer;
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * Implementation-specific configuration for secondary indexes.
+ *
+ * <p>Contains configuration that is tied to a specific index implementation but is otherwise
+ * global, i.e. not tied to a specific {@link Index} and schema version.
+ */
+@AutoValue
+public abstract class IndexConfig {
+  private static final int DEFAULT_MAX_TERMS = 1024;
+
+  public static IndexConfig createDefault() {
+    return builder().build();
+  }
+
+  public static Builder fromConfig(Config cfg) {
+    Builder b = builder();
+    setIfPresent(cfg, "maxLimit", b::maxLimit);
+    setIfPresent(cfg, "maxPages", b::maxPages);
+    setIfPresent(cfg, "maxTerms", b::maxTerms);
+    return b;
+  }
+
+  private static void setIfPresent(Config cfg, String name, IntConsumer setter) {
+    int n = cfg.getInt("index", null, name, 0);
+    if (n != 0) {
+      setter.accept(n);
+    }
+  }
+
+  public static Builder builder() {
+    return new AutoValue_IndexConfig.Builder()
+        .maxLimit(Integer.MAX_VALUE)
+        .maxPages(Integer.MAX_VALUE)
+        .maxTerms(DEFAULT_MAX_TERMS)
+        .separateChangeSubIndexes(false);
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder maxLimit(int maxLimit);
+
+    public abstract int maxLimit();
+
+    public abstract Builder maxPages(int maxPages);
+
+    public abstract int maxPages();
+
+    public abstract Builder maxTerms(int maxTerms);
+
+    public abstract int maxTerms();
+
+    public abstract Builder separateChangeSubIndexes(boolean separate);
+
+    abstract IndexConfig autoBuild();
+
+    public IndexConfig build() {
+      IndexConfig cfg = autoBuild();
+      checkLimit(cfg.maxLimit(), "maxLimit");
+      checkLimit(cfg.maxPages(), "maxPages");
+      checkLimit(cfg.maxTerms(), "maxTerms");
+      return cfg;
+    }
+  }
+
+  private static void checkLimit(int limit, String name) {
+    checkArgument(limit > 0, "%s must be positive: %s", name, limit);
+  }
+
+  /**
+   * @return maximum limit supported by the underlying index, or limited for performance reasons.
+   */
+  public abstract int maxLimit();
+
+  /**
+   * @return maximum number of pages (limit / start) supported by the underlying index, or limited
+   *     for performance reasons.
+   */
+  public abstract int maxPages();
+
+  /**
+   * @return maximum number of total index query terms supported by the underlying index, or limited
+   *     for performance reasons.
+   */
+  public abstract int maxTerms();
+
+  /**
+   * @return whether different subsets of changes may be stored in different physical sub-indexes.
+   */
+  public abstract boolean separateChangeSubIndexes();
+}