Bug fix: during isc_merge operations, some pages weren't marked dirty

even though they should be. At this point the merge operation marks
a page dirty if the previous page changed at all. A better approach is
to mark it dirty if the last key written changed in previous page.

diff --git a/isamc/isamc.c b/isamc/isamc.c
index a5e1364..e276a07 100644 (file)
--- a/isamc/isamc.c
+++ b/isamc/isamc.c
@@ -4,7 +4,13 @@
  * Sebastian Hammer, Adam Dickmeiss
  *
  * $Log: isamc.c,v $
- * Revision 1.6  1996-11-08 11:15:29  adam
+ * Revision 1.7  1997-02-12 20:42:43  adam
+ * Bug fix: during isc_merge operations, some pages weren't marked dirty
+ * even though they should be. At this point the merge operation marks
+ * a page dirty if the previous page changed at all. A better approach is
+ * to mark it dirty if the last key written changed in previous page.
+ *
+ * Revision 1.6  1996/11/08 11:15:29  adam
  * Number of keys in chain are stored in first block and the function
  * to retrieve this information, isc_pp_num is implemented.
  *
@@ -171,8 +177,6 @@ int isc_close (ISAMC is)
 int isc_read_block (ISAMC is, int cat, int pos, char *dst)
 {
     ++(is->files[cat].no_reads);
-    if (is->method->debug > 2)
-        logf (LOG_LOG, "isc: read_block %d %d", cat, pos);
     return bf_read (is->files[cat].bf, pos, 0, 0, dst);
 }
 
@@ -325,6 +329,9 @@ ISAMC_PP isc_pp_open (ISAMC is, ISAMC_P ipos)
         assert (pp->next != pp->pos);
         pp->offset = src - pp->buf; 
         assert (pp->offset == ISAMC_BLOCK_OFFSET_1);
+        if (is->method->debug > 2)
+            logf (LOG_LOG, "isc: read_block size=%d %d %d",
+                 pp->size, pp->cat, pp->pos);
     }
     return pp;
 }
@@ -359,6 +366,9 @@ int isc_read_item (ISAMC_PP pp, char **dst)
             isc_release_block (is, pp->cat, pp->pos);
         (*is->method->code_item)(ISAMC_DECODE, pp->decodeClientData, dst, &src);
         pp->offset = src - pp->buf; 
+        if (is->method->debug > 2)
+            logf (LOG_LOG, "isc: read_block size=%d %d %d",
+                 pp->size, pp->cat, pp->pos);
         return 2;
     }
     (*is->method->code_item)(ISAMC_DECODE, pp->decodeClientData, dst, &src);

diff --git a/isamc/merge.c b/isamc/merge.c
index bb89fa1..c2578a8 100644 (file)
--- a/isamc/merge.c
+++ b/isamc/merge.c
@@ -4,7 +4,13 @@
  * Sebastian Hammer, Adam Dickmeiss
  *
  * $Log: merge.c,v $
- * Revision 1.4  1996-11-08 11:15:31  adam
+ * Revision 1.5  1997-02-12 20:42:43  adam
+ * Bug fix: during isc_merge operations, some pages weren't marked dirty
+ * even though they should be. At this point the merge operation marks
+ * a page dirty if the previous page changed at all. A better approach is
+ * to mark it dirty if the last key written changed in previous page.
+ *
+ * Revision 1.4  1996/11/08 11:15:31  adam
  * Number of keys in chain are stored in first block and the function
  * to retrieve this information, isc_pp_num is implemented.
  *
@@ -47,32 +53,40 @@ static void flush_blocks (ISAMC is, struct isc_merge_block *mb, int ptr,
         unsigned short ssize;
         char *src;
 
-        /* skip rest if not dirty */
-        if (!mb[i].dirty)
-        {
-            assert (mb[i].block);
-            if (!*firstpos)
-                *firstpos = mb[i].block;
-            if (is->method->debug > 2)
-                logf (LOG_LOG, "isc: skip block %d %d", cat, mb[i].block);
-            ++(is->files[cat].no_skip_writes);
-            continue;
-        }
         /* consider this block number */
-
         if (!mb[i].block) 
+        {
             mb[i].block = isc_alloc_block (is, cat);
+            mb[i].dirty = 1;
+        }
 
