Import wiredtiger: 543111d3d8737ada1b741b3a25a201feb2ed13a3 from branch mongodb-4.0

ref: 48bf8dae7c..543111d3d8
for: 4.0.13

WT-4502       Assertion checking hazard pointers on page discard is too strong
WT-4658       Apply Clang Format
WT-4792       Add stat to track pages queued for eviction after LRU sorting
WT-4840       WT_CURSOR.modify must require explicit, snapshot-isolation transaction
WT-4869       Stop adding cache pressure when eviction is falling behind
WT-4881       Soften the restrictions on re-entering reconciliation
WT-4882       Improve checkpoint performance when there are large metadata pages
WT-4892       Improve statistics about forced eviction
WT-4893       Fix a race between internal page child-page eviction checks and cursors in the tree
WT-4895       Fix debug eviction mode so it chooses skew more randomly
WT-4898       Don't allow the eviction server to reconcile if it's busy
WT-4920       Add statistics tracking when eviction server is waiting for page transitions
WT-4957       Revert part of a change about when pages are queued for urgent eviction
WT-5050       Assertion failure during urgent eviction of metadata page

1 files changed, 323 insertions, 350 deletions

diff --git a/src/third_party/wiredtiger/src/schema/schema_plan.c b/src/third_party/wiredtiger/src/schema/schema_plan.c
index f7efa49b0a3..67b6567632c 100644
--- a/src/third_party/wiredtiger/src/schema/schema_plan.c
+++ b/src/third_party/wiredtiger/src/schema/schema_plan.c
@@ -10,400 +10,373 @@
 
 /*
  * __find_next_col --
- *	Find the next column to use for a plan.
+ *     Find the next column to use for a plan.
  */
 static int
-__find_next_col(WT_SESSION_IMPL *session, WT_TABLE *table,
-    WT_CONFIG_ITEM *colname, u_int *cgnump, u_int *colnump, char *coltype)
+__find_next_col(WT_SESSION_IMPL *session, WT_TABLE *table, WT_CONFIG_ITEM *colname, u_int *cgnump,
+  u_int *colnump, char *coltype)
 {
-	WT_COLGROUP *colgroup;
-	WT_CONFIG conf;
-	WT_CONFIG_ITEM cval, k, v;
-	WT_DECL_RET;
-	u_int cg, col, foundcg, foundcol, matchcg, matchcol;
-	bool getnext;
-
-	foundcg = foundcol = UINT_MAX;
-	matchcg = *cgnump;
-	matchcol = (*coltype == WT_PROJ_KEY) ?
-	    *colnump : *colnump + table->nkey_columns;
-
-	getnext = true;
-	for (colgroup = NULL, cg = 0; cg < WT_COLGROUPS(table); cg++) {
-		colgroup = table->cgroups[cg];
-
-		/*
-		 * If there is only one column group, we just scan through all
-		 * of the columns.  For tables with multiple column groups, we
-		 * look at the key columns once, then go through the value
-		 * columns for each group.
-		 */
-		if (cg == 0) {
-			cval = table->colconf;
-			col = 0;
-		} else {
-cgcols:			cval = colgroup->colconf;
-			col = table->nkey_columns;
-		}
-		__wt_config_subinit(session, &conf, &cval);
-		for (; (ret = __wt_config_next(&conf, &k, &v)) == 0; col++) {
-			if (k.len == colname->len &&
-			    strncmp(colname->str, k.str, k.len) == 0) {
-				if (getnext) {
-					foundcg = cg;
-					foundcol = col;
-				}
-				getnext = cg == matchcg && col == matchcol;
-			}
-			if (cg == 0 && table->ncolgroups > 0 &&
-			    col == table->nkey_columns - 1)
-				goto cgcols;
-		}
-		WT_RET_TEST(ret != WT_NOTFOUND, ret);
-
-		colgroup = NULL;
-	}
-
-	if (foundcg == UINT_MAX)
-		return (WT_NOTFOUND);
-
-	*cgnump = foundcg;
-	if (foundcol < table->nkey_columns) {
-		*coltype = WT_PROJ_KEY;
-		*colnump = foundcol;
-	} else {
-		*coltype = WT_PROJ_VALUE;
-		*colnump = foundcol - table->nkey_columns;
-	}
-	return (0);
+    WT_COLGROUP *colgroup;
+    WT_CONFIG conf;
+    WT_CONFIG_ITEM cval, k, v;
+    WT_DECL_RET;
+    u_int cg, col, foundcg, foundcol, matchcg, matchcol;
+    bool getnext;
+
+    foundcg = foundcol = UINT_MAX;
+    matchcg = *cgnump;
+    matchcol = (*coltype == WT_PROJ_KEY) ? *colnump : *colnump + table->nkey_columns;
+
+    getnext = true;
+    for (colgroup = NULL, cg = 0; cg < WT_COLGROUPS(table); cg++) {
+        colgroup = table->cgroups[cg];
+
+        /*
+         * If there is only one column group, we just scan through all of the columns. For tables
+         * with multiple column groups, we look at the key columns once, then go through the value
+         * columns for each group.
