18 Jul 2018
Spring Cacheable Multiple Parameter
Background
This is a weird issue from spring @Cacheable annotation implement, eventually didn’t figure out the root cause, however, I got the the solution for it –!
The environment is SpringBoot 1.1.9 (which use spring-core 4.1.3) and Redis, we use SpringBoot function to interact with the Redis.
Issue
We have a simple cache like below:
@Override
@Cacheable(value = "PerfData")
public List<User> getPerfDataForUserId(Long peerUserId, Long targetUserId) throws Exception {
return perfDAO.getPerfDataForUserId(peerUserId, targetUserId);
}
@Override
@CacheEvict(value = "PerfData", allEntries = true)
public void clearAllCachePerfData() {
LOGGER.info("Clear Cache for all PerfData ");
}
@Override
@CacheEvict(value = "PerfData")
public void clearCachePerfDataForUserId(Long peerUserId, Long targetUserId) {
LOGGER.info("Clear Cache PerfData ");
}
The issue is if we passed the parameter which are different value such as (peerUserId: 111L, targetUserId: 222L), we are able to get correct value from cache. However, if we passed the same value such as (peerUserId: 111L, targetUserId: 111L), then next time when the value got change, we still got old data from cache.
Troubleshot
After lots of time spent, I identified it was a cache issue because of the Spring @Cacheable annotation. Here is the step to reproduce:
1.flush all the Redis cache
2.read data from application for (peerUserId: 111L, targetUserId: 111L)
3.check the Redis cache, the new record has added
$ /usr/local/bin/redis-cli -h 10.10.10.10 -p 6389 keys *PerfData*
# find cache
"PerfData:\xac\xed\x00\x05sr\x00/org.springframework.cache.interceptor.SimpleKeyL\nW\x03km\x93\xd8\x02\x00\x02I\x00\bhashCode[\x00\x06paramst\x00\x13[Ljava/lang/Object;xp\x00\x12z\xe1ur\x00\x13[Ljava.lang.Object;\x90\xceX\x9f\x10s)l\x02\x00\x00xp\x00\x00\x00\x02sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x00\x00\x00\x00\x93\xb9q\x00~\x00\a"
4.call the clearAndWarm cache API which evict then cache the keys again for (peerUserId: 111L, targetUserId: 111L)
5.check the Redis cache again, old record still there, and a new record was added
$ /usr/local/bin/redis-cli -h 10.10.10.10 -p 6389 keys *PerfData*
# find cache
"PerfData:\xac\xed\x00\x05sr\x00/org.springframework.cache.interceptor.SimpleKeyL\nW\x03km\x93\xd8\x02\x00\x02I\x00\bhashCode[\x00\x06paramst\x00\x13[Ljava/lang/Object;xp\x00\x12z\xe1ur\x00\x13[Ljava.lang.Object;\x90\xceX\x9f\x10s)l\x02\x00\x00xp\x00\x00\x00\x02sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x00\x00\x00\x00\x93\xb9sq\x00~\x00\x05\x00\x00\x00\x00\x00\x00\x93\xb9"
6.the application still got the old value
Thus, the issue is because we have two cache value, the getPerfDataForUserId(111L, 111L) original was reading some key with “~\x00\a”, looks like it means empty. I tried decode the string with HEX, Unicode and UTF-8, unfortunately I was not able to decode it, the @Cacheable created weird key for some reason.
Test
I realize there was issue regarding @Cacheable before Spring 4.0, it has collapse, however, we are using Spring-core 4.1.3, should be find. To verify, tried below test cases:
public static void main(String[] args) {
SimpleKeyGenerator skg = new SimpleKeyGenerator();
Object m1 = skg.generateKey(new Object[] { 109, 434 });
Object m2 = skg.generateKey(new Object[] { 110, 403 });
System.out.println(m1.hashCode() +"," +(m2.hashCode()));//same
System.out.println(m1.equals(m2)); //false
Long l1 = new Long(37817);
Long l2 = new Long(37817);
Long l3 = new Long(37817);
Object key1 = skg.generateKey(l1, l2);
Object key2 = skg.generateKey(l1, l3);
System.out.println(key1.hashCode() + "," + key2.hashCode());
System.out.println(key1.equals(key2)); //true
DefaultKeyGenerator dkg = new DefaultKeyGenerator();
Object n1 = dkg.generateKey(new Object[] { 109, 403 });
Object n2 = dkg.generateKey(new Object[] { 403, 109 });
System.out.println(n1.hashCode() +"," +(n2.hashCode())); //same
System.out.println(dkg.generate(null, null, 1, 0)); // 16368
System.out.println(dkg.generate(null, null, 0, 31)); // 16368
Object key3 = dkg.generate(null, null, l1, l2);
Object key4 = dkg.generate(null, null, l1, l3);
System.out.println(key3.hashCode() +","+ key4.hashCode());
System.out.println(key3.equals(key4)); //true
}
Tried the default Key Generate “SimpleKeyGenerator” if didn’t specify the Key generate in annotation, it can generate the key correctly.
Solution
Didn’t find the cause why it create the wrong cache key, but It came out with the solution, we can customize the key to match the Redis, did below change:
@Override
@Cacheable(value = "PerfData", key = "{#peerUserId.longValue() + '_'+ #targetUserId.longValue()}")
public List<User> getPerfDataForUserId(Long peerUserId, Long targetUserId) throws Exception {
return perfDAO.getPerfDataForUserId(peerUserId, targetUserId);
}
@Override
@CacheEvict(value = "PerfData", allEntries = true)
public void clearAllCachePerfData() {
LOGGER.info("Clear Cache for all PerfData ");
}
@Override
@CacheEvict(value = "PerfData", key = "{#peerUserId.longValue() + '_'+ #targetUserId.longValue()}")
public void clearCachePerfDataForUserId(Long peerUserId, Long targetUserId) {
LOGGER.info("Clear Cache PerfData ");
}
After this change, the cache read and evict will work fine, it will use only one unique key for the case (peerUserId: 111L, targetUserId: 111L)
$ /usr/local/bin/redis-cli -h 10.10.10.10 -p 6389 keys *PerfData*
# find cache
"PerfData:\xac\xed\x00\x05sr\x00\x13java.util.ArrayListx\x81\xd2\x1d\x99\xc7a\x9d\x03\x00\x01I\x00\x04sizexp\x00\x00\x00\x01w\x04\x00\x00\x00\x01t\x00\n111_111x"
Reference
@Cacheable key on multiple method arguments
Til next time,
at 00:00
