cluster/tier: Adding compaction option for metadata databases

Problem: As metadata in the database fills up, querying the database
take a long time. As a result, tier migration slows down.  To
counteract this, we added a way to enable the compaction methods of
the underlying database. The goal is to reduce the size of the
underlying file by eliminating database fragmentation.

NOTE: There is currently a bug where sometimes a brick will
attempt to activate compaction. This happens even compaction is already
turned on.

The cause is narrowed down to the compact_mode_switch flipping its value.

Changes: libglusterfs/src/gfdb - Added a gfdb function to compact the
underlying database, compact_db() This is a no-op if the database has
no such option.

- Added a compaction function for SQLite3 that does the following

1) Changes the auto_vacuum pragma of the database
2) Compacts the database according to the type of compaction requested

- Compaction type can be changed by changing the macro
  GF_SQL_COMPACT_DEF to one of the 4 compaction types in
  gfdb_sqlite3.h

  It is currently set to GF_SQL_COMPACT_INCR, or incremental
  vacuuming.

xlators/cluster/dht/src - Added the following command-line option to
enable SQLite3 compaction.

gluster volume set <vol-name> tier-compact <off|on>

- Added the following command-line option to change the frequency the
  hot and cold tier are ordered to compact.

gluster volume set <vol-name> tier-hot-compact-frequency <int>
gluster volume set <vol-name> tier-cold-compact-frequency <int>

- tier daemon periodically sends the (new)
  GFDB_IPC_CTR_SET_COMPACT_PRAGMA IPC to the CTR xlator. The IPC
  triggers compaction of the database.

  The inputs are both gf_boolean_t.

  IPC Input:

  compact_active: Is compaction currently on for the db.
  compact_mode_switched: Did we flip the compaction switch recently?

  IPC Output:

  0 if the compaction succeeds.
  Non-zero otherwise.

xlators/features/changetimerecorder/src/ - When the CTR gets the
compaction IPC, it launches a thread that will perform the
compaction. The IPC ends after the thread is launched. To avoid extra
allocations, the parameters are passed using static variables.

Change-Id: I5e1433becb9eeff2afe8dcb4a5798977bf5ba0dd
Signed-off-by: Diogenes Nunez <dnunez@redhat.com>
Reviewed-on: http://review.gluster.org/15031
Reviewed-by: Milind Changire <mchangir@redhat.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 22 insertions, 1 deletions

diff --git a/libglusterfs/src/libglusterfs-messages.h b/libglusterfs/src/libglusterfs-messages.h
index d2ad44e470e..29196929eb3 100644
--- a/libglusterfs/src/libglusterfs-messages.h
+++ b/libglusterfs/src/libglusterfs-messages.h
@@ -36,7 +36,9 @@
  */
 
 #define GLFS_LG_BASE            GLFS_MSGID_COMP_LIBGLUSTERFS
-#define GLFS_LG_NUM_MESSAGES    207
+
+#define GLFS_LG_NUM_MESSAGES    209
+
 #define GLFS_LG_MSGID_END       (GLFS_LG_BASE + GLFS_LG_NUM_MESSAGES + 1)
 /* Messaged with message IDs */
 #define glfs_msg_start_lg GLFS_LG_BASE, "Invalid: Start of messages"
@@ -1762,6 +1764,7 @@
  * @recommendedaction
  *
  */
+
 #define LG_MSG_INVALID_INODE_LIST                         (GLFS_LG_BASE + 207)
 
 /*!
@@ -1770,6 +1773,24 @@
  * @recommendedaction
  *
  */
+
+#define LG_MSG_COMPACT_FAILED                            (GLFS_LG_BASE + 208)
+
+/*!
+ * @messageid
+ * @diagnosis
+ * @recommendedaction
+ *
+ */
+
+#define LG_MSG_COMPACT_STATUS                            (GLFS_LG_BASE + 209)
+
+/*!
+ * @messageid
+ * @diagnosis
+ * @recommendedaction
+ *
+ */
 /*------------*/
 
 #define glfs_msg_end_lg GLFS_LG_MSGID_END, "Invalid: End of messages"