diff options
| -rw-r--r-- | src/include/config.h.in | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/src/include/config.h.in b/src/include/config.h.in index 481b646199..8e5b194145 100644 --- a/src/include/config.h.in +++ b/src/include/config.h.in @@ -282,7 +282,25 @@ */ /* #define PSQL_ALWAYS_GET_PASSWORDS */ -/* Undocumented "features"? */ +/* + * Use btree bulkload code: + * this code is moderately slow (~10% slower) compared to the regular + * btree (insertion) build code on sorted or well-clustered data. on + * random data, however, the insertion build code is unusable -- the + * difference on a 60MB heap is a factor of 15 because the random + * probes into the btree thrash the buffer pool. + * + * Great thanks to Paul M. Aoki (aoki@CS.Berkeley.EDU) + */ #define FASTBUILD /* access/nbtree/nbtsort.c */ +/* + * BTREE_VERSION_1: we must guarantee that all tuples in A LEVEL + * are unique, not in ALL INDEX. So, we can use bti_itup->t_tid + * as unique identifier for a given index tuple (logical position + * within a level) and take off bti_oid & bti_dummy (8 bytes total) + * from btree items. + */ +#define BTREE_VERSION_1 + #endif /* CONFIG_H */ |