Configuration for best performance with concurrent access

Question

Could someone tell me the flags I need to specify to achieve the best BDB performance in a multithreaded (concurrent) environment?
I am using Hash type and have simple access protocol. Just key/value get/put and delete. I don't need transactions or recovery
I tried DB_CREATE | DB_INIT_MPOOL | DB_INIT_CDB | DB_THREAD env. open flags and DB_CREATE | DB_THREAD db open flags, but I can only achieve 10000 requests per second.
I can get up to 40000 RPS with a single thread and just DB_CREATE | DB_INIT_MPOOL for environment and DB_CREATE for database. That should be sufficient, but I need that performance in multithreaded environment.
I tried EnvOpenFlags = DB_CREATE | DB_INIT_MPOOL | DB_THREAD and DbOpenFlags = DB_CREATE | DB_THREAD, but I am getting the following errors on Put:
page 29778: illegal page type or format
PANIC: fatal region error detected; run recovery
PANIC: Invalid argument
If I add DB_INIT_LOCK to the EnvOpenFlags, I get deadlocks. I am not sure why I even getting them based on my access schema.
Thanks,
Igor

Answer 1

I am running test on 64 bit Windows 2003.
Data is accessed randomly, but in the test, I do only inserts. Data is just a list of key/value pairs. Key is int and Value is byte array or size 50 (but it could vary up to about 50000).
In production it could be around 30 database files (one database per file), but for the test I use only one file.
I don't have config.log file. I built only db_dll and db_stat projects in VSN2005 and I use it form C# code through managed C++ wrapper.
Here are the stats for the DB_CREATE | DB_INIT_MPOOL | DB_INIT_CDB | DB_THREAD set of flags:
db_stat -e =>
Tue Feb 06 09:44:37 2007 Local time
0x120897 Magic number
0 Panic value
4.5.20 Environment version
Mon Feb 05 17:57:21 2007 Creation time
0x440a8ca8 Environment ID
1 Primary region allocation and reference count mutex [0/0 0% !Own]
2 References
Thread status blocks:
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
33 Last allocated locker ID
0x7fffffff Current maximum unused locker ID
5 Number of lock modes
1000 Maximum number of locks possible
1000 Maximum number of lockers possible
1000 Maximum number of lock objects possible
3 Number of current locks
5 Maximum number of locks at any one time
4 Number of current lockers
6 Maximum number of lockers at any one time
2 Number of current lock objects
4 Maximum number of lock objects at any one time
6813619 Total number of locks requested
6813616 Total number of locks released
0 Total number of locks upgraded
12 Total number of locks downgraded
3262547 Lock requests not available due to conflicts, for which we waited
0 Lock requests not available due to conflicts, for which we did not wait
0 Number of deadlocks
0 Lock timeout value
0 Number of locks that have timed out
0 Transaction timeout value
0 Number of transactions that have timed out
536KB The size of the lock region
8090 The number of region locks that required waiting (0%)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
5GB 50MB Total cache size
1 Number of caches
5GB 50MB Pool individual cache size
0 Maximum memory-mapped file size
0 Maximum open file descriptors
0 Maximum sequential buffer writes
0 Sleep after writing maximum sequential buffers
0 Requested pages mapped into the process' address space
17M Requested pages found in the cache (99%)
25834 Requested pages not found in the cache
22234 Pages created in the cache
11856 Pages read into the cache
88248 Pages written from the cache to the backing file
0 Clean pages forced from the cache
0 Dirty pages forced from the cache
0 Dirty pages written by trickle-sync thread
34063 Current total page count
5424 Current clean page count
28639 Current dirty page count
786431 Number of hash buckets used for page location
17M Total number of times hash chains searched for a page (17031608)
1 The longest hash chain searched for a page
16M Total number of hash chain entries checked for page (16971686)
0 The number of hash bucket locks that required waiting (0%)
0 The maximum number of times any hash bucket lock was waited for (0%)
0 The number of region locks that required waiting (0%)
0 The number of buffers frozen
0 The number of buffers thawed
0 The number of frozen buffers freed
34100 The number of page allocations
0 The number of hash buckets examined during allocations
0 The maximum number of hash buckets examined for an allocation
0 The number of pages examined during allocations
0 The max number of pages examined for an allocation
0 Threads waited on page I/O
Pool File: data.bdb30
8192 Page size
0 Requested pages mapped into the process' address space
17M Requested pages found in the cache (99%)
25832 Requested pages not found in the cache
22234 Pages created in the cache
11854 Pages read into the cache
88240 Pages written from the cache to the backing file
Pool File: e:/BerkeleyDb\admin.bdb
8192 Page size
0 Requested pages mapped into the process' address space
19 Requested pages found in the cache (90%)
2 Requested pages not found in the cache
0 Pages created in the cache
2 Pages read into the cache
8 Pages written from the cache to the backing file
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
