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commit d2f4ff23fb8e50208ab396f6e87e09a7a4fa17a6
parent 03d4bc2044fdd032cb68702d94d0dde66fd5c4c9
Author: Christian Grothoff <christian@grothoff.org>
Date:   Sat, 10 Oct 2026 00:23:22 +0200

use static array for used_histories, instead of O(n^2) complexity

Diffstat:
M
src/auditor/taler-helper-auditor-coins.c
 | 
26
+++++++++++++++++---------

1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/src/auditor/taler-helper-auditor-coins.c b/src/auditor/taler-helper-auditor-coins.c
@@ -171,12 +171,17 @@ static struct CoinHistory coin_histories[MAX_COIN_HISTORIES];
 /**
  * Indices of the entries of #coin_histories that are in use.  Used to
  * flush the cache at the end of a pass without touching the entire
- * (huge) #coin_histories array.
+ * (huge) #coin_histories array.  An index is recorded only when its
+ * entry goes from empty to used, so there are never more than
+ * #MAX_COIN_HISTORIES of them.  Static rather than grown with
+ * GNUNET_array_append(): that copies the whole array on every call
+ * (quadratic in the number of coins of a pass) and aborts once the
+ * array exceeds GNUNET_MAX_MALLOC_CHECKED (about 10.5M entries).
  */
-static unsigned int *used_histories;
+static unsigned int used_histories[MAX_COIN_HISTORIES];
 
 /**
- * Length of the #used_histories array.
+ * Number of entries of #used_histories that are in use.
  */
 static unsigned int num_used_histories;
 
@@ -223,12 +228,17 @@ cache_history (const struct TALER_CoinSpendPublicKeyP *coin_pub,
 {
   unsigned int i = coin_history_index (coin_pub);
 
+  if (NULL == tl)
+    return; /* nothing to cache; get_cached_history() would miss anyway */
   if (NULL != coin_histories[i].tl)
+  {
     TALER_EXCHANGEDB_free_coin_transaction_list (coin_histories[i].tl);
+  }
   else
-    GNUNET_array_append (used_histories,
-                         num_used_histories,
-                         i);
+  {
+    GNUNET_assert (num_used_histories < MAX_COIN_HISTORIES);
+    used_histories[num_used_histories++] = i;
+  }
   coin_histories[i].coin_pub = *coin_pub;
   coin_histories[i].tl = tl;
 }
@@ -255,9 +265,7 @@ flush_coin_histories (void)
             0,
             sizeof (*ch));
   }
-  GNUNET_array_grow (used_histories,
-                     num_used_histories,
-                     0);
+  num_used_histories = 0;
 }