This moves selection of the initial RRA row into the rrd_open.c API

[rrdtool.git] / src / rrd_open.c

diff --git a/src/rrd_open.c b/src/rrd_open.c
index f262413..6b2d6ac 100644 (file)
--- a/src/rrd_open.c
+++ b/src/rrd_open.c
@@ -54,6 +54,10 @@
 #endif
 #endif
 
+long int  rra_random_row(
+    rra_def_t *);
+
+
 /* Open a database file, return its header and an open filehandle,
  * positioned to the first cdp in the first rra.
  * In the error path of rrd_open, only rrd_free(&rrd) has to be called
@@ -79,13 +83,14 @@ rrd_file_t *rrd_open(
     rrd_file_t *rrd_file = NULL;
     off_t     newfile_size = 0;
 
-    if (rdwr & RRD_CREAT) {
+    if ((rdwr & RRD_CREAT) && (rdwr & RRD_CREAT_SETSIZE)) {
         /* yes bad inline signaling alert, we are using the
            floatcookie to pass the size in ... only used in resize */
         newfile_size = (off_t) rrd->stat_head->float_cookie;
         free(rrd->stat_head);
     }
-    rrd_init(rrd);
+    if(!(rdwr & RRD_CREAT))
+        rrd_init(rrd);
     rrd_file = malloc(sizeof(rrd_file_t));
     if (rrd_file == NULL) {
         rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
@@ -170,7 +175,13 @@ rrd_file_t *rrd_open(
            }
         }
 */
+
 #ifdef HAVE_MMAP
+    if(rrd_file->file_len == 0 && (rdwr & RRD_CREAT))
+    {
+        rrd_file->file_start = NULL;
+        goto out_done;
+    }
     data = mmap(0, rrd_file->file_len, mm_prot, mm_flags,
                 rrd_file->fd, offset);
 
@@ -535,10 +546,36 @@ ssize_t rrd_write(
     size_t count)
 {
 #ifdef HAVE_MMAP
+    /* These flags are used if creating a new RRD */
+    int       mm_prot = PROT_READ | PROT_WRITE, mm_flags = MAP_SHARED;
+    int old_size = rrd_file->file_len;
+    int new_size = rrd_file->file_len;
     if (count == 0)
         return 0;
     if (buf == NULL)
         return -1;      /* EINVAL */
+    
+    if((rrd_file->pos + count) > old_size)
+    {
+        new_size = rrd_file->pos + count; 
+        rrd_file->file_len = new_size;
+        lseek(rrd_file->fd, new_size - 1, SEEK_SET);
+        write(rrd_file->fd, "\0", 1);   /* poke */
+        lseek(rrd_file->fd, 0, SEEK_SET);
+        if(rrd_file->file_start == NULL)
+        {
+            rrd_file->file_start = mmap(0, new_size, mm_prot, mm_flags,
+                rrd_file->fd, 0);
+        }
+        else
+            rrd_file->file_start = mremap(rrd_file->file_start, old_size, new_size, MREMAP_MAYMOVE); 
+
+        if (rrd_file->file_start == MAP_FAILED) {
+            rrd_set_error("m(re)maping file : %s", 
+                      rrd_strerror(errno));
+            return -1;
+        }
+    }
     memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */
@@ -615,3 +652,46 @@ void rrd_freemem(
 {
     free(mem);
 }
+
+/*
+ * rra_update informs us about the RRAs being updated
+ * The low level storage API may use this information for
+ * aligning RRAs within stripes, or other performance enhancements
+ */
+void rrd_notify_row(
+    rrd_file_t *rrd_file,
+    int rra_idx,
+    unsigned long rra_row,
+    time_t rra_time)
+{
+}
+
+/*
+ * This function is called when creating a new RRD
+ * The storage implementation can use this opportunity to select
+ * a sensible starting row within the file.
+ * The default implementation is random, to ensure that all RRAs
+ * don't change to a new disk block at the same time
+ */
+unsigned long rrd_select_initial_row(
+    rrd_file_t *rrd_file,
+    int rra_idx,
+    rra_def_t *rra
+    )
+{
+    return rra_random_row(rra);
+}
+
+static int rand_init = 0;
+
+long int rra_random_row(
+    rra_def_t *rra)
+{
+    if (!rand_init) {
+        srandom((unsigned int) time(NULL) + (unsigned int) getpid());
+        rand_init++;
+    }
+
+    return random() % rra->row_cnt;
+}
+