RBPS Usage Instructions ​

Overview ​

rbps (Recovery Buffer Pool Server, RBP Server) is the page cache server of RBP; when RBP is enabled, the database can use pages stored in RBPS during the recovery process, thereby reducing the recovery time in node failure recovery scenarios.

RBPS is positioned as follows:

• A recovery acceleration component, not a data file, log file, or backup tool.
• It does not change the way users use SQL. Once enabled, page writes and reads are automatically completed by the database.
• If RBPS is unavailable, the RBP window does not meet the recovery conditions, or the recovery security check fails, the database will fall back to conventional recovery.
• In a CMS deployment, it is recommended that the rbps resource be managed primarily through CMS; rbps_ctl is mainly used for local auxiliary checks and fault location.

Installation and Configuration ​

After a normal oGRAC installation, RBPS-related files are located in the database installation directory:

rbps_ctl reads $OGDB_DATA/cfg/rbps.conf by default, and a configuration file can also be specified using -c.

Configuring rbps.conf ​

Each node where RBPS is deployed needs to configure rbps.conf. Common configurations are as follows:

HOST=0.0.0.0
PORT=2611

ADMIN_HOST=127.0.0.1
ADMIN_PORT=2711

LOG_FILE=$OGDB_HOME/../../log/rbps/rbps.log
PID_FILE=$OGDB_HOME/run/rbps.pid

MAX_CACHE_PAGES=3000000
CAPACITY_EVICT_ON_WRITE=false
READ_END_MODE=async
READ_PHASE_TIMEOUT=3

VERBOSE=false
TIMING_DIAG=false

Configuration item description:

Normal Deployment Process ​

1. Preparing the RBPS Server Configuration ​

On each RBPS node, verify that HOST, PORT, and LOG_FILE in rbps.conf are correct. If CMS is used for management, confirm that $OGDB_HOME/bin/rbps_contrl.sh and $OGDB_HOME/bin/rbps_ctl are executable.

2. Confirming Database-Side Configuration ​

On each database node, complete the database-side configuration as described in RBP Accelerated Recovery Reference, and ensure that the database-side connection address and port match the RBPS server listening configuration. The database GUC parameter descriptions are not elaborated here.

3. Starting RBPS via CMS ​

During CMS deployment, the installation process attempts to pre-register the rbps resource. After RBP is enabled on the database side, RBPS can be started and checked using CMS:

su -s /bin/bash ograc
source ~/.bashrc

cms res -list
cms res -start rbps
cms stat -res rbps

Stop RBPS:

cms res -stop rbps

If RBP is disabled on the database side, CMS considers the rbps resource as disabled:

• cms res -list and cms stat will hide rbps.
• cms res -start rbps will fail with a message indicating that the resource is disabled.

4. Restarting the Database Instance ​

After modifying the restart-related parameters according to the database-side configuration reference, the database instance must be restarted. Once the instance is started, the database loads the RBP configuration and connects to RBPS. Under normal circumstances, RBP connection or heartbeat-related information can be observed in the logs.

Verifying That Components Are Normal ​

It is recommended to check in the following order:

# 1. Check whether CMS has registered and manages the rbps resource.
cms res -list

# 2. Check whether rbps is online from the CMS perspective. If STAT shows ONLINE, CMS considers the RBPS resource online.
cms stat -res rbps 

# 3. Check whether the local process and management port are normal.
rbps_ctl status     # "rbps is running" indicates that the local RBPS process has started.
rbps_ctl stats      # "OK" indicates that the local RBPS management port is accessible.

rbps_ctl Auxiliary Command Reference ​

rbps_ctl is not the preferred start/stop entry point under CMS deployment. For routine management, cms res -start rbps, cms res -stop rbps, and cms stat -res rbps should be used first. The commands in this section are used when it is necessary to locally verify the process, check the management port, view cache statistics, or inspect the recovery window.

start ​

Starts RBPS locally. In a CMS deployment, it is recommended to use cms res -start rbps for routine startup.

Example output upon successful startup:

rbps started: pid=12345 listen=0.0.0.0:2611 admin=127.0.0.1:2711 conf=/data/ograc/cfg/rbps.conf log=/data/ograc/log/rbps/rbps.log

Example output if the service is already running:

rbps is already running: pid=12345 conf=/data/ograc/cfg/rbps.conf

status ​

Queries the RBPS process status.

Example output when running:

rbps is running: pid=12345 listen=0.0.0.0:2611 admin=127.0.0.1:2711 conf=/data/ograc/cfg/rbps.conf log=/data/ograc/log/rbps/rbps.log

Example output when not running:

rbps is not running

stop and stop_force ​

stop stops RBPS normally on the local node. stop_force first attempts a normal stop; and if the process does not exit within a short period, it forcibly terminates the process. In a CMS deployment, it is recommended to use cms res -stop rbps for routine stopping. stop_force is recommended only when CMS fails to stop the resource normally or during local troubleshooting.

Output example:

rbps stopped: pid=12345
rbps force stopped: pid=12345

restart ​

Restarts RBPS locally, which is equivalent to executing stop first and then start.

stats ​

Queries brief RBPS statistics.

Output example:

OK cache_total=100 pending_total=0 max_cache_pages=0 capacity_evict_on_write=0

Field description:

window ​

Queries the current RBP recovery window.