+         */
+        if (cg == 0) {
+            cval = table->colconf;
+            col = 0;
+        } else {
+cgcols:
+            cval = colgroup->colconf;
+            col = table->nkey_columns;
+        }
+        __wt_config_subinit(session, &conf, &cval);
+        for (; (ret = __wt_config_next(&conf, &k, &v)) == 0; col++) {
+            if (k.len == colname->len && strncmp(colname->str, k.str, k.len) == 0) {
+                if (getnext) {
+                    foundcg = cg;
+                    foundcol = col;
+                }
+                getnext = cg == matchcg && col == matchcol;
+            }
+            if (cg == 0 && table->ncolgroups > 0 && col == table->nkey_columns - 1)
+                goto cgcols;
+        }
+        WT_RET_TEST(ret != WT_NOTFOUND, ret);
+
+        colgroup = NULL;
+    }
+
+    if (foundcg == UINT_MAX)
+        return (WT_NOTFOUND);
+
+    *cgnump = foundcg;
+    if (foundcol < table->nkey_columns) {
+        *coltype = WT_PROJ_KEY;
+        *colnump = foundcol;
+    } else {
+        *coltype = WT_PROJ_VALUE;
+        *colnump = foundcol - table->nkey_columns;
+    }
+    return (0);
 }
 
 /*
  * __wt_schema_colcheck --
- *	Check that a list of columns matches a (key,value) format pair.
+ *     Check that a list of columns matches a (key,value) format pair.
  */
 int
-__wt_schema_colcheck(WT_SESSION_IMPL *session,
-    const char *key_format, const char *value_format, WT_CONFIG_ITEM *colconf,
-    u_int *kcolsp, u_int *vcolsp)
+__wt_schema_colcheck(WT_SESSION_IMPL *session, const char *key_format, const char *value_format,
+  WT_CONFIG_ITEM *colconf, u_int *kcolsp, u_int *vcolsp)
 {
-	WT_CONFIG conf;
-	WT_CONFIG_ITEM k, v;
-	WT_DECL_PACK_VALUE(pv);
-	WT_DECL_RET;
-	WT_PACK pack;
-	u_int kcols, ncols, vcols;
-
-	WT_RET(__pack_init(session, &pack, key_format));
-	for (kcols = 0; (ret = __pack_next(&pack, &pv)) == 0; kcols++)
-		;
-	WT_RET_NOTFOUND_OK(ret);
-
-	WT_RET(__pack_init(session, &pack, value_format));
-	for (vcols = 0; (ret = __pack_next(&pack, &pv)) == 0; vcols++)
-		;
-	WT_RET_TEST(ret != WT_NOTFOUND, ret);
-
-	/* Walk through the named columns. */
-	__wt_config_subinit(session, &conf, colconf);
-	for (ncols = 0; (ret = __wt_config_next(&conf, &k, &v)) == 0; ncols++)
-		;
-	WT_RET_TEST(ret != WT_NOTFOUND, ret);
-
-	if (ncols != 0 && ncols != kcols + vcols)
-		WT_RET_MSG(session, EINVAL, "Number of columns in '%.*s' "
-		    "does not match key format '%s' plus value format '%s'",
-		    (int)colconf->len, colconf->str, key_format, value_format);
-
-	if (kcolsp != NULL)
-		*kcolsp = kcols;
-	if (vcolsp != NULL)
-		*vcolsp = vcols;
-
-	return (0);
+    WT_CONFIG conf;
+    WT_CONFIG_ITEM k, v;
+    WT_DECL_PACK_VALUE(pv);
+    WT_DECL_RET;
+    WT_PACK pack;
+    u_int kcols, ncols, vcols;
+
+    WT_RET(__pack_init(session, &pack, key_format));
+    for (kcols = 0; (ret = __pack_next(&pack, &pv)) == 0; kcols++)
+        ;
+    WT_RET_NOTFOUND_OK(ret);
+
+    WT_RET(__pack_init(session, &pack, value_format));
+    for (vcols = 0; (ret = __pack_next(&pack, &pv)) == 0; vcols++)
