ITS#7491 check for filled dirty page list

Very large single transactions will fail. It's not just a problem when
nested transactions are used. We could make this dynamically sized,
but I'm not sure what the point is.

diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index 08aeca63b232f1787c0ee8c43a52da815ac168e5..bd10bb6bacf2e0fed0f63f7482a0dc8d8234b9f8 100644 (file)
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -346,7 +346,7 @@ typedef enum MDB_cursor_op {
 #define MDB_READERS_FULL       (-30790)
        /** Too many TLS keys in use - Windows only */
 #define MDB_TLS_FULL   (-30789)
-       /** Nested txn has too many dirty pages */
+       /** Txn has too many dirty pages */
 #define MDB_TXN_FULL   (-30788)
        /** Cursor stack too deep - internal error */
 #define MDB_CURSOR_FULL        (-30787)

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 710a59d44a7771483111d0bfa99f4508a5cdf324..67defdba2585ff511f0b4f265124e9cbf3617080 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1049,7 +1049,7 @@ static char *const mdb_errstr[] = {
        "MDB_DBS_FULL: Environment maxdbs limit reached",
        "MDB_READERS_FULL: Environment maxreaders limit reached",
        "MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
-       "MDB_TXN_FULL: Nested transaction has too many dirty pages - transaction too big",
+       "MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
        "MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
        "MDB_PAGE_FULL: Internal error - page has no more space"
 };
@@ -1225,6 +1225,14 @@ mdb_page_malloc(MDB_cursor *mc) {
        return ret;
 }
 
+static void
+mdb_page_free(MDB_env *env, MDB_page *mp)
+{
+       mp->mp_next = env->me_dpages;
+       VGMEMP_FREE(env, mp);
+       env->me_dpages = mp;
+}
+
 /** Allocate pages for writing.
  * If there are free pages available from older transactions, they
  * will be re-used first. Otherwise a new page will be allocated.
@@ -1246,6 +1254,11 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
        int rc;
 
        *mp = NULL;
+
+       /* If our dirty list is already full, we can't do anything */
+       if (txn->mt_u.dirty_list[0].mid >= MDB_IDL_UM_MAX)
+               return MDB_TXN_FULL;
+
        /* The free list won't have any content at all until txn 2 has
         * committed. The pages freed by txn 2 will be unreferenced
         * after txn 3 commits, and so will be safe to re-use in txn 4.
@@ -1596,6 +1609,8 @@ finish:
                                return 0;
                        }
                }
+               if (mc->mc_txn->mt_u.dirty_list[0].mid >= MDB_IDL_UM_MAX)
+                       return MDB_TXN_FULL;
                /* No - copy it */
                np = mdb_page_malloc(mc);
                if (!np)
@@ -1939,9 +1954,7 @@ mdb_txn_reset0(MDB_txn *txn)
                        for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
                                dp = txn->mt_u.dirty_list[i].mptr;
                                if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
-                                       dp->mp_next = txn->mt_env->me_dpages;
-                                       VGMEMP_FREE(txn->mt_env, dp);
-                                       txn->mt_env->me_dpages = dp;
+                                       mdb_page_free(txn->mt_env, dp);
                                } else {
                                        /* large pages just get freed directly */
                                        VGMEMP_FREE(txn->mt_env, dp);
@@ -2373,9 +2386,7 @@ again:
        for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
                dp = txn->mt_u.dirty_list[i].mptr;
                if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
-                       dp->mp_next = txn->mt_env->me_dpages;
-                       VGMEMP_FREE(txn->mt_env, dp);
-                       txn->mt_env->me_dpages = dp;
+                       mdb_page_free(txn->mt_env, dp);
                } else {
                        VGMEMP_FREE(txn->mt_env, dp);
                        free(dp);
@@ -6678,9 +6689,7 @@ newsep:
        }
 
        /* return tmp page to freelist */
-       copy->mp_next = mc->mc_txn->mt_env->me_dpages;
-       VGMEMP_FREE(mc->mc_txn->mt_env, copy);
-       mc->mc_txn->mt_env->me_dpages = copy;
+       mdb_page_free(mc->mc_txn->mt_env, copy);
 done:
        {
                /* Adjust other cursors pointing to mp */