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, 18 insertions, 3 deletions

diff --git a/libglusterfs/src/gfdb/gfdb_sqlite3.h b/libglusterfs/src/gfdb/gfdb_sqlite3.h
index 9d0d996a322..4d70a60e431 100644
--- a/libglusterfs/src/gfdb/gfdb_sqlite3.h
+++ b/libglusterfs/src/gfdb/gfdb_sqlite3.h
@@ -73,8 +73,7 @@ do {\
 
 #define GF_SQL_AV_NONE  "none"
 #define GF_SQL_AV_FULL  "full"
-#define GF_SQL_AV_INCR  "incr"
-
+#define GF_SQL_AV_INCR  "incremental"
 
 #define GF_SQL_SYNC_OFF         "off"
 #define GF_SQL_SYNC_NORMAL      "normal"
@@ -87,7 +86,12 @@ do {\
 #define GF_SQL_JM_WAL           "wal"
 #define GF_SQL_JM_OFF           "off"
 
+#define GF_SQL_COMPACT_NONE   0
+#define GF_SQL_COMPACT_FULL   1
+#define GF_SQL_COMPACT_INCR   2
+#define GF_SQL_COMPACT_MANUAL 3
 
+#define GF_SQL_COMPACT_DEF    GF_SQL_COMPACT_INCR
 typedef enum gf_sql_auto_vacuum {
         gf_sql_av_none = 0,
         gf_sql_av_full,
@@ -319,7 +323,18 @@ int gf_sqlite3_pragma (void *db_conn, char *pragma_key, char **pragma_value);
 int
 gf_sqlite3_set_pragma (void *db_conn, char *pragma_key, char *pragma_value);
 
-
+/* Function to vacuum of sqlite db
+ * Input:
+ * void *db_conn                      : Sqlite connection
+ * gf_boolean_t compact_active        : Is compaction on?
+ * gf_boolean_t compact_mode_switched : Did we just flip the compaction swtich?
+ * Return:
+ *      On success return 0
+ *      On failure return -1
+ * */
+int
+gf_sqlite3_vacuum (void *db_conn, gf_boolean_t compact_active,
+                   gf_boolean_t compact_mode_switched);
 
 void gf_sqlite3_fill_db_operations (gfdb_db_operations_t  *gfdb_db_ops);