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select @test_compress_string:='string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ';
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@test_compress_string:='string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa '
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string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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select length(@test_compress_string);
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length(@test_compress_string)
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select uncompress(compress(@test_compress_string));
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uncompress(compress(@test_compress_string))
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string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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explain extended select uncompress(compress(@test_compress_string));
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
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Note 1003 /* select#1 */ select uncompress(compress((@`test_compress_string`))) AS `uncompress(compress(@test_compress_string))`
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select uncompressed_length(compress(@test_compress_string))=length(@test_compress_string);
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uncompressed_length(compress(@test_compress_string))=length(@test_compress_string)
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explain extended select uncompressed_length(compress(@test_compress_string))=length(@test_compress_string);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
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Note 1003 /* select#1 */ select (uncompressed_length(compress((@`test_compress_string`))) = length((@`test_compress_string`))) AS `uncompressed_length(compress(@test_compress_string))=length(@test_compress_string)`
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select uncompressed_length(compress(@test_compress_string));
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uncompressed_length(compress(@test_compress_string))
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select length(compress(@test_compress_string))<length(@test_compress_string);
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length(compress(@test_compress_string))<length(@test_compress_string)
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create table t1 (a text, b char(255), c char(4)) engine=myisam;
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insert into t1 (a,b,c) values (compress(@test_compress_string),compress(@test_compress_string),'d ');
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select uncompress(a) from t1;
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string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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select uncompress(b) from t1;
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string for test compress function aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
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select concat('|',c,'|') from t1;
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select uncompress("");
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select uncompress(compress(""));
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uncompress(compress(""))
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select uncompressed_length("");
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uncompressed_length("")
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create table t1 (a text);
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insert t1 values (compress(null)), ('A\0\0\0BBBBBBBB'), (compress(space(50000))), (space(50000));
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select length(a) from t1;
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select length(uncompress(a)) from t1;
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Warning 1259 ZLIB: Input data corrupted
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Warning 1256 Uncompressed data size too large; the maximum size is 4194304 (probably, length of uncompressed data was corrupted)
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set @@global.max_allowed_packet=1048576*100;
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select compress(repeat('aaaaaaaaaa', IF(XXX, 10, 10000000))) is null;
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compress(repeat('aaaaaaaaaa', IF(XXX, 10, 10000000))) is null
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set @@global.max_allowed_packet=default;
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create table t1(a blob);
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insert into t1 values(NULL), (compress('a'));
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select uncompress(a), uncompressed_length(a) from t1;
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uncompress(a) uncompressed_length(a)
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create table t1(a blob);
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insert into t1 values ('0'), (NULL), ('0');
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select compress(a), compress(a) from t1;
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select compress(a) is null from t1;
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create table t1 (a varchar(32) not null);
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insert into t1 values ('foo');
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explain select * from t1 where uncompress(a) is null;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 NULL
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Warning 1259 ZLIB: Input data corrupted
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select * from t1 where uncompress(a) is null;
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Warning 1259 ZLIB: Input data corrupted
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explain select *, uncompress(a) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 NULL
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select *, uncompress(a) from t1;
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Warning 1259 ZLIB: Input data corrupted
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select *, uncompress(a), uncompress(a) is null from t1;
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a uncompress(a) uncompress(a) is null
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Warning 1259 ZLIB: Input data corrupted
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Warning 1259 ZLIB: Input data corrupted
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CREATE TABLE t1 (c1 INT);
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INSERT INTO t1 VALUES (1), (1111), (11111);
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SELECT UNCOMPRESS(c1), UNCOMPRESSED_LENGTH(c1) FROM t1;
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UNCOMPRESS(c1) UNCOMPRESSED_LENGTH(c1)
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EXPLAIN EXTENDED SELECT * FROM (SELECT UNCOMPRESSED_LENGTH(c1) FROM t1) AS s;