static mmc_t *mmc_consistent_find(mmc_consistent_state_t *state, unsigned int point) /* {{{ */
{
int lo = 0, hi = state->num_points - 1, mid;
while (1) {
/* point is outside interval or lo >= hi, wrap-around */
if (point <= state->points[lo].point || point > state->points[hi].point) {
return state->points[lo].server;
}
/* test middle point */
mid = lo + (hi - lo) / 2;
MMC_DEBUG(("mmc_consistent_find: lo %d, hi %d, mid %d, point %u, midpoint %u", lo, hi, mid, point, state->points[mid].point));
/* perfect match */
if (point <= state->points[mid].point && point > (mid ? state->points[mid-1].point : 0)) {
return state->points[mid].server;
}
/* too low, go up */
if (state->points[mid].point < point) {
lo = mid + 1;
}
else {
hi = mid - 1;
}
}
}
mmc_t *mmc_consistent_find_server(void *s, const char *key, int key_len TSRMLS_DC) /* {{{ */
{
mmc_consistent_state_t *state = s;
mmc_t *mmc;
if (state->num_servers > 1) {
unsigned int i, hash = state->hash(key, key_len);
if (!state->buckets_populated) {
mmc_consistent_populate_buckets(state);
}
mmc = state->buckets[hash % MMC_CONSISTENT_BUCKETS];
/* perform failover if needed */
for (i=0; !mmc_open(mmc, 0, NULL, NULL TSRMLS_CC) && MEMCACHE_G(allow_failover) && i<MEMCACHE_G(max_failover_attempts); i++) {
char *next_key = emalloc(key_len + MAX_LENGTH_OF_LONG + 1);
int next_len = sprintf(next_key, "%s-%d", key, i);
MMC_DEBUG(("mmc_consistent_find_server: failed to connect to server '%s:%d' status %d, trying next", mmc->host, mmc->port, mmc->status));
hash = state->hash(next_key, next_len);
mmc = state->buckets[hash % MMC_CONSISTENT_BUCKETS];
efree(next_key);
}
}
else {
mmc = state->points[0].server;
mmc_open(mmc, 0, NULL, NULL TSRMLS_CC);
}
return mmc->status != MMC_STATUS_FAILED ? mmc : NULL;
}
mmc_t *mmc_standard_find_server(void *s, const char *key, int key_len TSRMLS_DC) /* {{{ */
{
mmc_standard_state_t *state = s;
mmc_t *mmc;
if (state->num_servers > 1) {
unsigned int hash = mmc_hash(state, key, key_len), i;
mmc = state->buckets[hash % state->num_buckets];
/* perform failover if needed */
for (i=0; !mmc_open(mmc, 0, NULL, NULL TSRMLS_CC) && MEMCACHE_G(allow_failover) && i<MEMCACHE_G(max_failover_attempts); i++) {
char *next_key = emalloc(key_len + MAX_LENGTH_OF_LONG + 1);
int next_len = sprintf(next_key, "%d%s", i+1, key);
MMC_DEBUG(("mmc_standard_find_server: failed to connect to server '%s:%d' status %d, trying next", mmc->host, mmc->port, mmc->status));
hash += mmc_hash(state, next_key, next_len);
mmc = state->buckets[hash % state->num_buckets];
efree(next_key);
}
}
else {
mmc = state->buckets[0];
mmc_open(mmc, 0, NULL, NULL TSRMLS_CC);
}
return mmc->status != MMC_STATUS_FAILED ? mmc : NULL;
}
void mmc_consistent_add_server(void *s, mmc_t *mmc, unsigned int weight) /* {{{ */
{
mmc_consistent_state_t *state = s;
int i, key_len, points = weight * MMC_CONSISTENT_POINTS;
/* buffer for "host:port-i\0" */
char *key = emalloc(strlen(mmc->host) + MAX_LENGTH_OF_LONG * 2 + 3);
/* add weight * MMC_CONSISTENT_POINTS number of points for this server */
state->points = erealloc(state->points, sizeof(mmc_consistent_point_t) * (state->num_points + points));
for (i=0; i<points; i++) {
key_len = sprintf(key, "%s:%d-%d", mmc->host, mmc->port, i);
state->points[state->num_points + i].server = mmc;
state->points[state->num_points + i].point = state->hash(key, key_len);
MMC_DEBUG(("mmc_consistent_add_server: key %s, point %lu", key, state->points[state->num_points + i].point));
}
state->num_points += points;
state->num_servers++;
state->buckets_populated = 0;
efree(key);
}
