DB-759 test and fix alter table bug with cardinality data

mysql-test/suite/tokudb/t/card_drop_index_2.test

+# test that add index keeps cardinality for older indexes
+
+source include/have_tokudb.inc;
+set default_storage_engine='tokudb';
+
+disable_warnings;
+drop table if exists tt;
+enable_warnings;
+
+create table tt (a int, b int, c int, primary key(a), key(b), key(c));
+let $a=0;
+while ($a < 500) {
+    eval insert into tt values ($a, $a, 0), ($a+1, $a, 0), ($a+2, $a, 0), ($a+3, $a, 0);
+    inc $a; inc $a; inc $a; inc $a;
+}
+select count(*) from tt;
+
+# compute cardinality
+show indexes from tt;
+analyze table tt;
+show indexes from tt;
+
+# drop key b
+alter table tt drop key b;
+show indexes from tt;
+
+# drop key c
+alter table tt drop key c;
+show indexes from tt;
+
+# test that cardinality is persistent
+flush tables;
+show indexes from tt;
+
+drop table tt;

storage/tokudb/ha_tokudb_alter_56.cc

@@ -528,7 +528,7 @@ bool ha_tokudb::inplace_alter_table(TABLE *altered_table, Alter_inplace_info *ha
         error = alter_table_expand_blobs(altered_table, ha_alter_info);
 
     if (error == 0 && ctx->reset_card) {
-        error = tokudb::set_card_from_status(share->status_block, ctx->alter_txn, table->s, altered_table->s);
+        error = tokudb::alter_card(share->status_block, ctx->alter_txn, table->s, altered_table->s);
     }
     if (error == 0 && ctx->optimize_needed) {
         error = do_optimize(ha_thd());

storage/tokudb/tests/card_test_alter.cc

@@ -357,6 +357,65 @@ static void test_drop_2(DB_ENV *env) {
     assert(error == 0);
 }
 
+static void test_drop_1_multiple_parts(DB_ENV *env) {
+    int error;
+
+    DB_TXN *txn = NULL;
+    error = env->txn_begin(env, NULL, &txn, 0);
+    assert(error == 0);
+
+    DB *status_db = NULL;
+    error = tokudb::create_status(env, &status_db, "status_drop_1_multiple_parts", txn);
+    assert(error == 0);
+
+    // define tables
+    const uint ta_keys = 3;
+    const uint ta_key_parts = 1+2+3;
+    const uint ta_rec_per_keys = ta_key_parts;
+    uint64_t ta_rec_per_key[ta_rec_per_keys] = {
+        1000, 2000, 2001, 3000, 3001, 3002,
+    };
+    KEY_INFO ta_key_info[ta_rec_per_keys] = {
+        { 0, 1, &ta_rec_per_key[0], (char *) "key_a" },
+        { 0, 2, &ta_rec_per_key[0+1], (char *) "key_b" },
+        { 0, 3, &ta_rec_per_key[0+1+2], (char *) "key_c" },
+    };
+    TABLE_SHARE ta = { MAX_KEY, ta_keys, ta_key_parts, ta_key_info };
+
+    const uint tb_keys = 2;
+    const uint tb_key_parts = 1+3;
+    const int tb_rec_per_keys = tb_key_parts;
+    uint64_t tb_rec_per_key[tb_rec_per_keys] = {
+        1000, 3000, 3001, 3002,
+    };
+    KEY_INFO tb_key_info[tb_rec_per_keys] = {
+        { 0, 1, &tb_rec_per_key[0], (char *) "key_a" },
+        { 0, 3, &tb_rec_per_key[0+1], (char *) "key_c" },
+    };
+    TABLE_SHARE tb = { MAX_KEY, tb_keys, tb_key_parts, tb_key_info };
+
+    // set initial cardinality
+    error = tokudb::set_card_in_status(status_db, txn, ta_rec_per_keys, ta_rec_per_key);
+    assert(error == 0);
+
+    error = tokudb::alter_card(status_db, txn, &ta, &tb);
+    assert(error == 0);
+
+    // verify
+    uint64_t current_rec_per_key[tb_rec_per_keys];
+    error = tokudb::get_card_from_status(status_db, txn, tb_rec_per_keys, current_rec_per_key);
+    assert(error == 0);
+    for (uint i = 0; i < tb_rec_per_keys; i++) {
+        assert(current_rec_per_key[i] == tb_rec_per_key[i]);
+    }
+
+    error = txn->commit(txn, 0);
+    assert(error == 0);
+
+    error = tokudb::close_status(&status_db);
+    assert(error == 0);
+}
+
 static void test_add_0(DB_ENV *env) {
     int error;
 
