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Bug #18539: uncompress(d) is null: impossible?

The UNCOMPRESS() function was not marked as maybe_null, even though
  it returns NULL on invalid data. This confused the optimizer.
This commit is contained in:
jimw@rama.(none)
2006-07-10 19:50:40 -07:00
parent 72fa4883cf
commit 9c18b5752c
3 changed files with 43 additions and 1 deletions

View File

@@ -79,3 +79,31 @@ uncompress(a) uncompressed_length(a)
NULL NULL
a 1
drop table t1;
create table t1 (a varchar(32) not null);
insert into t1 values ('foo');
explain select * from t1 where uncompress(a) is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
select * from t1 where uncompress(a) is null;
a
foo
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
explain select *, uncompress(a) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1
select *, uncompress(a) from t1;
a uncompress(a)
foo NULL
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
select *, uncompress(a), uncompress(a) is null from t1;
a uncompress(a) uncompress(a) is null
foo NULL 1
Warnings:
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
Error 1256 Uncompressed data size too large; the maximum size is 104857600 (probably, length of uncompressed data was corrupted)
drop table t1;
End of 5.0 tests