+        ;
+    WT_RET_TEST(ret != WT_NOTFOUND, ret);
+
+    /* Walk through the named columns. */
+    __wt_config_subinit(session, &conf, colconf);
+    for (ncols = 0; (ret = __wt_config_next(&conf, &k, &v)) == 0; ncols++)
+        ;
+    WT_RET_TEST(ret != WT_NOTFOUND, ret);
+
+    if (ncols != 0 && ncols != kcols + vcols)
+        WT_RET_MSG(session, EINVAL,
+          "Number of columns in '%.*s' "
+          "does not match key format '%s' plus value format '%s'",
+          (int)colconf->len, colconf->str, key_format, value_format);
+
+    if (kcolsp != NULL)
+        *kcolsp = kcols;
+    if (vcolsp != NULL)
+        *vcolsp = vcols;
+
+    return (0);
 }
 
 /*
  * __wt_table_check --
- *	Make sure all columns appear in a column group.
+ *     Make sure all columns appear in a column group.
  */
 int
 __wt_table_check(WT_SESSION_IMPL *session, WT_TABLE *table)
 {
-	WT_CONFIG conf;
-	WT_CONFIG_ITEM k, v;
-	WT_DECL_RET;
-	u_int cg, col, i;
-	char coltype;
-
-	if (table->is_simple)
-		return (0);
-
-	/* Walk through the columns. */
-	__wt_config_subinit(session, &conf, &table->colconf);
-
-	/* Skip over the key columns. */
-	for (i = 0; i < table->nkey_columns; i++)
-		WT_RET(__wt_config_next(&conf, &k, &v));
-	cg = col = 0;
-	coltype = 0;
-	while ((ret = __wt_config_next(&conf, &k, &v)) == 0) {
-		if (__find_next_col(
-		    session, table, &k, &cg, &col, &coltype) != 0)
-			WT_RET_MSG(session, EINVAL,
-			    "Column '%.*s' in '%s' does not appear in a "
-			    "column group",
-			    (int)k.len, k.str, table->iface.name);
-		/*
-		 * Column groups can't store key columns in their value:
-		 * __wt_struct_reformat should have already detected this case.
-		 */
-		WT_ASSERT(session, coltype == WT_PROJ_VALUE);
-
-	}
-	WT_RET_TEST(ret != WT_NOTFOUND, ret);
-
-	return (0);
+    WT_CONFIG conf;
+    WT_CONFIG_ITEM k, v;
+    WT_DECL_RET;
+    u_int cg, col, i;
+    char coltype;
+
+    if (table->is_simple)
+        return (0);
+
+    /* Walk through the columns. */
+    __wt_config_subinit(session, &conf, &table->colconf);
+
+    /* Skip over the key columns. */
+    for (i = 0; i < table->nkey_columns; i++)
+        WT_RET(__wt_config_next(&conf, &k, &v));
+    cg = col = 0;
+    coltype = 0;
+    while ((ret = __wt_config_next(&conf, &k, &v)) == 0) {
+        if (__find_next_col(session, table, &k, &cg, &col, &coltype) != 0)
+            WT_RET_MSG(session, EINVAL,
+              "Column '%.*s' in '%s' does not appear in a "
+              "column group",
+              (int)k.len, k.str, table->iface.name);
+        /*
+         * Column groups can't store key columns in their value:
+         * __wt_struct_reformat should have already detected this case.
+         */
+        WT_ASSERT(session, coltype == WT_PROJ_VALUE);
+    }
+    WT_RET_TEST(ret != WT_NOTFOUND, ret);
+
+    return (0);
 }
 
 /*
  * __wt_struct_plan --
- *	Given a table cursor containing a complete table, build the "projection
- *	plan" to distribute the columns to dependent stores.  A string
- *	representing the plan will be appended to the plan buffer.
