Issue 48 in google-sparsehash: dense_hash_map fails for large data sets

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Status: New
Owner: ----

New issue 48 by rags.iyengar: dense_hash_map fails for large data sets
http://code.google.com/p/google-sparsehash/issues/detail?id=48

What steps will reproduce the problem?
1. populate a dense_hash_map<const char*, const char*> with 30,000 entries
2. the key is a 21 character long(e.g "ODBC456789.12/45-BA91")
3.
4.

What is the expected output? What do you see instead?
Calling map.find on a key I know was inserted should return the value.
instead find returns map.end

What version of the product are you using? On what operating system?
sparsehash-1.5.2 (dense_hash_map) on MSVC 7.1.6030

Please provide any additional information below.


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Comment #1 on issue 48 by rags.iyengar: dense_hash_map fails for large data
sets
http://code.google.com/p/google-sparsehash/issues/detail?id=48

Also, map.size() seems to have a ceiling of ~844.
I tried resize(100000) at startup but this only affects the load factor and
has no
bearing on the size.

Is there a way of increasing the number of buckets?
I'm only concerned with rapid lookups; don't really care for memory

[google-s...@googlecode.com]

Updates:
Status: Invalid
Labels: Type-Defect Priority-Medium

Comment #2 on issue 48 by csilvers: dense_hash_map fails for large data sets
http://code.google.com/p/google-sparsehash/issues/detail?id=48

You need to specify a hash function for char*. Otherwise, you're hashing
pointers,
which will not work as you want. See the first example in
http://google-sparsehash.googlecode.com/svn/trunk/doc/dense_hash_map.html

} I tried resize(100000) at startup but this only affects the load factor
and has no
} bearing on the size.

That's not correct. It actually does affect the size, but not the load
factor.

You can also try using the one-arg constructor where you pass in the size,
rather
than having to call resize after creating the object.