set @save_max_allowed_packet=@@max_allowed_packet; set global max_allowed_packet=1048576; connect conn1,localhost,root,,; connection conn1; select @test_compress_string:='string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa '; @test_compress_string:='string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ' string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa select length(@test_compress_string); length(@test_compress_string) 117 select uncompress(compress(@test_compress_string)); uncompress(compress(@test_compress_string)) string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa explain extended select uncompress(compress(@test_compress_string)); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used Warnings: Note 1003 select uncompress(compress(@`test_compress_string`)) AS `uncompress(compress(@test_compress_string))` select uncompressed_length(compress(@test_compress_string))=length(@test_compress_string); uncompressed_length(compress(@test_compress_string))=length(@test_compress_string) 1 explain extended select uncompressed_length(compress(@test_compress_string))=length(@test_compress_string); id select_type table type possible_keys key key_len ref rows filtered Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used Warnings: Note 1003 select uncompressed_length(compress(@`test_compress_string`)) = octet_length(@`test_compress_string`) AS `uncompressed_length(compress(@test_compress_string))=length(@test_compress_string)` select uncompressed_length(compress(@test_compress_string)); uncompressed_length(compress(@test_compress_string)) 117 select length(compress(@test_compress_string))