+ *     Given a table cursor containing a complete table, build the "projection plan" to distribute
+ *     the columns to dependent stores. A string representing the plan will be appended to the plan
+ *     buffer.
  */
 int
-__wt_struct_plan(WT_SESSION_IMPL *session, WT_TABLE *table,
-    const char *columns, size_t len, bool value_only, WT_ITEM *plan)
+__wt_struct_plan(WT_SESSION_IMPL *session, WT_TABLE *table, const char *columns, size_t len,
+  bool value_only, WT_ITEM *plan)
 {
-	WT_CONFIG conf;
-	WT_CONFIG_ITEM k, v;
-	WT_DECL_RET;
-	u_int cg, col, current_cg, current_col, i, start_cg, start_col;
-	char coltype, current_coltype;
-	bool have_it;
-
-	start_cg = start_col = UINT_MAX;	/* -Wuninitialized */
-
-	/* Work through the value columns by skipping over the key columns. */
-	__wt_config_initn(session, &conf, columns, len);
-	if (value_only)
-		for (i = 0; i < table->nkey_columns; i++)
-			WT_RET(__wt_config_next(&conf, &k, &v));
-
-	current_cg = cg = 0;
-	current_col = col = INT_MAX;
-	current_coltype = coltype = WT_PROJ_KEY; /* Keep lint quiet. */
-	for (i = 0; (ret = __wt_config_next(&conf, &k, &v)) == 0; i++) {
-		have_it = false;
-
-		while ((ret = __find_next_col(session, table,
-		    &k, &cg, &col, &coltype)) == 0 &&
-		    (!have_it || cg != start_cg || col != start_col)) {
-			/*
-			 * First we move to the column.  If that is in a
-			 * different column group to the last column we
-			 * accessed, or before the last column in the same
-			 * column group, or moving from the key to the value,
-			 * we need to switch column groups or rewind.
-			 */
-			if (current_cg != cg || current_col > col ||
-			    current_coltype != coltype) {
-				WT_ASSERT(session, !value_only ||
-				    coltype == WT_PROJ_VALUE);
-				WT_RET(__wt_buf_catfmt(
-				    session, plan, "%u%c", cg, coltype));
-
-				/*
-				 * Set the current column group and column
-				 * within the table.
-				 */
-				current_cg = cg;
-				current_col = 0;
-				current_coltype = coltype;
-			}
-			/* Now move to the column we want. */
-			if (current_col < col) {
-				if (col - current_col > 1)
-					WT_RET(__wt_buf_catfmt(session,
-					    plan, "%u", col - current_col));
-				WT_RET(__wt_buf_catfmt(session,
-				    plan, "%c", WT_PROJ_SKIP));
-			}
-			/*
-			 * Now copy the value in / out.  In the common case,
-			 * where each value is used in one column, we do a
-			 * "next" operation.  If the value is used again, we do
-			 * a "reuse" operation to avoid making another copy.
-			 */
-			if (!have_it) {
-				WT_RET(__wt_buf_catfmt(session,
-				    plan, "%c", WT_PROJ_NEXT));
-
-				start_cg = cg;
-				start_col = col;
-				have_it = true;
-			} else
-				WT_RET(__wt_buf_catfmt(session,
-				    plan, "%c", WT_PROJ_REUSE));
-			current_col = col + 1;
-		}
-		/*
-		 * We may fail to find a column if it is a custom extractor.
-		 * In that case, treat it as the first value column: we only
-		 * ever use such plans to extract the primary key from the
-		 * index.