         /* consider next block pointer */
         if (last && i == ptr-1)
             mb[i+1].block = 0;
         else if (!mb[i+1].block)       
+        {
             mb[i+1].block = isc_alloc_block (is, cat);
+            mb[i+1].dirty = 1;
+            mb[i].dirty = 1;
+        }
 
-        /* write block */
         ssize = mb[i+1].offset - mb[i].offset;
         assert (ssize);
 
+        /* skip rest if not dirty */
+        if (!mb[i].dirty)
+        {
+            assert (mb[i].block);
+            if (!*firstpos)
+                *firstpos = mb[i].block;
+            if (is->method->debug > 2)
+                logf (LOG_LOG, "isc: skip ptr=%d size=%d %d %d",
+                     i, ssize, cat, mb[i].block);
+            ++(is->files[cat].no_skip_writes);
+            continue;
+        }
+        /* write block */
+
         if (!*firstpos)
         {
             *firstpos = mb[i].block;
@@ -82,16 +96,16 @@ static void flush_blocks (ISAMC is, struct isc_merge_block *mb, int ptr,
             memcpy (src+sizeof(int)+sizeof(ssize), numkeys,
                     sizeof(*numkeys));
             if (is->method->debug > 2)
-                logf (LOG_LOG, "isc: flush numk=%d size=%d nextpos=%d",
-                     *numkeys, (int) ssize, mb[i+1].block);
+                logf (LOG_LOG, "isc: flush ptr=%d numk=%d size=%d nextpos=%d",
+                     i, *numkeys, (int) ssize, mb[i+1].block);
         }
         else
         {
             src = r_buf + mb[i].offset - ISAMC_BLOCK_OFFSET_N;
             ssize += ISAMC_BLOCK_OFFSET_N;
             if (is->method->debug > 2)
-                logf (LOG_LOG, "isc: flush size=%d nextpos=%d",
-                     (int) ssize, mb[i+1].block);
+                logf (LOG_LOG, "isc: flush ptr=%d size=%d nextpos=%d",
+                     i, (int) ssize, mb[i+1].block);
         }
         memcpy (src, &mb[i+1].block, sizeof(int));
         memcpy (src+sizeof(int), &ssize, sizeof(ssize));
@@ -184,14 +198,19 @@ ISAMC_P isc_merge (ISAMC is, ISAMC_P ipos, ISAMC_I data)
                     if (mb[ptr].block)
                         isc_release_block (is, pp->cat, mb[ptr].block);
                     mb[ptr].block = pp->pos;
-                    mb[ptr].dirty = 0;
+                    mb[ptr].dirty = 2;
+                    if (ptr > 0)
+                        mb[ptr-1].dirty = 1;
                 }
                 else
                 {
                     /* indicate new boundary based on the original file */
                     mb[++ptr].block = pp->pos;
-                    mb[ptr].dirty = 0;
+                    mb[ptr].dirty = (mb[ptr-1].dirty > 1) ? 1 : 0;
                     mb[ptr].offset = r_offset;
+                    if (is->method->debug > 3)
+                        logf (LOG_LOG, "isc: bound ptr=%d,offset=%d",
+                            ptr, r_offset);
                     if (cat==is->max_cat && ptr >= is->method->max_blocks_mem)
                     {
                         /* We are dealing with block(s) of max size. Block(s)
@@ -247,7 +266,7 @@ ISAMC_P isc_merge (ISAMC is, ISAMC_P ipos, ISAMC_I data)
                 {
                     /* no! delete the item */
                     r_item = NULL;
-                    mb[ptr].dirty = 1;
+                    mb[ptr].dirty = 2;
                 }
             }
             else
@@ -279,7 +298,7 @@ ISAMC_P isc_merge (ISAMC is, ISAMC_P ipos, ISAMC_I data)
                 abort ();
             }
             memcpy (r_item, i_item, i_item_ptr - i_item);
-            mb[ptr].dirty = 1;
+            mb[ptr].dirty = 2;
             /* move i */
             i_item_ptr = i_item;
             i_more = (*data->read_item)(data->clientData, &i_item_ptr,