Output example:

WINDOW_BEGIN
cache_pages=100
pending_pages=0
max_cache_pages=0
capacity_evict_on_write=0
max_lsn=123456789
begin=rst=0 asn=1 blk=100 lfn=1000 lsn=123000000
rcy=rst=0 asn=1 blk=200 lfn=2000 lsn=123400000
lrp=rst=0 asn=1 blk=250 lfn=2500 lsn=123456789
evict_in_progress=0
purge_stable=1
empty_reason=
WINDOW_END

Field description:

read_phase ​

Queries the status of the read recovery phase.

Output example:

READ_PHASE_BEGIN
active=0
ending=0
elapsed_ms=0
idle_ms=0
inflight_reads=0
timeout_s=3
dropped_page_writes=0
timeout_warned=0
READ_PHASE_END

Field description:

force_read_end ​

Forcibly releases residual READ_PHASE. Use this only when the recovery read phase is confirmed to be abnormally left over.

Output example:

OK active_before=1 ending_before=0 cleared=1 elapsed_ms=5000 dropped_page_writes=10 detached_pages=20

Field description:

exists ​

Queries whether a specified page is in the RBPS cache. The page format is <file>-<page>, and <file>_<page> or <file>/<page> can also be used.

Output example:

FOUND file=1 page=100 lsn=123456789 pcn=10 cache_total=20

Output example when not found:

NOT_FOUND file=1 page=100 cache_total=20

dump ​

Outputs detailed diagnostic information for a specified page, primarily used for issue locating. If the page does not exist, the output is consistent with the NOT_FOUND result of exists.

Output example:

rbps_ctl dump 12-14529
DUMP_BEGIN
file=12
page=14529
qid=1
pending=1
cache_total=59485
writer_inst=0
writer_seq=75433224
page_lsn=75433224
page_pcn=10
page_checksum=0x0000
trunc_rst=0
trunc_asn=1
trunc_blk=89775149
trunc_lfn=69383
trunc_lsn=2199023255552
lrp_rst=0
lrp_asn=1
lrp_blk=89776459
lrp_lfn=69410
lrp_lsn=2199023255552
reset=rst=0 asn=1 blk=89030039 lfn=50761 lsn=2199023255552
frontier=rst=0 asn=1 blk=91513030 lfn=102072 lsn=2199023255552
trunc_hex=010000002ddc590500001c3c040000000000000000020000
lrp_hex=010000004be159050000883c040000000000000000020000
page_header_hex=c13800000c00110200000000ff03010008057f04000000000a000000000000000c086c00003e01010170ab07540a000002b0a009540a0000090000000200ff3fc23800000c00501ca01f5003140014000200000002e01530a38b000000000000
page_tail_hex=90042c03c001600002e01530a38b00000c026a030100000001144a0615001000017076b77b0a0000050000000200000001c01e0417000000000000000a000000
DUMP_END

Field description:

query ​

Sends a query command directly to the management port. Commonly used commands include:

rbps_ctl query STATS
rbps_ctl query WINDOW
rbps_ctl query READ_PHASE
rbps_ctl query FORCE_READ_END

The output fields are the same as those of stats, window, read_phase, and force_read_end, respectively.

Troubleshooting ​

rbps_ctl Reports That the Configuration File Cannot Be Found ​

Verify that the environment variables have been loaded, or specify the configuration file using -c:

source ~/.bashrc
rbps_ctl status -c $OGDB_DATA/cfg/rbps.conf

CMS Fails to Start the rbps Resource ​

First, follow RBP Accelerated Recovery Reference to confirm that the database has completed the configuration and restarted the instance, and then execute:

cms res -start rbps
cms stat -res rbps

stats or window Returns No Result ​

Prioritize checking the following:

• Whether cms stat -res rbps shows the resource as ONLINE.
• If CMS displays an abnormal status, use rbps_ctl status to confirm whether the local process shows rbps is running.
• Whether ADMIN_HOST and ADMIN_PORT in rbps.conf are correct.
• Whether the current user has loaded environment variables such as $OGDB_HOME and $OGDB_DATA.

RBP Not Used During Recovery Phase ​

Check in the following order:

• Whether the database has completed configuration according to RBP Accelerated Recovery Reference and restarted the instance.
• Whether the RBPS service address and port match the connection configuration on the database side, and whether the service port is accessible from the database node.
• Whether rbps_ctl window has a valid window.
• Whether the database logs contain information such as connection failures, mismatched address configurations, or fallback to conventional recovery.

Even if RBP is enabled, the database will automatically fall back to conventional recovery if the current recovery window does not meet the usage conditions.

READ_PHASE Not Released for a Long Time ​

First, query:

rbps_ctl read_phase

If it is confirmed that the recovery read phase has been abnormally left over, execute:

rbps_ctl force_read_end

Cache Page Limit Reached ​

If MAX_CACHE_PAGES is set and CAPACITY_EVICT_ON_WRITE=false, new pages will be rejected for writing once the cache is full. You may increase MAX_CACHE_PAGES according to the environment capacity, or configure the following:

CAPACITY_EVICT_ON_WRITE=true

RBPS must be restarted after rbps.conf is modified.