-		 */
-		if (ret == WT_NOTFOUND)
-			WT_RET(__wt_buf_catfmt(session, plan,
-			    "0%c%c", WT_PROJ_VALUE, WT_PROJ_NEXT));
-	}
-	WT_RET_TEST(ret != WT_NOTFOUND, ret);
-
-	/* Special case empty plans. */
-	if (i == 0 && plan->size == 0)
-		WT_RET(__wt_buf_set(session, plan, "", 1));
-
-	return (0);
+    WT_CONFIG conf;
+    WT_CONFIG_ITEM k, v;
+    WT_DECL_RET;
+    u_int cg, col, current_cg, current_col, i, start_cg, start_col;
+    char coltype, current_coltype;
+    bool have_it;
+
+    start_cg = start_col = UINT_MAX; /* -Wuninitialized */
+
+    /* Work through the value columns by skipping over the key columns. */
+    __wt_config_initn(session, &conf, columns, len);
+    if (value_only)
+        for (i = 0; i < table->nkey_columns; i++)
+            WT_RET(__wt_config_next(&conf, &k, &v));
+
+    current_cg = cg = 0;
+    current_col = col = INT_MAX;
+    current_coltype = coltype = WT_PROJ_KEY; /* Keep lint quiet. */
+    for (i = 0; (ret = __wt_config_next(&conf, &k, &v)) == 0; i++) {
+        have_it = false;
+
+        while ((ret = __find_next_col(session, table, &k, &cg, &col, &coltype)) == 0 &&
+          (!have_it || cg != start_cg || col != start_col)) {
+            /*
+             * First we move to the column. If that is in a different column group to the last
+             * column we accessed, or before the last column in the same column group, or moving
+             * from the key to the value, we need to switch column groups or rewind.
+             */
+            if (current_cg != cg || current_col > col || current_coltype != coltype) {
+                WT_ASSERT(session, !value_only || coltype == WT_PROJ_VALUE);
+                WT_RET(__wt_buf_catfmt(session, plan, "%u%c", cg, coltype));
+
+                /*
+                 * Set the current column group and column within the table.
+                 */
+                current_cg = cg;
+                current_col = 0;
+                current_coltype = coltype;
+            }
+            /* Now move to the column we want. */
+            if (current_col < col) {
+                if (col - current_col > 1)
+                    WT_RET(__wt_buf_catfmt(session, plan, "%u", col - current_col));
+                WT_RET(__wt_buf_catfmt(session, plan, "%c", WT_PROJ_SKIP));
+            }
+            /*
+             * Now copy the value in / out.  In the common case,
+             * where each value is used in one column, we do a
+             * "next" operation.  If the value is used again, we do
+             * a "reuse" operation to avoid making another copy.
+             */
+            if (!have_it) {
+                WT_RET(__wt_buf_catfmt(session, plan, "%c", WT_PROJ_NEXT));
+
+                start_cg = cg;
+                start_col = col;
+                have_it = true;
+            } else
+                WT_RET(__wt_buf_catfmt(session, plan, "%c", WT_PROJ_REUSE));
+            current_col = col + 1;
+        }
+        /*
+         * We may fail to find a column if it is a custom extractor. In that case, treat it as the
+         * first value column: we only ever use such plans to extract the primary key from the
+         * index.
+         */
+        if (ret == WT_NOTFOUND)
+            WT_RET(__wt_buf_catfmt(session, plan, "0%c%c", WT_PROJ_VALUE, WT_PROJ_NEXT));
+    }
+    WT_RET_TEST(ret != WT_NOTFOUND, ret);
+
+    /* Special case empty plans. */
+    if (i == 0 && plan->size == 0)
+        WT_RET(__wt_buf_set(session, plan, "", 1));
+
+    return (0);
 }
 
 /*
  * __find_column_format --
- *	Find the format of the named column.
+ *     Find the format of the named column.