96MB 88KB Mutex region size
0 The number of region locks that required waiting (0%)
4 Mutex alignment
100 Mutex test-and-set spins
1574134 Mutex total count
1239 Mutex free count
1572895 Mutex in-use count
1572897 Mutex maximum in-use count
Mutex counts
1239 Unallocated
1 db handle
1 env dblist
1 env region
1 lock region
5 logical lock
2 mpoolfile handle
1 mpool filehandle
17 mpool file bucket
1 mpool handle
786431 mpool hash bucket
786431 mpool buffer I/O
1 mpool region
1 unknown mutex type
1 twister
db_stat -d =>
Tue Feb 06 09:46:42 2007 Local time
61561 Hash magic number
8 Hash version number
Little-endian Byte order
Flags
8192 Underlying database page size
0 Specified fill factor
6048411 Number of keys in the database
6048411 Number of data items in the database
27229 Number of hash buckets
14M Number of bytes free on bucket pages (93% ff)
0 Number of overflow pages
0 Number of bytes free in overflow pages (0% ff)
8438 Number of bucket overflow pages
30M Number of bytes free in bucket overflow pages (57% ff)
0 Number of duplicate pages
0 Number of bytes free in duplicate pages (0% ff)
1 Number of pages on the free list
db_stat -m =>
5GB 50MB Total cache size
1 Number of caches
5GB 50MB Pool individual cache size
0 Maximum memory-mapped file size
0 Maximum open file descriptors
0 Maximum sequential buffer writes
0 Sleep after writing maximum sequential buffers
0 Requested pages mapped into the process' address space
17M Requested pages found in the cache (99%)
27219 Requested pages not found in the cache
22444 Pages created in the cache
13241 Pages read into the cache
120831 Pages written from the cache to the backing file
0 Clean pages forced from the cache
0 Dirty pages forced from the cache
0 Dirty pages written by trickle-sync thread
35672 Current total page count
35658 Current clean page count
14 Current dirty page count
786431 Number of hash buckets used for page location
17M Total number of times hash chains searched for a page (17471571)
1 The longest hash chain searched for a page
17M Total number of hash chain entries checked for page (17408653)
0 The number of hash bucket locks that required waiting (0%)
0 The maximum number of times any hash bucket lock was waited for (0%)
0 The number of region locks that required waiting (0%)
0 The number of buffers frozen
0 The number of buffers thawed
0 The number of frozen buffers freed
35695 The number of page allocations
0 The number of hash buckets examined during allocations
0 The maximum number of hash buckets examined for an allocation
0 The number of pages examined during allocations
0 The max number of pages examined for an allocation
0 Threads waited on page I/O
Pool File: data.bdb30
8192 Page size
0 Requested pages mapped into the process' address space
17M Requested pages found in the cache (99%)
27217 Requested pages not found in the cache
22444 Pages created in the cache
13239 Pages read into the cache
120821 Pages written from the cache to the backing file
Pool File: e:/BerkeleyDb\admin.bdb
8192 Page size
0 Requested pages mapped into the process' address space
25 Requested pages found in the cache (92%)
2 Requested pages not found in the cache
0 Pages created in the cache
2 Pages read into the cache
10 Pages written from the cache to the backing file
db_stat -CA =>
Default locking region information:
39 Last allocated locker ID
0x7fffffff Current maximum unused locker ID
5 Number of lock modes
1000 Maximum number of locks possible
1000 Maximum number of lockers possible
1000 Maximum number of lock objects possible
0 Number of current locks
5 Maximum number of locks at any one time
0 Number of current lockers
6 Maximum number of lockers at any one time
0 Number of current lock objects
4 Maximum number of lock objects at any one time
6975306 Total number of locks requested
6975306 Total number of locks released
0 Total number of locks upgraded
15 Total number of locks downgraded
3423839 Lock requests not available due to conflicts, for which we waited
0 Lock requests not available due to conflicts, for which we did not wait
0 Number of deadlocks
0 Lock timeout value
0 Number of locks that have timed out
0 Transaction timeout value
0 Number of transactions that have timed out
536KB The size of the lock region
8274 The number of region locks that required waiting (0%)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock REGINFO information:
Lock Region type
4 Region ID
e:\BerkeleyDB\__db.004 Region name
0x90a0000 Original region address
0x90a0000 Region address
0x9125f00 Region primary address
0 Region maximum allocation
0 Region allocated
REGION_JOIN_OK Region flags
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock region parameters:
1572884 Lock region region mutex [8274/17M 0% 1552/2884]
1031 locker table size
1031 object table size
532064 obj_off
515560 locker_off
1 need_dd
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Lock conflict matrix:
0 0 0 0 0
0 0 1 0 0
0 1 1 1 1
0 0 0 0 0
0 0 1 0 1
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Locks grouped by lockers:
Locker Mode Count Status ----------------- Object ---------------
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Locks grouped by object:
Locker Mode Count Status ----------------- Object ---------------