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.


sql/ha_archive.cc:
  When calculating max compressed file size, use the real offset size
  that is provided by zlib, instead of sizeof(z_off_t), which may be
  different from actual offset size.
  
  When we're about to write and the data file is almost full flush gzio
  buffer to get accurate real file size.
mysql-test/r/archive-big.result:
  New BitKeeper file ``mysql-test/r/archive-big.result''
mysql-test/t/archive-big.test:
  New BitKeeper file ``mysql-test/t/archive-big.test''

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)