BUG#15787 - MySQL crashes when archive table exceeds 2GB

Max compressed file size was calculated incorretly causing server
crash on INSERT.

With this patch we use proper max file size provided by zlib.

Affects 5.0 only.

mysql-test/r/archive-big.result

+CREATE TABLE t1(a BLOB) ENGINE=ARCHIVE;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+INSERT INTO t1 SELECT * FROM t1;
+DROP TABLE t1;

sql/ha_archive.cc

@@ -205,7 +205,7 @@ bool archive_db_init()
   else
   {
     zoffset_size= 2 << ((zlibCompileFlags() >> 6) & 3);
-    switch (sizeof(z_off_t)) {
+    switch (zoffset_size) {
     case 2:
       max_zfile_size= INT_MAX16;
       break;
@@ -676,6 +676,7 @@ int ha_archive::real_write_row(byte *buf, gzFile writer)
     total_row_length+= ((Field_blob*) table->field[*ptr])->get_length();
   if (share->approx_file_size > max_zfile_size - total_row_length)
   {
+    gzflush(writer, Z_SYNC_FLUSH);
     info(HA_STATUS_TIME);
     share->approx_file_size= (ulong) data_file_length;
     if (share->approx_file_size > max_zfile_size - total_row_length)