row0ins.c, dict0dict.c, dict0dict.h, srv0srv.c:

  Let SHOW INNODB STATUS print detailed info of the latest unique key violation, note that REPLACE and INSERT IGNORE mask the error from the user

innobase/dict/dict0dict.c

@@ -185,10 +185,12 @@ dict_foreign_free(
 /*==============*/
 	dict_foreign_t*	foreign);	/* in, own: foreign key struct */
 
-/* Buffer for storing detailed information about the latest foreig  key
-error */
+/* Buffers for storing detailed information about the latest foreign key
+and unique key errors */
 char*	dict_foreign_err_buf		= NULL;
-mutex_t	dict_foreign_err_mutex; 	/* mutex protecting the buffer */
+char*	dict_unique_err_buf		= NULL;
+mutex_t	dict_foreign_err_mutex; 	/* mutex protecting the foreign
+					and unique error buffers */
 	
 	
 /************************************************************************
@@ -582,6 +584,8 @@ dict_init(void)
 
 	dict_foreign_err_buf = mem_alloc(DICT_FOREIGN_ERR_BUF_LEN);
 	dict_foreign_err_buf[0] = '\0';
+	dict_unique_err_buf = mem_alloc(DICT_FOREIGN_ERR_BUF_LEN);
+	dict_unique_err_buf[0] = '\0';
 	mutex_create(&dict_foreign_err_mutex);
 	mutex_set_level(&dict_foreign_err_mutex, SYNC_ANY_LATCH);
 }

innobase/include/dict0dict.h

@@ -839,10 +839,11 @@ dict_mutex_exit_for_mysql(void);
 /* The following len must be at least 10000 bytes! */
 #define DICT_FOREIGN_ERR_BUF_LEN	10000
 
-/* Buffer for storing detailed information about the latest foreig  key
-error */
+/* Buffers for storing detailed information about the latest foreign key
+and unique key errors */
 extern char*	dict_foreign_err_buf;
-extern mutex_t	dict_foreign_err_mutex; /* mutex protecting the buffer */
+extern char*	dict_unique_err_buf;
+extern mutex_t	dict_foreign_err_mutex; /* mutex protecting the buffers */
 
 extern dict_sys_t*	dict_sys;	/* the dictionary system */
 extern rw_lock_t	dict_operation_lock;

innobase/row/row0ins.c

@@ -1263,6 +1263,48 @@ row_ins_check_foreign_constraints(
 	return(DB_SUCCESS);
 }
 
+/*************************************************************************
+Reports a UNIQUE key error to dict_unique_err_buf so that SHOW INNODB
+STATUS can print it. */
+static
+void
+row_ins_unique_report_err(
+/*======================*/
+	que_thr_t*	thr,	/* in: query thread */
+	rec_t*		rec,	/* in: a record in the index */
+	dtuple_t*	entry,	/* in: index entry to insert in the index */
+	dict_index_t*	index)	/* in: index */
+{
+	char*	buf	= dict_unique_err_buf;
+
+	/* The foreign err mutex protects also dict_unique_err_buf */
+
+	mutex_enter(&dict_foreign_err_mutex);
+
+	ut_sprintf_timestamp(buf);
+	sprintf(buf + strlen(buf), " Transaction:\n");
+	trx_print(buf + strlen(buf), thr_get_trx(thr));			
+
+	sprintf(buf + strlen(buf),
+"Unique key constraint fails for table %.500s.\n", index->table_name);
+	sprintf(buf + strlen(buf),
+"Trying to add in index %.500s (%lu fields unique) tuple:\n", index->name,
+	  				dict_index_get_n_unique(index));
+		
+	dtuple_sprintf(buf + strlen(buf), 1000, entry);
+
+	sprintf(buf + strlen(buf),
+"\nBut there is already a record:\n");
+
+	rec_sprintf(buf + strlen(buf), 1000, rec);
+
+	sprintf(buf + strlen(buf), "\n");
+
+	ut_a(strlen(buf) < DICT_FOREIGN_ERR_BUF_LEN);
+
+	mutex_exit(&dict_foreign_err_mutex);
+}
+
 /*******************************************************************
 Checks if a unique key violation to rec would occur at the index entry
 insert. */
@@ -1393,10 +1435,8 @@ row_ins_scan_sec_index_for_duplicate(
 
 		if (cmp == 0) {
 			if (row_ins_dupl_error_with_rec(rec, entry, index)) {
-				/* printf("Duplicate key in index %s\n",
-				     				index->name);
-				dtuple_print(entry); */
-
+				row_ins_unique_report_err(thr, rec, entry,
+								   index);
 				err = DB_DUPLICATE_KEY;
 
 				thr_get_trx(thr)->error_info = index;
@@ -1491,7 +1531,8 @@ row_ins_duplicate_error_in_clust(
 			if (row_ins_dupl_error_with_rec(rec, entry,
 							cursor->index)) {
 				trx->error_info = cursor->index;
-				
+				row_ins_unique_report_err(thr, rec, entry,
+							  cursor->index);
 				return(DB_DUPLICATE_KEY);
 			}
 		}
@@ -1515,6 +1556,8 @@ row_ins_duplicate_error_in_clust(
 							cursor->index)) {
 				trx->error_info = cursor->index;
 
+				row_ins_unique_report_err(thr, rec, entry,
+							  cursor->index);
 				return(DB_DUPLICATE_KEY);
 			}
 		}

innobase/srv/srv0srv.c

@@ -162,7 +162,7 @@ in the buffer pool to all database pages in the buffer pool smaller than
 the following number. But it is not guaranteed that the value stays below
 that during a time of heavy update/insert activity. */
 
-ulint	srv_max_buf_pool_modified_pct	= 100;
+ulint	srv_max_buf_pool_modified_pct	= 90;
 
 /* If the following is != 0 we do not allow inserts etc. This protects
 the user from forgetting the innodb_force_recovery keyword to my.cnf */
@@ -2366,6 +2366,19 @@ srv_sprintf_innodb_monitor(
 
 	ut_a(buf < buf_end + 1500);
 
+	if (*dict_unique_err_buf != '\0') {
+		buf += sprintf(buf,
+"---------------------------------------------------------------\n"
+"LATEST UNIQUE KEY ERROR (is masked in REPLACE or INSERT IGNORE)\n"
+"---------------------------------------------------------------\n");
+
+		if (buf_end - buf > 6000) {
+			buf+= sprintf(buf, "%.4000s", dict_unique_err_buf);
+		}
+	}	
+
+	ut_a(buf < buf_end + 1500);
+
 	lock_print_info(buf, buf_end);
 	buf = buf + strlen(buf);