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9 | 9 | * |
10 | 10 | * |
11 | 11 | * IDENTIFICATION |
12 | | - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.112 2009/01/01 17:23:35 momjian Exp $ |
| 12 | + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.113 2009/05/05 19:02:22 tgl Exp $ |
13 | 13 | * |
14 | 14 | *NOTES |
15 | 15 | * Postgres btree pages look like ordinary relation pages.The opaque |
@@ -569,8 +569,12 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access) |
569 | 569 | * This is equivalent to _bt_relbuf followed by _bt_getbuf, with the |
570 | 570 | * exception that blkno may not be P_NEW. Also, if obuf is InvalidBuffer |
571 | 571 | * then it reduces to just _bt_getbuf; allowing this case simplifies some |
572 | | - * callers. The motivation for using this is to avoid two entries to the |
573 | | - * bufmgr when one will do. |
| 572 | + * callers. |
| 573 | + * |
| 574 | + * The original motivation for using this was to avoid two entries to the |
| 575 | + * bufmgr when one would do. However, now it's mainly just a notational |
| 576 | + * convenience. The only case where it saves work over _bt_relbuf/_bt_getbuf |
| 577 | + * is when the target page is the same one already in the buffer. |
574 | 578 | */ |
575 | 579 | Buffer |
576 | 580 | _bt_relandgetbuf(Relationrel,Bufferobuf,BlockNumberblkno,intaccess) |
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