mdbx-tools: добавление опций `-d` и `-p` для `mdbx_copy`.

src/man1/mdbx_copy.1

@@ -14,6 +14,10 @@ mdbx_copy \- MDBX environment copy tool
 [\c
 .BR \-c ]
 [\c
+.BR \-d ]
+[\c
+.BR \-p ]
+[\c
 .BR \-n ]
 .B src_path
 [\c
@@ -45,6 +49,22 @@ or unused pages will be omitted from the copy. This option will
 slow down the backup process as it is more CPU-intensive.
 Currently it fails if the environment has suffered a page leak.
 .TP
+.BR \-d
+Alters geometry to enforce the copy to be a dynamic size DB,
+which could be growth and shrink by reasonable steps on the fly.
+.TP
+.BR \-p
+Use read transaction parking/ousting during copying MVCC-snapshot.
+This allows the writing transaction to oust the read
+transaction used to copy the database if copying takes so long
+that it will interfere with the recycling old MVCC snapshots
+and may lead to an overflow of the database.
+However, if the reading transaction is ousted the copy will
+be aborted until successful completion. Thus, this option
+allows copy the database without interfering with write
+transactions and a threat of database overflow, but at the cost
+that copying will be aborted to prevent such conditions.
+.TP
 .BR \-u
 Warms up the DB before copying via notifying OS kernel of subsequent access to the database pages.
 .TP

src/tools/copy.c

@@ -39,10 +39,13 @@ static void signal_handler(int sig) {
 static void usage(const char *prog) {
   fprintf(
       stderr,
-      "usage: %s [-V] [-q] [-c] [-u|U] src_path [dest_path]\n"
+      "usage: %s [-V] [-q] [-c] [-d] [-p] [-u|U] src_path [dest_path]\n"
       "  -V\t\tprint version and exit\n"
       "  -q\t\tbe quiet\n"
       "  -c\t\tenable compactification (skip unused pages)\n"
+      "  -d\t\tenforce copy to be a dynamic size DB\n"
+      "  -p\t\tusing transaction parking/ousting during copying MVCC-snapshot\n"
+      "    \t\tto avoid stopping recycling and overflowing the DB\n"
       "  -u\t\twarmup database before copying\n"
       "  -U\t\twarmup and try lock database pages in memory before copying\n"
       "  src_path\tsource database\n"
@@ -66,6 +69,10 @@ int main(int argc, char *argv[]) {
       flags |= MDBX_NOSUBDIR;
     else if (argv[1][1] == 'c' && argv[1][2] == '\0')
       cpflags |= MDBX_CP_COMPACT;
+    else if (argv[1][1] == 'd' && argv[1][2] == '\0')
+      cpflags |= MDBX_CP_FORCE_DYNAMIC_SIZE;
+    else if (argv[1][1] == 'p' && argv[1][2] == '\0')
+      cpflags |= MDBX_CP_THROTTLE_MVCC;
     else if (argv[1][1] == 'q' && argv[1][2] == '\0')
       quiet = true;
     else if (argv[1][1] == 'u' && argv[1][2] == '\0')