Replication lag monitoring in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to check the replication offset on a Redis slave.

Redis

redis-cli info replication | grep [1]

Drag options to blanks, or click blank then click option'

Aconnected_slaves

Bmaster_repl_offset

Cslave_repl_offset

Drole

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'master_repl_offset' which shows master's offset, not slave's.

Using 'connected_slaves' which shows count, not offset.

The slave_repl_offset shows the replication offset on the slave, which helps monitor replication lag.

2fill in blank

medium

Complete the command to check the replication lag in seconds using Redis latency info.

Redis

redis-cli latency latest | grep [1]

Drag options to blanks, or click blank then click option'

Areplication-delay

Bcommand-stats

Cslowlog

Dlatency

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'command-stats' which shows command statistics, not replication lag.

Using 'slowlog' which shows slow commands, unrelated to replication lag.

The replication-delay latency event shows the delay in seconds between master and slave.

3fill in blank

hard

Fix the error in the command to monitor replication lag by comparing master and slave offsets.

Redis

master_offset=$(redis-cli info replication | grep [1] | cut -d':' -f2)
slave_offset=$(redis-cli info replication | grep slave_repl_offset | cut -d':' -f2)
lag=$((master_offset - slave_offset))
echo $lag

Drag options to blanks, or click blank then click option'

Amaster_repl_offset

Bslave_repl_offset

Cconnected_slaves

Drole

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'slave_repl_offset' for master offset causes incorrect lag calculation.

Using 'connected_slaves' which is unrelated to offsets.

The master offset must be fetched using master_repl_offset to calculate lag correctly.

4fill in blank

hard

Fill both blanks to create a Redis command that shows replication lag in bytes and seconds.

Redis

redis-cli info replication | grep [1]
redis-cli latency latest | grep [2]

Drag options to blanks, or click blank then click option'

Amaster_repl_offset

Breplication-delay

Cslave_repl_offset

Dcommand-stats

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'slave_repl_offset' instead of 'master_repl_offset' for byte lag.

Using 'command-stats' which is unrelated to replication lag.

The master_repl_offset shows lag in bytes, and replication-delay shows lag in seconds.

5fill in blank

hard

Fill all three blanks to create a script snippet that calculates replication lag in bytes and prints a warning if lag exceeds threshold.

Redis

master_offset=$(redis-cli info replication | grep [1] | cut -d':' -f2)
slave_offset=$(redis-cli info replication | grep [2] | cut -d':' -f2)
lag=$((master_offset - slave_offset))
if [ $lag -gt [3] ]; then
  echo "Warning: Replication lag is high: $lag bytes"
fi

Drag options to blanks, or click blank then click option'

Amaster_repl_offset

Bslave_repl_offset

C1000

Dconnected_slaves

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up master and slave offset keys.

Using a non-numeric value for the threshold.

The script compares master_repl_offset and slave_repl_offset to find lag in bytes and warns if lag is greater than 1000 bytes.