To rebuild use: ALTER INDEX __NAME_OF_INDEX__ ON __NAME_OF_TABLE__ REBUILD or to reorganize use: ALTER INDEX __NAME_OF_INDEX__ ON __NAME_OF_TABLE__ REORGANIZE Reorganizing should be used at lower (<30%) fragmentations but only rebuilding (which is heavier to the database) cuts the fragmentation down to 0%. For further information see https://msdn.microsoft.com/en-us/library/ms189858.aspx
Ok, picked up the bait. This is on a system with Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz 4×5666.59 bogomips Linux meerkat 2.6.35-28-generic-pae #50-Ubuntu SMP Fri Mar 18 20:43:15 UTC 2011 i686 GNU/Linux gcc version 4.4.5 total used free shared buffers cached Mem: 8127172 4220560 3906612 0 374328 2748796 -/+ buffers/cache: 1097436 7029736 Swap: 0 … Read more
You know, I somewhat doubt the memory profiler here. The memory management system in .NET actually tries to defragment the heap for you by moving around memory (that’s why you need to pin memory for it to be shared with an external DLL). Large memory allocations taken over longer periods of time is prone to … Read more
External fragmentation Total memory space is enough to satisfy a request or to reside a process in it, but it is not contiguous so it can not be used. Internal fragmentation Memory block assigned to process is bigger. Some portion of memory is left unused as it can not be used by another process.
Imagine that you have a “large” (32 bytes) expanse of free memory: ———————————- | | ———————————- Now, allocate some of it (5 allocations): ———————————- |aaaabbccccccddeeee | ———————————- Now, free the first four allocations but not the fifth: ———————————- | eeee | ———————————- Now, try to allocate 16 bytes. Oops, I can’t, even though there’s nearly … Read more