  */
 static int
-__find_column_format(WT_SESSION_IMPL *session, WT_TABLE *table,
-    WT_CONFIG_ITEM *colname, bool value_only, WT_PACK_VALUE *pv)
+__find_column_format(WT_SESSION_IMPL *session, WT_TABLE *table, WT_CONFIG_ITEM *colname,
+  bool value_only, WT_PACK_VALUE *pv)
 {
-	WT_CONFIG conf;
-	WT_CONFIG_ITEM k, v;
-	WT_DECL_RET;
-	WT_PACK pack;
-	bool inkey;
-
-	__wt_config_subinit(session, &conf, &table->colconf);
-	WT_RET(__pack_init(session, &pack, table->key_format));
-	inkey = true;
-
-	while ((ret = __wt_config_next(&conf, &k, &v)) == 0) {
-		if ((ret = __pack_next(&pack, pv)) == WT_NOTFOUND && inkey) {
-			ret = __pack_init(session, &pack, table->value_format);
-			if (ret == 0)
-				ret = __pack_next(&pack, pv);
-			inkey = false;
-		}
-		if (ret != 0)
-			return (ret);
-
-		if (k.len == colname->len &&
-		    strncmp(colname->str, k.str, k.len) == 0) {
-			if (value_only && inkey)
-				return (__wt_set_return(session, EINVAL));
-			return (0);
-		}
-	}
-
-	return (ret);
+    WT_CONFIG conf;
+    WT_CONFIG_ITEM k, v;
+    WT_DECL_RET;
+    WT_PACK pack;
+    bool inkey;
+
+    __wt_config_subinit(session, &conf, &table->colconf);
+    WT_RET(__pack_init(session, &pack, table->key_format));
+    inkey = true;
+
+    while ((ret = __wt_config_next(&conf, &k, &v)) == 0) {
+        if ((ret = __pack_next(&pack, pv)) == WT_NOTFOUND && inkey) {
+            ret = __pack_init(session, &pack, table->value_format);
+            if (ret == 0)
+                ret = __pack_next(&pack, pv);
+            inkey = false;
+        }
+        if (ret != 0)
+            return (ret);
+
+        if (k.len == colname->len && strncmp(colname->str, k.str, k.len) == 0) {
+            if (value_only && inkey)
+                return (__wt_set_return(session, EINVAL));
+            return (0);
+        }
+    }
+
+    return (ret);
 }
 
 /*
  * __wt_struct_reformat --
- *	Given a table and a list of columns (which could be values in a column
- *	group or index keys), calculate the resulting new format string.
- *	The result will be appended to the format buffer.
+ *     Given a table and a list of columns (which could be values in a column group or index keys),
+ *     calculate the resulting new format string. The result will be appended to the format buffer.
  */
 int
-__wt_struct_reformat(WT_SESSION_IMPL *session, WT_TABLE *table,
-    const char *columns, size_t len, const char *extra_cols, bool value_only,
-    WT_ITEM *format)
+__wt_struct_reformat(WT_SESSION_IMPL *session, WT_TABLE *table, const char *columns, size_t len,
+  const char *extra_cols, bool value_only, WT_ITEM *format)
 {
-	WT_CONFIG config;
-	WT_CONFIG_ITEM k, next_k, next_v;
-	WT_DECL_PACK_VALUE(pv);
-	WT_DECL_RET;
-	bool have_next;
-
-	__wt_config_initn(session, &config, columns, len);
-	/*
-	 * If an empty column list is specified, this will fail with
-	 * WT_NOTFOUND, that's okay.
-	 */
-	WT_RET_NOTFOUND_OK(ret = __wt_config_next(&config, &next_k, &next_v));
-	if (ret == WT_NOTFOUND) {
-		if (extra_cols != NULL) {
-			__wt_config_init(session, &config, extra_cols);
-			WT_RET(__wt_config_next(&config, &next_k, &next_v));
-			extra_cols = NULL;
-		} else if (format->size == 0) {
-			WT_RET(__wt_buf_set(session, format, "", 1));
-			return (0);
-		}
-	}
-	do {
-		k = next_k;
-		ret = __wt_config_next(&config, &next_k, &next_v);
-		if (ret != 0 && ret != WT_NOTFOUND)
-			return (ret);
-		have_next = ret == 0;
-
-		if (!have_next && extra_cols != NULL) {
-			__wt_config_init(session, &config, extra_cols);
-			WT_RET(__wt_config_next(&config, &next_k, &next_v));
-			have_next = true;
-			extra_cols = NULL;
-		}
-
-		if ((ret = __find_column_format(session,
-		    table, &k, value_only, &pv)) != 0) {
-			if (value_only && ret == EINVAL)
-				WT_RET_MSG(session, EINVAL,
-				    "A column group cannot store key column "
-				    "'%.*s' in its value", (int)k.len, k.str);
-			WT_RET_MSG(session, EINVAL,
-			    "Column '%.*s' not found", (int)k.len, k.str);
-		}
-
-		/*
-		 * Check whether we're moving an unsized WT_ITEM from the end
-		 * to the middle, or vice-versa.  This determines whether the
-		 * size needs to be prepended.  This is the only case where the
-		 * destination size can be larger than the source size.
