Waits Related to Initialization Parameters

Wait Problem: Potential Fix
Free buffer: Increase the DB_CACHE_SIZE; shorten the checkpoint; tune the code
Buffer busy:  Segment Header — Add freelists or freelist groups or use ASSM
Buffer busy:  Data Block — Separate hot data; use reverse key indexes; small block sizes
Buffer busy:  Data Block — Increase initrans and/or maxtrans
Buffer busy:  Undo Header —Use automatic undo management
Buffer busy:  Undo Block — Commit more; use automatic undo management
Latch free:  Investigate the detail (listing in next table of this chapter for fixes)
Log buffer space: Increase the log buffer; use faster disks for the redo logs
Scattered read: Indicates many full table scans — tune the code; cache small tables
Sequential read: Indicates many index reads — tune the code (especially joins)
Write complete waits: Adds database writers; checkpoint more often; buffer cache too small

Latch Problem: Potential Fix

Library cache:  Use bind variables; adjust the shared_pool_size
Shared pool:  Use bind variables; adjust the shared_pool_size
Row cache objects: Increase the shared pool. This is not a common problem.
Cache buffers chain:  If you get this latch wait, it means you need to reduce logical I/O rates by tuning and minimizing the I/O requirements of the SQL involved. High I/O rates could be a sign of a hot block (meaning
a block highly accessed). Cache buffer lru chain latch contention can be resolved by increasing the size of the buffer cache and thereby reducing the rate at which new blocks are introduced into the buffer cache. You should adjust DB_BLOCK_BUFFERS, and possible DB_BLOCK_SIZE. Multiple buffer pools can help
reduce contention on this latch. You can create additional cache buffer lru chain latches by adjusting the configuration parameter DB_BLOCK_LRU_LATCHES. You may be able to reduce the load on the cache buffer chain latches by increasing the configuration parameter. _DB_BLOCK_HASH_BUCKETS may need to be increased or set to a prime number (in pre-9i versions).