blob: 062a0170ac85411751b5ee4e87aae054e03542b9 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
/*! @page tune_file_alloc File allocation
@section tuning_system_file_block_grow File growth
It's faster on some filesystems to grow a file in chunks rather than to
extend it a block at a time as new blocks are written. By configuring
the wiredtiger_open functions \c file_extend value, applications can
grow files ahead of the blocks being written.
@snippet ex_all.c Configure file_extend
The system calls used to extend files in chunks on some systems require
locking across the system call, which may decrease performance. Before
configuring a \c file_extend value, before and after throughput should
be carefully evaluated.
@section tuning_system_file_block_allocation File block allocation
By default, when file blocks are being reused, WiredTiger attempts to
avoid file fragmentation by selecting the smallest available block
rather than splitting a larger available block into two. The \c
block_allocation configuration string to WT_SESSION::create can be set
to \c first to change the algorithm to first-fit, that is, take the
first available block in the file. Applications where file size is more
of an issue than file fragmentation (for example, applications with
fixed-size blocks) might want to configure this way.
@snippet ex_all.c Configure block_allocation
*/
|
