Add bttest unlink page command

To enable testing of recursive btree traversal, add an unlink page
command to the bttest program (used for debugging the libdb2 btree
back end).  This new bttest command can unlink a specified page
number, or it can search for and unlink a page that has both a left
and a right sibling.  (The user can specify whether to find an
internal page or a leaf page.)

This unlinking makes the page inaccessible to conventional sequential
traversal, simulating some btree corruption that has been seen in the
field.

ticket: 8476

diff --git a/src/plugins/kdb/db2/libdb2/btree/bt_delete.c b/src/plugins/kdb/db2/libdb2/btree/bt_delete.c
index 4133aa3f0b1d30a03728ea15d9acd660a2cd6e7b..b2f3a752867ae37b733dd4a171cf02d088742a96 100644 (file)
--- a/src/plugins/kdb/db2/libdb2/btree/bt_delete.c
+++ b/src/plugins/kdb/db2/libdb2/btree/bt_delete.c
@@ -50,7 +50,6 @@ static char sccsid[] = "@(#)bt_delete.c       8.13 (Berkeley) 7/28/94";
 static int __bt_bdelete __P((BTREE *, const DBT *));
 static int __bt_curdel __P((BTREE *, const DBT *, PAGE *, u_int));
 static int __bt_pdelete __P((BTREE *, PAGE *));
-static int __bt_relink __P((BTREE *, PAGE *));
 static int __bt_stkacq __P((BTREE *, PAGE **, CURSOR *));
 
 /*
@@ -634,7 +633,7 @@ dup2:                               c->pg.pgno = e.page->pgno;
  *     t:      tree
  *     h:      page to be deleted
  */
-static int
+int
 __bt_relink(t, h)
        BTREE *t;
        PAGE *h;

diff --git a/src/plugins/kdb/db2/libdb2/btree/extern.h b/src/plugins/kdb/db2/libdb2/btree/extern.h
index c29b084644d335496bd8152e06990895f0eebd4d..9f4082aff26787db880efb2353a1aea424c8fd62 100644 (file)
--- a/src/plugins/kdb/db2/libdb2/btree/extern.h
+++ b/src/plugins/kdb/db2/libdb2/btree/extern.h
@@ -62,6 +62,7 @@
 #define __bt_dpage     __kdb2_bt_dpage
 #define __bt_dump      __kdb2_bt_dump
 #define __bt_stat      __kdb2_bt_stat
+#define __bt_relink    __kdb2_bt_relink
 
 int     __bt_close __P((DB *));
 int     __bt_cmp __P((BTREE *, const DBT *, EPG *));
@@ -90,12 +91,11 @@ int  __ovfl_delete __P((BTREE *, void *));
 int     __ovfl_get __P((BTREE *, void *, size_t *, void **, size_t *));
 int     __ovfl_put __P((BTREE *, const DBT *, db_pgno_t *));
 
-#ifdef DEBUG
 int     __bt_dnpage __P((DB *, db_pgno_t));
 int     __bt_dpage __P((DB *, PAGE *));
 int     __bt_dmpage __P((PAGE *));
 int     __bt_dump __P((DB *));
-#endif
-#ifdef STATISTICS
+
 int     __bt_stat __P((DB *));
-#endif
+
+int     __bt_relink __P((BTREE *, PAGE *));

diff --git a/src/plugins/kdb/db2/libdb2/libdb.exports b/src/plugins/kdb/db2/libdb2/libdb.exports
index 7828da114606f9a342b79b604dab14f4290b0ba1..0c1689187ff1fd9dd03c067dc965e2cdee3db6fa 100644 (file)
--- a/src/plugins/kdb/db2/libdb2/libdb.exports
+++ b/src/plugins/kdb/db2/libdb2/libdb.exports
@@ -24,6 +24,7 @@ __kdb2_bt_open
 __kdb2_bt_pgin
 __kdb2_bt_pgout
 __kdb2_bt_put
+__kdb2_bt_relink
 __kdb2_bt_ret
 __kdb2_bt_search
 __kdb2_bt_seq

diff --git a/src/plugins/kdb/db2/libdb2/test/btree.tests/main.c b/src/plugins/kdb/db2/libdb2/test/btree.tests/main.c
index 33de7a2ff84b3be7321ebccbdab9908991d6dbdc..8281d0e77a4353022a115c085befd81a57351953 100644 (file)
--- a/src/plugins/kdb/db2/libdb2/test/btree.tests/main.c
+++ b/src/plugins/kdb/db2/libdb2/test/btree.tests/main.c
@@ -33,6 +33,35 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+/*
+ * Copyright (C) 2016 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in
+ *   the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
 
 #if defined(LIBC_SCCS) && !defined(lint)
 static char sccsid[] = "@(#)main.c     8.1 (Berkeley) 6/4/93";
@@ -98,6 +127,7 @@ void rnext   __P((DB *, char **));
 void rprev     __P((DB *, char **));
 void usage     __P((void));
 void user      __P((DB *));
+void unlinkpg  __P((DB *, char **));
 
 cmd_table commands[] = {
        "?",    0, 0, help, "help", NULL,
@@ -138,6 +168,8 @@ cmd_table commands[] = {
 #ifdef DEBUG
        "sh",   1, 0, show, "show page", "dump a page",
 #endif
+       "u",    1, 0, unlinkpg, "unlink pgno|internal|leaf", "unlink a page",
+
        { NULL },
 };
 
@@ -883,3 +915,59 @@ usage()
            progname);
        exit (1);
 }
+
+/* Find a candidate page to unlink. */
+static PAGE *
+candidatepg(BTREE *t, char *arg)
+{
+       PAGE *h = NULL;
+       db_pgno_t pg;
+       u_int32_t sflags;
+
+       if (arg[0] == 'i')
+               sflags = P_BINTERNAL | P_RINTERNAL;
+       if (arg[0] == 'l')
+               sflags = P_BLEAF | P_RLEAF;
+       for (pg = P_ROOT; pg < t->bt_mp->npages;
+            mpool_put(t->bt_mp, h, 0), pg++) {
+               if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
+                       return h;
+               /* Look for a nonempty page of the correct
+                * type that has both left and right siblings. */
+               if (h->prevpg == P_INVALID || h->nextpg == P_INVALID)
+                       continue;
+               if ((h->flags & sflags) && NEXTINDEX(h) != 0)
+                       break;
+       }
+       if (pg == t->bt_mp->npages)
+               h = NULL;
+       return h;
+}
+
+void
+unlinkpg(DB *db, char **argv)
+{
+       BTREE *t = db->internal;
+       PAGE *h = NULL;
+       db_pgno_t pg;
+
+       pg = atoi(argv[1]);
+       if (pg == 0)
+               h = candidatepg(t, argv[1]);
+       else
+               h = mpool_get(t->bt_mp, pg, 0);
+
+       if (h == NULL) {
+               fprintf(stderr, "unable to find appropriate page to unlink\n");
+               return;
+       }
+       printf("chain %d <- %d -> %d\n", h->prevpg, h->pgno, h->nextpg);
+       if (__bt_relink(t, h) != 0) {
+               perror("unlinkpg");
+               goto cleanup;
+       }
+       h->prevpg = P_INVALID;
+       h->nextpg = P_INVALID;
+cleanup:
+       mpool_put(t->bt_mp, h, MPOOL_DIRTY);
+}