MINOR: cache: Add a max-secondary-entries cache option
This new option allows to tune the maximum number of simultaneous
entries with the same primary key in the cache (secondary entries).
When we try to store a response in the cache and there are already
max-secondary-entries living entries in the cache, the storage will
fail (but the response will still be sent to the client).
It defaults to 10 and does not have a maximum number.
diff --git a/src/cache.c b/src/cache.c
index 60946de..a833c04 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -49,6 +49,7 @@
unsigned int maxage; /* max-age */
unsigned int maxblocks;
unsigned int maxobjsz; /* max-object-size (in bytes) */
+ unsigned int max_secondary_entries; /* maximum number of secondary entries with the same primary hash */
uint8_t vary_processing_enabled; /* boolean : manage Vary header (disabled by default) */
char id[33]; /* cache name */
};
@@ -104,7 +105,7 @@
struct shared_block *first_block;
};
-#define SECONDARY_ENTRY_MAX_COUNT 10
+#define DEFAULT_MAX_SECONDARY_ENTRY 10
struct cache_entry {
unsigned int complete; /* An entry won't be valid until complete is not null. */
@@ -276,7 +277,7 @@
entry_count = entry->secondary_entries_count;
last_clear_ts = entry->last_clear_ts;
- if (entry_count >= SECONDARY_ENTRY_MAX_COUNT) {
+ if (entry_count >= cache->max_secondary_entries) {
/* Some entries of the duplicate list might be expired so
* we will iterate over all the items in order to free some
* space. In order to avoid going over the same list too
@@ -291,7 +292,7 @@
}
entry_count = clear_expired_duplicates(&prev);
- if (entry_count >= SECONDARY_ENTRY_MAX_COUNT) {
+ if (entry_count >= cache->max_secondary_entries) {
/* Still too many entries for this primary key, delete
* the newly inserted one. */
entry = container_of(prev, struct cache_entry, eb);
@@ -1800,6 +1801,7 @@
tmp_cache_config->maxage = 60;
tmp_cache_config->maxblocks = 0;
tmp_cache_config->maxobjsz = 0;
+ tmp_cache_config->max_secondary_entries = DEFAULT_MAX_SECONDARY_ENTRY;
}
} else if (strcmp(args[0], "total-max-size") == 0) {
unsigned long int maxsize;
@@ -1877,6 +1879,29 @@
}
tmp_cache_config->vary_processing_enabled = atoi(args[1]);
+ } else if (strcmp(args[0], "max-secondary-entries") == 0) {
+ unsigned int max_sec_entries;
+ char *err;
+
+ if (alertif_too_many_args(1, file, linenum, args, &err_code)) {
+ err_code |= ERR_ABORT;
+ goto out;
+ }
+
+ if (!*args[1]) {
+ ha_warning("parsing [%s:%d]: '%s' expects a strictly positive number.\n",
+ file, linenum, args[0]);
+ err_code |= ERR_WARN;
+ }
+
+ max_sec_entries = strtoul(args[1], &err, 10);
+ if (err == args[1] || *err != '\0' || max_sec_entries == 0) {
+ ha_warning("parsing [%s:%d]: max-secondary-entries wrong value '%s'\n",
+ file, linenum, args[1]);
+ err_code |= ERR_ABORT;
+ goto out;
+ }
+ tmp_cache_config->max_secondary_entries = max_sec_entries;
}
else if (*args[0] != 0) {
ha_alert("parsing [%s:%d] : unknown keyword '%s' in 'cache' section\n", file, linenum, args[0]);