-		 */
-		if (pv.type == 'u' && !pv.havesize && have_next)
-			pv.type = 'U';
-		else if (pv.type == 'U' && !have_next)
-			pv.type = 'u';
-
-		if (pv.havesize)
-			WT_RET(__wt_buf_catfmt(session,
-			    format, "%" PRIu32 "%c", pv.size, pv.type));
-		else
-			WT_RET(__wt_buf_catfmt(session, format, "%c", pv.type));
-	} while (have_next);
-
-	return (0);
+    WT_CONFIG config;
+    WT_CONFIG_ITEM k, next_k, next_v;
+    WT_DECL_PACK_VALUE(pv);
+    WT_DECL_RET;
+    bool have_next;
+
+    __wt_config_initn(session, &config, columns, len);
+    /*
+     * If an empty column list is specified, this will fail with WT_NOTFOUND, that's okay.
+     */
+    WT_RET_NOTFOUND_OK(ret = __wt_config_next(&config, &next_k, &next_v));
+    if (ret == WT_NOTFOUND) {
+        if (extra_cols != NULL) {
+            __wt_config_init(session, &config, extra_cols);
+            WT_RET(__wt_config_next(&config, &next_k, &next_v));
+            extra_cols = NULL;
+        } else if (format->size == 0) {
+            WT_RET(__wt_buf_set(session, format, "", 1));
+            return (0);
+        }
+    }
+    do {
+        k = next_k;
+        ret = __wt_config_next(&config, &next_k, &next_v);
+        if (ret != 0 && ret != WT_NOTFOUND)
+            return (ret);
+        have_next = ret == 0;
+
+        if (!have_next && extra_cols != NULL) {
+            __wt_config_init(session, &config, extra_cols);
+            WT_RET(__wt_config_next(&config, &next_k, &next_v));
+            have_next = true;
+            extra_cols = NULL;
+        }
+
+        if ((ret = __find_column_format(session, table, &k, value_only, &pv)) != 0) {
+            if (value_only && ret == EINVAL)
+                WT_RET_MSG(session, EINVAL,
+                  "A column group cannot store key column "
+                  "'%.*s' in its value",
+                  (int)k.len, k.str);
+            WT_RET_MSG(session, EINVAL, "Column '%.*s' not found", (int)k.len, k.str);
+        }
+
+        /*
+         * Check whether we're moving an unsized WT_ITEM from the end to the middle, or vice-versa.
+         * This determines whether the size needs to be prepended. This is the only case where the
+         * destination size can be larger than the source size.
+         */
+        if (pv.type == 'u' && !pv.havesize && have_next)
+            pv.type = 'U';
+        else if (pv.type == 'U' && !have_next)
+            pv.type = 'u';
+
+        if (pv.havesize)
+            WT_RET(__wt_buf_catfmt(session, format, "%" PRIu32 "%c", pv.size, pv.type));
+        else
+            WT_RET(__wt_buf_catfmt(session, format, "%c", pv.type));
+    } while (have_next);
+
+    return (0);
 }
 
 /*
  * __wt_struct_truncate --
- *	Return a packing string for the first N columns in a value.
+ *     Return a packing string for the first N columns in a value.
  */
 int
-__wt_struct_truncate(WT_SESSION_IMPL *session,
-    const char *input_fmt, u_int ncols, WT_ITEM *format)
+__wt_struct_truncate(WT_SESSION_IMPL *session, const char *input_fmt, u_int ncols, WT_ITEM *format)
 {
-	WT_DECL_PACK_VALUE(pv);
-	WT_PACK pack;
-
-	WT_RET(__pack_init(session, &pack, input_fmt));
-	while (ncols-- > 0) {
-		WT_RET(__pack_next(&pack, &pv));
-		if (pv.havesize)
-			WT_RET(__wt_buf_catfmt(session,
-			    format, "%" PRIu32 "%c", pv.size, pv.type));
-		else
-			WT_RET(__wt_buf_catfmt(session, format, "%c", pv.type));
-	}
-
-	return (0);
+    WT_DECL_PACK_VALUE(pv);
+    WT_PACK pack;
+
+    WT_RET(__pack_init(session, &pack, input_fmt));
+    while (ncols-- > 0) {
+        WT_RET(__pack_next(&pack, &pv));
+        if (pv.havesize)
+            WT_RET(__wt_buf_catfmt(session, format, "%" PRIu32 "%c", pv.size, pv.type));
+        else
+            WT_RET(__wt_buf_catfmt(session, format, "%c", pv.type));
+    }
+
+    return (0);
 }