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7 | 7 | * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group |
8 | 8 | * Portions Copyright (c) 1994, Regents of the University of California |
9 | 9 | * |
10 | | - * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.211 2005/07/29 03:22:33 momjian Exp $ |
| 10 | + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.212 2005/07/29 03:25:53 momjian Exp $ |
11 | 11 | * |
12 | 12 | *------------------------------------------------------------------------- |
13 | 13 | */ |
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54 | 54 | *with fsync(), but because skipping the kernel buffer forces writes out |
55 | 55 | *quickly, it seems best just to use it for O_SYNC. It is hard to imagine |
56 | 56 | *how fsync() could be a win for O_DIRECT compared to O_SYNC and O_DIRECT. |
| 57 | + *Also, O_DIRECT is never enough to force data to the drives, it merely |
| 58 | + *tries to bypass the kernel cache, so we still need O_SYNC or fsync(). |
57 | 59 | */ |
58 | 60 | #ifdefO_DIRECT |
59 | 61 | #definePG_O_DIRECTO_DIRECT |
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