Add maximum repair length to db_window (#1886)

* Add maximum repair length to db_window

src/db_window.rs

@@ -17,6 +17,8 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, RwLock};
 use streamer::BlobSender;
 
+pub const MAX_REPAIR_LENGTH: usize = 128;
+
 pub fn repair(
     slot: u64,
     db_ledger: &DbLedger,
@@ -79,7 +81,13 @@ pub fn repair(
         max_entry_height + 2
     };
 
-    let idxs = find_missing_data_indexes(slot, db_ledger, consumed, max_repair_entry_height - 1);
+    let idxs = find_missing_data_indexes(
+        slot,
+        db_ledger,
+        consumed,
+        max_repair_entry_height - 1,
+        MAX_REPAIR_LENGTH,
+    );
 
     let reqs: Vec<_> = idxs
         .into_iter()
@@ -117,8 +125,9 @@ pub fn find_missing_indexes(
     end_index: u64,
     key: &Fn(u64, u64) -> Vec<u8>,
     index_from_key: &Fn(&[u8]) -> Result<u64>,
+    max_missing: usize,
 ) -> Vec<u64> {
-    if start_index >= end_index {
+    if start_index >= end_index || max_missing == 0 {
         return vec![];
     }
 
@@ -129,7 +138,7 @@ pub fn find_missing_indexes(
 
     // The index of the first missing blob in the slot
     let mut prev_index = start_index;
-    loop {
+    'outer: loop {
         if !db_iterator.valid() {
             break;
         }
@@ -139,6 +148,9 @@ pub fn find_missing_indexes(
         let upper_index = cmp::min(current_index, end_index);
         for i in prev_index..upper_index {
             missing_indexes.push(i);
+            if missing_indexes.len() == max_missing {
+                break 'outer;
+            }
         }
         if current_index >= end_index {
             break;
@@ -156,6 +168,7 @@ pub fn find_missing_data_indexes(
     db_ledger: &DbLedger,
     start_index: u64,
     end_index: u64,
+    max_missing: usize,
 ) -> Vec<u64> {
     let mut db_iterator = db_ledger
         .db
@@ -169,6 +182,7 @@ pub fn find_missing_data_indexes(
         end_index,
         &DataCf::key,
         &DataCf::index_from_key,
+        max_missing,
     )
 }
 
@@ -177,6 +191,7 @@ pub fn find_missing_coding_indexes(
     db_ledger: &DbLedger,
     start_index: u64,
     end_index: u64,
+    max_missing: usize,
 ) -> Vec<u64> {
     let mut db_iterator = db_ledger
         .db
@@ -190,6 +205,7 @@ pub fn find_missing_coding_indexes(
         end_index,
         &ErasureCf::key,
         &ErasureCf::index_from_key,
+        max_missing,
     )
 }
 
@@ -463,9 +479,10 @@ mod test {
 
         // Early exit conditions
         let empty: Vec<u64> = vec![];
-        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 0, 0), empty);
+        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 0, 0, 1), empty);
-        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 5, 5), empty);
+        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 5, 5, 1), empty);
-        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 4, 3), empty);
+        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 4, 3, 1), empty);
+        assert_eq!(find_missing_data_indexes(slot, &db_ledger, 1, 2, 0), empty);
 
         let shared_blob = &make_tiny_test_entries(1).to_blobs()[0];
         let first_index = 10;
@@ -483,7 +500,13 @@ mod test {
         // given the input range of [i, first_index], the missing indexes should be
         // [i, first_index - 1]
         for i in 0..first_index {
-            let result = find_missing_data_indexes(slot, &db_ledger, i, first_index);
+            let result = find_missing_data_indexes(
+                slot,
+                &db_ledger,
+                i,
+                first_index,
+                (first_index - i) as usize,
+            );
             let expected: Vec<u64> = (i..first_index).collect();
 
             assert_eq!(result, expected);
@@ -503,6 +526,7 @@ mod test {
 
         // Write entries
         let gap = 10;
+        assert!(gap > 3);
         let num_entries = 10;
         let shared_blobs = make_tiny_test_entries(num_entries).to_blobs();
         for (b, i) in shared_blobs.iter().zip(0..shared_blobs.len() as u64) {
@@ -518,17 +542,29 @@ mod test {
         // range of [0, gap)
         let expected: Vec<u64> = (1..gap).collect();
         assert_eq!(
-            find_missing_data_indexes(slot, &db_ledger, 0, gap),
+            find_missing_data_indexes(slot, &db_ledger, 0, gap, gap as usize),
             expected
         );
         assert_eq!(
-            find_missing_data_indexes(slot, &db_ledger, 1, gap),
+            find_missing_data_indexes(slot, &db_ledger, 1, gap, (gap - 1) as usize),
             expected,
         );
         assert_eq!(
-            find_missing_data_indexes(slot, &db_ledger, 0, gap - 1),
+            find_missing_data_indexes(slot, &db_ledger, 0, gap - 1, (gap - 1) as usize),
             &expected[..expected.len() - 1],
         );
+        assert_eq!(
+            find_missing_data_indexes(slot, &db_ledger, gap - 2, gap, gap as usize),
+            vec![gap - 2, gap - 1],
+        );
+        assert_eq!(
+            find_missing_data_indexes(slot, &db_ledger, gap - 2, gap, 1),
+            vec![gap - 2],
+        );
+        assert_eq!(
+            find_missing_data_indexes(slot, &db_ledger, 0, gap, 1),
+            vec![1],
+        );
 
         for i in 0..num_entries as u64 {
             for j in 0..i {
@@ -539,7 +575,13 @@ mod test {
                         (begin..end)
                     }).collect();
                 assert_eq!(
-                    find_missing_data_indexes(slot, &db_ledger, j * gap, i * gap),
+                    find_missing_data_indexes(
+                        slot,
+                        &db_ledger,
+                        j * gap,
+                        i * gap,
+                        ((i - j) * gap) as usize
+                    ),
                     expected,
                 );
             }
@@ -567,7 +609,10 @@ mod test {
         let empty: Vec<u64> = vec![];
         for i in 0..num_entries as u64 {
             for j in 0..i {
-                assert_eq!(find_missing_data_indexes(slot, &db_ledger, j, i), empty);
+                assert_eq!(
+                    find_missing_data_indexes(slot, &db_ledger, j, i, (i - j) as usize),
+                    empty
+                );
             }
         }