@@ -534,6 +593,65 @@ static void test_add_2(DB_ENV *env) {
     assert(error == 0);
 }
 
+static void test_add_0_multiple_parts(DB_ENV *env) {
+    int error;
+
+    DB_TXN *txn = NULL;
+    error = env->txn_begin(env, NULL, &txn, 0);
+    assert(error == 0);
+
+    DB *status_db = NULL;
+    error = tokudb::create_status(env, &status_db, "status_add_0_multiple_parts", txn);
+    assert(error == 0);
+
+    // define tables
+    const uint ta_keys = 2;
+    const uint ta_key_parts = 3+4;
+    const uint ta_rec_per_keys = ta_key_parts;
+    uint64_t ta_rec_per_key[ta_rec_per_keys] = {
+        2000, 2001, 2002, 3000, 3001, 3002, 3003,
+    };
+    KEY_INFO ta_key_info[ta_rec_per_keys] = {
+        { 0, 3, &ta_rec_per_key[0], (char *) "key_b" },
+        { 0, 4, &ta_rec_per_key[3], (char *) "key_c" },
+    };
+    TABLE_SHARE ta = { MAX_KEY, ta_keys, ta_key_parts, ta_key_info };
+
+    const uint tb_keys = 3;
+    const uint tb_key_parts = 2+3+4;
+    const int tb_rec_per_keys = tb_key_parts;
+    uint64_t tb_rec_per_key[tb_rec_per_keys] = {
+        0, 0 /*not computed*/, 2000, 2001, 2002, 3000, 3001, 3002, 3003,
+    };
+    KEY_INFO tb_key_info[tb_rec_per_keys] = {
+        { 0, 2, &tb_rec_per_key[0], (char *) "key_a" },
+        { 0, 3, &tb_rec_per_key[0+2], (char *) "key_b" },
+        { 0, 4, &tb_rec_per_key[0+2+3], (char *) "key_c" },
+    };
+    TABLE_SHARE tb = { MAX_KEY, tb_keys, tb_key_parts, tb_key_info };
+
+    // set initial cardinality
+    error = tokudb::set_card_in_status(status_db, txn, ta_rec_per_keys, ta_rec_per_key);
+    assert(error == 0);
+
+    error = tokudb::alter_card(status_db, txn, &ta, &tb);
+    assert(error == 0);
+
+    // verify
+    uint64_t current_rec_per_key[tb_rec_per_keys];
+    error = tokudb::get_card_from_status(status_db, txn, tb_rec_per_keys, current_rec_per_key);
+    assert(error == 0);
+    for (uint i = 0; i < tb_rec_per_keys; i++) {
+        assert(current_rec_per_key[i] == tb_rec_per_key[i]);
+    }
+
+    error = txn->commit(txn, 0);
+    assert(error == 0);
+
+    error = tokudb::close_status(&status_db);
+    assert(error == 0);
+}
+
 int main() {
     int error;
 
@@ -555,9 +673,11 @@ int main() {
     test_drop_0(env);
     test_drop_1(env);
     test_drop_2(env);
+    test_drop_1_multiple_parts(env);
     test_add_0(env);
     test_add_1(env);
     test_add_2(env);
+    test_add_0_multiple_parts(env);
 
     error = env->close(env, 0);
     assert(error == 0);

storage/tokudb/tokudb_card.h

@@ -174,9 +174,14 @@ namespace tokudb {
         return false;
     }
 
+    static void copy_card(uint64_t *dest, uint64_t *src, size_t n) {
+        for (size_t i = 0; i < n; i++)
+            dest[i] = src[i];
+    }
+
     // Altered table cardinality = select cardinality data from current table cardinality for keys that exist 
     // in the altered table and the current table.
-    int set_card_from_status(DB *status_db, DB_TXN *txn, TABLE_SHARE *table_share, TABLE_SHARE *altered_table_share) {
+    int alter_card(DB *status_db, DB_TXN *txn, TABLE_SHARE *table_share, TABLE_SHARE *altered_table_share) {
         int error;
         // read existing cardinality data from status
         uint table_total_key_parts = tokudb::compute_total_key_parts(table_share);
@@ -201,7 +206,7 @@ namespace tokudb {
                 uint ith_key_parts = get_key_parts(&altered_table_share->key_info[i]);
                 uint orig_key_index;
                 if (find_index_of_key(altered_table_share->key_info[i].name, table_share, &orig_key_index)) {
-                    memcpy(&altered_rec_per_key[next_key_parts], &rec_per_key[orig_key_offset[orig_key_index]], ith_key_parts);
+                    copy_card(&altered_rec_per_key[next_key_parts], &rec_per_key[orig_key_offset[orig_key_index]], ith_key_parts);
                 }
                 next_key_parts += ith_key_parts;
             }