diff options
Diffstat (limited to 'src/include/access/nbtree.h')
| -rw-r--r-- | src/include/access/nbtree.h | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h index 1831c662162..a58048ace97 100644 --- a/src/include/access/nbtree.h +++ b/src/include/access/nbtree.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.97 2006/05/07 01:21:30 tgl Exp $ + * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.98 2006/05/08 00:00:10 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -19,6 +19,10 @@ #include "access/sdir.h" #include "access/xlogutils.h" + +/* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */ +typedef uint16 BTCycleId; + /* * BTPageOpaqueData -- At the end of every page, we store a pointer * to both siblings in the tree. This is used to do forward/backward @@ -31,6 +35,16 @@ * and status. If the page is deleted, we replace the level with the * next-transaction-ID value indicating when it is safe to reclaim the page. * + * We also store a "vacuum cycle ID". When a page is split while VACUUM is + * processing the index, a nonzero value associated with the VACUUM run is + * stored into both halves of the split page. (If VACUUM is not running, + * both pages receive zero cycleids.) This allows VACUUM to detect whether + * a page was split since it started, with a small probability of false match + * if the page was last split some exact multiple of 65536 VACUUMs ago. + * Also, during a split, the BTP_SPLIT_END flag is cleared in the left + * (original) page, and set in the right page, but only if the next page + * to its right has a different cycleid. + * * NOTE: the BTP_LEAF flag bit is redundant since level==0 could be tested * instead. */ @@ -45,6 +59,7 @@ typedef struct BTPageOpaqueData TransactionId xact; /* next transaction ID, if deleted */ } btpo; uint16 btpo_flags; /* flag bits, see below */ + BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */ } BTPageOpaqueData; typedef BTPageOpaqueData *BTPageOpaque; @@ -55,6 +70,7 @@ typedef BTPageOpaqueData *BTPageOpaque; #define BTP_DELETED (1 << 2) /* page has been deleted from tree */ #define BTP_META (1 << 3) /* meta-page */ #define BTP_HALF_DEAD (1 << 4) /* empty, but still in tree */ +#define BTP_SPLIT_END (1 << 5) /* rightmost page of split group */ /* @@ -492,6 +508,11 @@ extern bool _bt_checkkeys(IndexScanDesc scan, Page page, OffsetNumber offnum, ScanDirection dir, bool *continuescan); extern void _bt_killitems(IndexScanDesc scan, bool haveLock); +extern BTCycleId _bt_vacuum_cycleid(Relation rel); +extern BTCycleId _bt_start_vacuum(Relation rel); +extern void _bt_end_vacuum(Relation rel); +extern Size BTreeShmemSize(void); +extern void BTreeShmemInit(void); /* * prototypes for functions in nbtsort.c |