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, 6 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/tier.h b/xlators/cluster/dht/src/tier.h
index 0807608fda2..ffb04173bd5 100644
--- a/xlators/cluster/dht/src/tier.h
+++ b/xlators/cluster/dht/src/tier.h
@@ -54,6 +54,7 @@ typedef struct _query_cbk_args {
         /* This is write */
         int                     query_fd;
         int                     is_promotion;
+        int                     is_compaction;
         /* This is for read */
         tier_qfile_array_t       *qfile_array;
 } query_cbk_args_t;
@@ -82,6 +83,8 @@ typedef struct _dm_thread_args {
         int                     freq_time;
         int                     return_value;
         int                     is_promotion;
+        int                     is_compaction;
+        gf_boolean_t            is_hot_tier;
 } migration_args_t;
 
 typedef enum tier_watermark_op_ {
@@ -93,12 +96,15 @@ typedef enum tier_watermark_op_ {
 
 #define DEFAULT_PROMOTE_FREQ_SEC       120
 #define DEFAULT_DEMOTE_FREQ_SEC        120
+#define DEFAULT_HOT_COMPACT_FREQ_SEC   604800
+#define DEFAULT_COLD_COMPACT_FREQ_SEC  604800
 #define DEFAULT_DEMOTE_DEGRADED        10
 #define DEFAULT_WRITE_FREQ_SEC         0
 #define DEFAULT_READ_FREQ_SEC          0
 #define DEFAULT_WM_LOW                 75
 #define DEFAULT_WM_HI                  90
 #define DEFAULT_TIER_MODE              TIER_MODE_TEST
+#define DEFAULT_COMP_MODE              _gf_true
 #define DEFAULT_TIER_MAX_MIGRATE_MB    1000
 #define DEFAULT_TIER_MAX_MIGRATE_FILES 5000