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path: root/db2/btree/bt_cursor.c
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Diffstat (limited to 'db2/btree/bt_cursor.c')
-rw-r--r--db2/btree/bt_cursor.c152
1 files changed, 81 insertions, 71 deletions
diff --git a/db2/btree/bt_cursor.c b/db2/btree/bt_cursor.c
index a1266bcd3c..e5f3faeb70 100644
--- a/db2/btree/bt_cursor.c
+++ b/db2/btree/bt_cursor.c
@@ -8,7 +8,7 @@
#include "config.h"
#ifndef lint
-static const char sccsid[] = "@(#)bt_cursor.c 10.33 (Sleepycat) 9/24/97";
+static const char sccsid[] = "@(#)bt_cursor.c 10.35 (Sleepycat) 10/25/97";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
@@ -62,10 +62,10 @@ __bam_cursor(dbp, txn, dbcp)
DEBUG_LWRITE(dbp, txn, "bam_cursor", NULL, NULL, 0);
- if ((dbc = (DBC *)calloc(1, sizeof(DBC))) == NULL)
+ if ((dbc = (DBC *)__db_calloc(1, sizeof(DBC))) == NULL)
return (ENOMEM);
- if ((cp = (CURSOR *)calloc(1, sizeof(CURSOR))) == NULL) {
- free(dbc);
+ if ((cp = (CURSOR *)__db_calloc(1, sizeof(CURSOR))) == NULL) {
+ __db_free(dbc);
return (ENOMEM);
}
@@ -474,7 +474,7 @@ __bam_c_rget(dbp, cp, key, data, flags)
__bam_stkrel(dbp);
err: (void)memp_fput(dbp->mpf, cp->page, 0);
- free(dbt.data);
+ __db_free(dbt.data);
return (ret);
}
@@ -1422,7 +1422,7 @@ __bam_c_physdel(dbp, cp, h)
DB_LOCK lock;
db_indx_t indx;
db_pgno_t pgno, next_pgno, prev_pgno;
- int local, ret;
+ int local, normal, ret;
t = dbp->internal;
ret = 0;
@@ -1457,51 +1457,65 @@ __bam_c_physdel(dbp, cp, h)
local = 0;
/*
- * If we're deleting a duplicate entry, call the common code to do
- * the work.
+ * If we're deleting a duplicate entry and there are other duplicate
+ * entries remaining, call the common code to do the work and fix up
+ * the parent page as necessary. Otherwise, do a normal btree delete.
+ *
+ * There are 5 possible cases:
+ *
+ * 1. It's not a duplicate item: do a normal btree delete.
+ * 2. It's a duplicate item:
+ * 2a: We delete an item from a page of duplicates, but there are
+ * more items on the page.
+ * 2b: We delete the last item from a page of duplicates, deleting
+ * the last duplicate.
+ * 2c: We delete the last item from a page of duplicates, but there
+ * is a previous page of duplicates.
+ * 2d: We delete the last item from a page of duplicates, but there
+ * is a following page of duplicates.
+ *
+ * In the case of:
+ *
+ * 1: There's nothing further to do.
+ * 2a: There's nothing further to do.
+ * 2b: Do the normal btree delete instead of a duplicate delete, as
+ * that deletes both the duplicate chain and the parent page's
+ * entry.
+ * 2c: There's nothing further to do.
+ * 2d: Delete the duplicate, and update the parent page's entry.
*/
if (TYPE(h) == P_DUPLICATE) {
pgno = PGNO(h);
prev_pgno = PREV_PGNO(h);
next_pgno = NEXT_PGNO(h);
- if ((ret = __db_drem(dbp, &h, indx, __bam_free)) != 0)
- goto err;
- /*
- * There are 4 cases:
- *
- * 1. We removed an item on a page, but there are more items
- * on the page.
- * 2. We removed the last item on a page, removing the last
- * duplicate.
- * 3. We removed the last item on a page, but there is a
- * following page of duplicates.
- * 4. We removed the last item on a page, but there is a
- * previous page of duplicates.
- *
- * In case 1, h != NULL, h->pgno == pgno
- * In case 2, h == NULL,
- * prev_pgno == PGNO_INVALID, next_pgno == PGNO_INVALID
- * In case 3, h != NULL, next_pgno != PGNO_INVALID
- * In case 4, h == NULL, prev_pgno != PGNO_INVALID
- *
- * In case 1, there's nothing else to do.
