Bug 18620
| Summary: | strange values in float type columns | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | Slawomir Bialek <civic> |
| Component: | mysql | Assignee: | Patrick Macdonald <patrickm> |
| Status: | CLOSED RAWHIDE | QA Contact: | David Lawrence <dkl> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 7.0 | CC: | jakub |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2000-10-25 18:59:28 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 19604 | ||
| Bug Blocks: | |||
Hardly a bug... this is about as close to zero as you can get it. With floating point arithmetic you don't get exact answers (you can't represent an infinite amount of numbers in a finite numbers of bits). Granted, 0 can be represented exactly... but any operation to it, or yielding such a number would probably result in something similar to what you are seeing. OK, it happens with other values (like "1") as well - they're also the same number according to mysql. According to the reporter (private mail) the same package compiled on Red Hat Linux 6.2 also works (same mail). Jakub, could you take a look at it? Fixed in 3.23.26-1 which I plan on releasing as a bugfix update soonish - thanks a lot for the report. Sorry, not fixed in -1. Workaround is to compile with -O1 - we'll fix this after fixing the bug in the compiler. Fixed in 3.23.26-1.2, which includes the patch mentioned in bug #19604. It has been upstreamed, and I expect to release an errata later. |
mysql> create table test (col1 float8); Query OK, 0 rows affected (0.00 sec) mysql> insert into test values (0); Query OK, 1 row affected (0.00 sec) mysql> select * from test; +-----------------------+ | col1 | +-----------------------+ | 2.18942949477526e-314 | +-----------------------+ 1 row in set (0.00 sec) It could be glibc or gcc bug.