- * In case 2, remove the entry from the parent page.
- * In case 3 or 4, if the deleted page was the first in a chain
- * of duplicate pages, update the parent page's entry.
- *
- * Test:
- * If there were previous pages of duplicates or we didn't
- * empty the current page of duplicates, we don't need to
- * touch the parent page.
- */
- if (prev_pgno != PGNO_INVALID || (h != NULL && pgno == h->pgno))
- goto done;
+ if (NUM_ENT(h) == 1 &&
+ prev_pgno == PGNO_INVALID && next_pgno == PGNO_INVALID)
+ normal = 1;
+ else {
+ normal = 0;
- /*
- * Release any page we're holding and the lock on the deleted
- * page.
- */
+ /* Delete the duplicate. */
+ if ((ret = __db_drem(dbp, &h, indx, __bam_free)) != 0)
+ goto err;
+
+ /*
+ * 2a: h != NULL, h->pgno == pgno
+ * 2b: We don't reach this clause, as the above test
+ * was true.
+ * 2c: h == NULL, prev_pgno != PGNO_INVALID
+ * 2d: h != NULL, next_pgno != PGNO_INVALID
+ *
+ * Test for 2a and 2c: if we didn't empty the current
+ * page or there was a previous page of duplicates, we
+ * don't need to touch the parent page.
+ */
+ if ((h != NULL && pgno == h->pgno) ||
+ prev_pgno != PGNO_INVALID)
+ goto done;
+ }
+
+ /* Release any page we're holding and its lock. */
if (local) {
if (h != NULL)
(void)memp_fput(dbp->mpf, h, 0);
@@ -1519,37 +1533,33 @@ __bam_c_physdel(dbp, cp, h)
}
local = 1;
- /*
- * If we deleted the last duplicate, we can fall out and do a
- * normal btree delete in the context of the parent page. If
- * not, we have to update the parent's page.
- */
+ /* Switch to the parent page's entry. */
indx = cp->indx;
- if (next_pgno != PGNO_INVALID) {
- /*
- * Copy, delete, update and re-insert the parent page's
- * entry.
- */
- bo = *GET_BOVERFLOW(h, indx);
- (void)__db_ditem(dbp, h, indx, BOVERFLOW_SIZE);
- bo.pgno = next_pgno;
- memset(&dbt, 0, sizeof(dbt));
- dbt.data = &bo;
- dbt.size = BOVERFLOW_SIZE;
- (void)__db_pitem(dbp,
- h, indx, BOVERFLOW_SIZE, &dbt, NULL);
-
- /* Discard the parent page. */
- (void)memp_fput(dbp->mpf, h, 0);
- (void)__BT_TLPUT(dbp, lock);
- local = 0;
+ if (normal)
+ goto btd;
- goto done;
- }
+ /*
+ * Copy, delete, update, add-back the parent page's data entry.
+ *
+ * XXX
+ * This may be a performance/logging problem. We should add a
+ * log message which simply logs/updates a random set of bytes
+ * on a page, and use it instead of doing a delete/add pair.
+ */
+ indx += O_INDX;
+ bo = *GET_BOVERFLOW(h, indx);
+ (void)__db_ditem(dbp, h, indx, BOVERFLOW_SIZE);
+ bo.pgno = next_pgno;
+ memset(&dbt, 0, sizeof(dbt));
+ dbt.data = &bo;
+ dbt.size = BOVERFLOW_SIZE;
+ (void)__db_pitem(dbp, h, indx, BOVERFLOW_SIZE, &dbt, NULL);
+ (void)memp_fset(dbp->mpf, h, DB_MPOOL_DIRTY);
+ goto done;
}
/* Otherwise, do a normal btree delete. */
- if ((ret = __bam_ditem(dbp, h, indx)) != 0)
+btd: if ((ret = __bam_ditem(dbp, h, indx)) != 0)
goto err;
if ((ret = __bam_ditem(dbp, h, indx)) != 0)
goto err;
@@ -1584,7 +1594,7 @@ __bam_c_physdel(dbp, cp, h)
}
ret = __bam_dpage(dbp, &dbt);
- free(dbt.data);
+ __db_free(dbt.data);
}
err: