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redis/src/expire.c

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/* Implementation of EXPIRE (keys with fixed time to live).
*
* ----------------------------------------------------------------------------
*
* Copyright (c) 2009-Present, Redis Ltd.
* All rights reserved.
*
* Licensed under your choice of (a) the Redis Source Available License 2.0
* (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
* GNU Affero General Public License v3 (AGPLv3).
*/
#include "server.h"
/*-----------------------------------------------------------------------------
* Incremental collection of expired keys.
*
* When keys are accessed they are expired on-access. However we need a
* mechanism in order to ensure keys are eventually removed when expired even
* if no access is performed on them.
*----------------------------------------------------------------------------*/
/* Constants table from pow(0.98, 1) to pow(0.98, 16).
* Help calculating the db->avg_ttl. */
static double avg_ttl_factor[16] = {0.98, 0.9604, 0.941192, 0.922368, 0.903921, 0.885842, 0.868126, 0.850763, 0.833748, 0.817073, 0.800731, 0.784717, 0.769022, 0.753642, 0.738569, 0.723798};
/* Helper function for the activeExpireCycle() function.
* This function will try to expire the key-value entry that is stored in the
* hash table entry 'de' of the 'expires' hash table of a Redis database.
*
* If the key is found to be expired, it is removed from the database and
* 1 is returned. Otherwise no operation is performed and 0 is returned.
*
* When a key is expired, server.stat_expiredkeys is incremented.
*
* The parameter 'now' is the current time in milliseconds as is passed
* to the function to avoid too many gettimeofday() syscalls. */
int activeExpireCycleTryExpire(redisDb *db, kvobj *kv, long long now) {
if (now < kvobjGetExpire(kv))
return 0;
enterExecutionUnit(1, 0);
sds key = kvobjGetKey(kv);
robj *keyobj = createStringObject(key,sdslen(key));
deleteExpiredKeyAndPropagate(db,keyobj);
decrRefCount(keyobj);
exitExecutionUnit();
/* Propagate the DEL command */
postExecutionUnitOperations();
return 1;
}
/* Try to expire a few timed out keys. The algorithm used is adaptive and
* will use few CPU cycles if there are few expiring keys, otherwise
* it will get more aggressive to avoid that too much memory is used by
* keys that can be removed from the keyspace.
*
* Every expire cycle tests multiple databases: the next call will start
* again from the next db. No more than CRON_DBS_PER_CALL databases are
* tested at every iteration.
*
* The function can perform more or less work, depending on the "type"
* argument. It can execute a "fast cycle" or a "slow cycle". The slow
* cycle is the main way we collect expired cycles: this happens with
* the "server.hz" frequency (usually 10 hertz).
*
* However the slow cycle can exit for timeout, since it used too much time.
* For this reason the function is also invoked to perform a fast cycle
* at every event loop cycle, in the beforeSleep() function. The fast cycle
* will try to perform less work, but will do it much more often.
*
* The following are the details of the two expire cycles and their stop
* conditions:
*
* If type is ACTIVE_EXPIRE_CYCLE_FAST the function will try to run a
* "fast" expire cycle that takes no longer than ACTIVE_EXPIRE_CYCLE_FAST_DURATION
* microseconds, and is not repeated again before the same amount of time.
* The cycle will also refuse to run at all if the latest slow cycle did not
* terminate because of a time limit condition.
*
* If type is ACTIVE_EXPIRE_CYCLE_SLOW, that normal expire cycle is
* executed, where the time limit is a percentage of the REDIS_HZ period
* as specified by the ACTIVE_EXPIRE_CYCLE_SLOW_TIME_PERC define. In the
* fast cycle, the check of every database is interrupted once the number
* of already expired keys in the database is estimated to be lower than
* a given percentage, in order to avoid doing too much work to gain too
* little memory.
*
* The configured expire "effort" will modify the baseline parameters in
* order to do more work in both the fast and slow expire cycles.
*/
#define ACTIVE_EXPIRE_CYCLE_KEYS_PER_LOOP 20 /* Keys for each DB loop. */
#define ACTIVE_EXPIRE_CYCLE_FAST_DURATION 1000 /* Microseconds. */
#define ACTIVE_EXPIRE_CYCLE_SLOW_TIME_PERC 25 /* Max % of CPU to use. */
#define ACTIVE_EXPIRE_CYCLE_ACCEPTABLE_STALE 10 /* % of stale keys after which
we do extra efforts. */
#define HFE_DB_BASE_ACTIVE_EXPIRE_FIELDS_PER_SEC 10000
/* Data used by the expire dict scan callback. */
typedef struct {
redisDb *db;
long long now;
unsigned long sampled; /* num keys checked */
unsigned long expired; /* num keys expired */
long long ttl_sum; /* sum of ttl for key with ttl not yet expired */
int ttl_samples; /* num keys with ttl not yet expired */
} expireScanData;
void expireScanCallback(void *privdata, const dictEntry *de, dictEntryLink plink) {
UNUSED(plink);
kvobj *kv = dictGetKV(de);
expireScanData *data = privdata;
long long ttl = kvobjGetExpire(kv) - data->now;
if (activeExpireCycleTryExpire(data->db, kv, data->now)) {
data->expired++;
}
if (ttl > 0) {
/* We want the average TTL of keys yet not expired. */
data->ttl_sum += ttl;
data->ttl_samples++;
}
data->sampled++;
}
static inline int isExpiryDictValidForSamplingCb(dict *d) {
long long numkeys = dictSize(d);
unsigned long buckets = dictBuckets(d);
/* When there are less than 1% filled buckets, sampling the key
* space is expensive, so stop here waiting for better times...
* The dictionary will be resized asap. */
if (buckets > DICT_HT_INITIAL_SIZE && (numkeys * 100/buckets < 1)) {
return C_ERR;
}
return C_OK;
}
/* Active expiration Cycle for hash-fields.
*
* Note that releasing fields is expected to be more predictable and rewarding
* than releasing keys because it is stored in `ebuckets` DS which optimized for
* active expiration and in addition the deletion of fields is simple to handle. */
static inline void activeExpireHashFieldCycle(int type) {
/* Remember current db across calls */
static unsigned int currentDb = 0;
/* Tracks the count of fields actively expired for the current database.
* This count continues as long as it fails to actively expire all expired
* fields of currentDb, indicating a possible need to adjust the value of
* maxToExpire. */
static uint64_t activeExpirySequence = 0;
/* Threshold for adjusting maxToExpire */
const uint32_t EXPIRED_FIELDS_TH = 1000000;
redisDb *db = server.db + currentDb;
/* If db is empty, move to next db and return */
if (ebIsEmpty(db->hexpires)) {
activeExpirySequence = 0;
currentDb = (currentDb + 1) % server.dbnum;
return;
}
/* Maximum number of fields to actively expire on a single call */
uint32_t maxToExpire = HFE_DB_BASE_ACTIVE_EXPIRE_FIELDS_PER_SEC / server.hz;
/* If running for a while and didn't manage to active-expire all expired fields of
* currentDb (i.e. activeExpirySequence becomes significant) then adjust maxToExpire */
if ((activeExpirySequence > EXPIRED_FIELDS_TH) && (type == ACTIVE_EXPIRE_CYCLE_SLOW)) {
/* maxToExpire is multiplied by a factor between 1 and 32, proportional to
* the number of times activeExpirySequence exceeded EXPIRED_FIELDS_TH */
uint64_t factor = activeExpirySequence / EXPIRED_FIELDS_TH;
maxToExpire *= (factor<32) ? factor : 32;
}
if (hashTypeDbActiveExpire(db, maxToExpire) == maxToExpire) {
/* active-expire reached maxToExpire limit */
activeExpirySequence += maxToExpire;
} else {
/* Managed to active-expire all expired fields of currentDb */
activeExpirySequence = 0;
currentDb = (currentDb + 1) % server.dbnum;
}
}
void activeExpireCycle(int type) {
/* Adjust the running parameters according to the configured expire
* effort. The default effort is 1, and the maximum configurable effort
* is 10. */
unsigned long
effort = server.active_expire_effort-1, /* Rescale from 0 to 9. */
config_keys_per_loop = ACTIVE_EXPIRE_CYCLE_KEYS_PER_LOOP +
ACTIVE_EXPIRE_CYCLE_KEYS_PER_LOOP/4*effort,
config_cycle_fast_duration = ACTIVE_EXPIRE_CYCLE_FAST_DURATION +
ACTIVE_EXPIRE_CYCLE_FAST_DURATION/4*effort,
config_cycle_slow_time_perc = ACTIVE_EXPIRE_CYCLE_SLOW_TIME_PERC +
2*effort,
config_cycle_acceptable_stale = ACTIVE_EXPIRE_CYCLE_ACCEPTABLE_STALE-
effort;
/* This function has some global state in order to continue the work
* incrementally across calls. */
static unsigned int current_db = 0; /* Next DB to test. */
static int timelimit_exit = 0; /* Time limit hit in previous call? */
static long long last_fast_cycle = 0; /* When last fast cycle ran. */
int j, iteration = 0;
int dbs_per_call = CRON_DBS_PER_CALL;
int dbs_performed = 0;
long long start = ustime(), timelimit, elapsed;
/* If 'expire' action is paused, for whatever reason, then don't expire any key.
* Typically, at the end of the pause we will properly expire the key OR we
* will have failed over and the new primary will send us the expire. */
if (isPausedActionsWithUpdate(PAUSE_ACTION_EXPIRE)) return;
if (type == ACTIVE_EXPIRE_CYCLE_FAST) {
/* Don't start a fast cycle if the previous cycle did not exit
* for time limit, unless the percentage of estimated stale keys is
* too high. Also never repeat a fast cycle for the same period
* as the fast cycle total duration itself. */
if (!timelimit_exit &&
server.stat_expired_stale_perc < config_cycle_acceptable_stale)
return;
if (start < last_fast_cycle + (long long)config_cycle_fast_duration*2)
return;
last_fast_cycle = start;
}
/* We usually should test CRON_DBS_PER_CALL per iteration, with
* two exceptions:
*
* 1) Don't test more DBs than we have.
* 2) If last time we hit the time limit, we want to scan all DBs
* in this iteration, as there is work to do in some DB and we don't want
* expired keys to use memory for too much time. */
if (dbs_per_call > server.dbnum || timelimit_exit)
dbs_per_call = server.dbnum;
/* We can use at max 'config_cycle_slow_time_perc' percentage of CPU
* time per iteration. Since this function gets called with a frequency of
* server.hz times per second, the following is the max amount of
* microseconds we can spend in this function. */
timelimit = config_cycle_slow_time_perc*1000000/server.hz/100;
timelimit_exit = 0;
if (timelimit <= 0) timelimit = 1;
if (type == ACTIVE_EXPIRE_CYCLE_FAST)
timelimit = config_cycle_fast_duration; /* in microseconds. */
/* Accumulate some global stats as we expire keys, to have some idea
* about the number of keys that are already logically expired, but still
* existing inside the database. */
long total_sampled = 0;
long total_expired = 0;
/* Try to smoke-out bugs (server.also_propagate should be empty here) */
serverAssert(server.also_propagate.numops == 0);
/* Stop iteration when one of the following conditions is met:
*
* 1) We have checked a sufficient number of databases with expiration time.
* 2) The time limit has been exceeded.
* 3) All databases have been traversed. */
for (j = 0; dbs_performed < dbs_per_call && timelimit_exit == 0 && j < server.dbnum; j++) {
/* Scan callback data including expired and checked count per iteration. */
expireScanData data;
data.ttl_sum = 0;
data.ttl_samples = 0;
redisDb *db = server.db+(current_db % server.dbnum);
data.db = db;
int db_done = 0; /* The scan of the current DB is done? */
int update_avg_ttl_times = 0, repeat = 0;
/* Increment the DB now so we are sure if we run out of time
* in the current DB we'll restart from the next. This allows to
* distribute the time evenly across DBs. */
current_db++;
/* Interleaving hash-field expiration with key expiration. Better
* call it before handling expired keys because HFE DS is optimized for
* active expiration */
activeExpireHashFieldCycle(type);
if (kvstoreSize(db->expires))
dbs_performed++;
/* Continue to expire if at the end of the cycle there are still
* a big percentage of keys to expire, compared to the number of keys
* we scanned. The percentage, stored in config_cycle_acceptable_stale
* is not fixed, but depends on the Redis configured "expire effort". */
do {
unsigned long num;
iteration++;
/* If there is nothing to expire try next DB ASAP. */
if ((num = kvstoreSize(db->expires)) == 0) {
db->avg_ttl = 0;
break;
}
data.now = mstime();
/* The main collection cycle. Scan through keys among keys
* with an expire set, checking for expired ones. */
data.sampled = 0;
data.expired = 0;
if (num > config_keys_per_loop)
num = config_keys_per_loop;
/* Here we access the low level representation of the hash table
* for speed concerns: this makes this code coupled with dict.c,
* but it hardly changed in ten years.
*
* Note that certain places of the hash table may be empty,
* so we want also a stop condition about the number of
* buckets that we scanned. However scanning for free buckets
* is very fast: we are in the cache line scanning a sequential
* array of NULL pointers, so we can scan a lot more buckets
* than keys in the same time. */
long max_buckets = num*20;
long checked_buckets = 0;
int origin_ttl_samples = data.ttl_samples;
while (data.sampled < num && checked_buckets < max_buckets) {
db->expires_cursor = kvstoreScan(db->expires, db->expires_cursor, -1, expireScanCallback, isExpiryDictValidForSamplingCb, &data);
if (db->expires_cursor == 0) {
db_done = 1;
break;
}
checked_buckets++;
}
total_expired += data.expired;
total_sampled += data.sampled;
/* If find keys with ttl not yet expired, we need to update the average TTL stats once. */
if (data.ttl_samples - origin_ttl_samples > 0) update_avg_ttl_times++;
/* We don't repeat the cycle for the current database if the db is done
* for scanning or an acceptable number of stale keys (logically expired
* but yet not reclaimed). */
repeat = db_done ? 0 : (data.sampled == 0 || (data.expired * 100 / data.sampled) > config_cycle_acceptable_stale);
/* We can't block forever here even if there are many keys to
* expire. So after a given amount of microseconds return to the
* caller waiting for the other active expire cycle. */
if ((iteration & 0xf) == 0 || !repeat) { /* Update the average TTL stats every 16 iterations or about to exit. */
/* Update the average TTL stats for this database,
* because this may reach the time limit. */
if (data.ttl_samples) {
long long avg_ttl = data.ttl_sum / data.ttl_samples;
/* Do a simple running average with a few samples.
* We just use the current estimate with a weight of 2%
* and the previous estimate with a weight of 98%. */
if (db->avg_ttl == 0) {
db->avg_ttl = avg_ttl;
} else {
/* The origin code is as follow.
* for (int i = 0; i < update_avg_ttl_times; i++) {
* db->avg_ttl = (db->avg_ttl/50)*49 + (avg_ttl/50);
* }
* We can convert the loop into a sum of a geometric progression.
* db->avg_ttl = db->avg_ttl * pow(0.98, update_avg_ttl_times) +
* avg_ttl / 50 * (pow(0.98, update_avg_ttl_times - 1) + ... + 1)
* = db->avg_ttl * pow(0.98, update_avg_ttl_times) +
* avg_ttl * (1 - pow(0.98, update_avg_ttl_times))
* = avg_ttl + (db->avg_ttl - avg_ttl) * pow(0.98, update_avg_ttl_times)
* Notice that update_avg_ttl_times is between 1 and 16, we use a constant table
* to accelerate the calculation of pow(0.98, update_avg_ttl_times).*/
db->avg_ttl = avg_ttl + (db->avg_ttl - avg_ttl) * avg_ttl_factor[update_avg_ttl_times - 1] ;
}
update_avg_ttl_times = 0;
data.ttl_sum = 0;
data.ttl_samples = 0;
}
if ((iteration & 0xf) == 0) { /* check time limit every 16 iterations. */
elapsed = ustime()-start;
if (elapsed > timelimit) {
timelimit_exit = 1;
server.stat_expired_time_cap_reached_count++;
break;
}
}
}
} while (repeat);
}
elapsed = ustime()-start;
server.stat_expire_cycle_time_used += elapsed;
latencyAddSampleIfNeeded("expire-cycle",elapsed/1000);
/* Update our estimate of keys existing but yet to be expired.
* Running average with this sample accounting for 5%. */
double current_perc;
if (total_sampled) {
current_perc = (double)total_expired/total_sampled;
} else
current_perc = 0;
server.stat_expired_stale_perc = (current_perc*0.05)+
(server.stat_expired_stale_perc*0.95);
}
/*-----------------------------------------------------------------------------
* Expires of keys created in writable slaves
*
* Normally slaves do not process expires: they wait the masters to synthesize
* DEL operations in order to retain consistency. However writable slaves are
* an exception: if a key is created in the slave and an expire is assigned
* to it, we need a way to expire such a key, since the master does not know
* anything about such a key.
*
* In order to do so, we track keys created in the slave side with an expire
* set, and call the expireSlaveKeys() function from time to time in order to
* reclaim the keys if they already expired.
*
* Note that the use case we are trying to cover here, is a popular one where
* slaves are put in writable mode in order to compute slow operations in
* the slave side that are mostly useful to actually read data in a more
* processed way. Think at sets intersections in a tmp key, with an expire so
* that it is also used as a cache to avoid intersecting every time.
*
* This implementation is currently not perfect but a lot better than leaking
* the keys as implemented in 3.2.
*----------------------------------------------------------------------------*/
/* The dictionary where we remember key names and database ID of keys we may
* want to expire from the slave. Since this function is not often used we
* don't even care to initialize the database at startup. We'll do it once
* the feature is used the first time, that is, when rememberSlaveKeyWithExpire()
* is called.
*
* The dictionary has an SDS string representing the key as the hash table
* key, while the value is a 64 bit unsigned integer with the bits corresponding
* to the DB where the keys may exist set to 1. Currently the keys created
* with a DB id > 63 are not expired, but a trivial fix is to set the bitmap
* to the max 64 bit unsigned value when we know there is a key with a DB
* ID greater than 63, and check all the configured DBs in such a case. */
dict *slaveKeysWithExpire = NULL;
/* Check the set of keys created by the master with an expire set in order to
* check if they should be evicted. */
void expireSlaveKeys(void) {
if (slaveKeysWithExpire == NULL ||
dictSize(slaveKeysWithExpire) == 0) return;
int cycles = 0, noexpire = 0;
mstime_t start = mstime();
while(1) {
dictEntry *de = dictGetRandomKey(slaveKeysWithExpire);
sds keyname = dictGetKey(de);
uint64_t dbids = dictGetUnsignedIntegerVal(de);
uint64_t new_dbids = 0;
/* Check the key against every database corresponding to the
* bits set in the value bitmap. */
int dbid = 0;
while(dbids && dbid < server.dbnum) {
if ((dbids & 1) != 0) {
redisDb *db = server.db+dbid;
kvobj *kv = dbFindExpires(db, keyname);
int expired = kv && activeExpireCycleTryExpire(server.db+dbid, kv, start);
/* If the key was not expired in this DB, we need to set the
* corresponding bit in the new bitmap we set as value.
* At the end of the loop if the bitmap is zero, it means we
* no longer need to keep track of this key. */
if (kv && !expired) {
noexpire++;
new_dbids |= (uint64_t)1 << dbid;
}
}
dbid++;
dbids >>= 1;
}
/* Set the new bitmap as value of the key, in the dictionary
* of keys with an expire set directly in the writable slave. Otherwise
* if the bitmap is zero, we no longer need to keep track of it. */
if (new_dbids)
dictSetUnsignedIntegerVal(de,new_dbids);
else
dictDelete(slaveKeysWithExpire,keyname);
/* Stop conditions: found 3 keys we can't expire in a row or
* time limit was reached. */
cycles++;
if (noexpire > 3) break;
if ((cycles % 64) == 0 && mstime()-start > 1) break;
if (dictSize(slaveKeysWithExpire) == 0) break;
}
}
/* Track keys that received an EXPIRE or similar command in the context
* of a writable slave. */
void rememberSlaveKeyWithExpire(redisDb *db, sds key) {
if (slaveKeysWithExpire == NULL) {
static dictType dt = {
dictSdsHash, /* hash function */
NULL, /* key dup */
NULL, /* val dup */
dictSdsKeyCompare, /* key compare */
dictSdsDestructor, /* key destructor */
NULL, /* val destructor */
NULL /* allow to expand */
};
slaveKeysWithExpire = dictCreate(&dt);
}
if (db->id > 63) return;
dictEntry *de = dictAddOrFind(slaveKeysWithExpire, key);
/* If the entry was just created, set it to a copy of the SDS string
* representing the key: we don't want to need to take those keys
* in sync with the main DB. The keys will be removed by expireSlaveKeys()
* as it scans to find keys to remove. */
if (dictGetKey(de) == key) {
dictSetKey(slaveKeysWithExpire, de, sdsdup(key));
dictSetUnsignedIntegerVal(de,0);
}
uint64_t dbids = dictGetUnsignedIntegerVal(de);
dbids |= (uint64_t)1 << db->id;
dictSetUnsignedIntegerVal(de,dbids);
}
/* Return the number of keys we are tracking. */
size_t getSlaveKeyWithExpireCount(void) {
if (slaveKeysWithExpire == NULL) return 0;
return dictSize(slaveKeysWithExpire);
}
/* Remove the keys in the hash table. We need to do that when data is
* flushed from the server. We may receive new keys from the master with
* the same name/db and it is no longer a good idea to expire them.
*
* Note: technically we should handle the case of a single DB being flushed
* but it is not worth it since anyway race conditions using the same set
* of key names in a writable slave and in its master will lead to
* inconsistencies. This is just a best-effort thing we do. */
void flushSlaveKeysWithExpireList(void) {
if (slaveKeysWithExpire) {
dictRelease(slaveKeysWithExpire);
slaveKeysWithExpire = NULL;
}
}
int checkAlreadyExpired(long long when) {
/* EXPIRE with negative TTL, or EXPIREAT with a timestamp into the past
* should never be executed as a DEL when load the AOF or in the context
* of a slave instance.
*
* Instead we add the already expired key to the database with expire time
* (possibly in the past) and wait for an explicit DEL from the master. */
return (when <= commandTimeSnapshot() && !server.loading && !server.masterhost);
}
#define EXPIRE_NX (1<<0)
#define EXPIRE_XX (1<<1)
#define EXPIRE_GT (1<<2)
#define EXPIRE_LT (1<<3)
/* Parse additional flags of expire commands
*
* Supported flags:
* - NX: set expiry only when the key has no expiry
* - XX: set expiry only when the key has an existing expiry
* - GT: set expiry only when the new expiry is greater than current one
* - LT: set expiry only when the new expiry is less than current one */
int parseExtendedExpireArgumentsOrReply(client *c, int *flags) {
int nx = 0, xx = 0, gt = 0, lt = 0;
int j = 3;
while (j < c->argc) {
char *opt = c->argv[j]->ptr;
if (!strcasecmp(opt,"nx")) {
*flags |= EXPIRE_NX;
nx = 1;
} else if (!strcasecmp(opt,"xx")) {
*flags |= EXPIRE_XX;
xx = 1;
} else if (!strcasecmp(opt,"gt")) {
*flags |= EXPIRE_GT;
gt = 1;
} else if (!strcasecmp(opt,"lt")) {
*flags |= EXPIRE_LT;
lt = 1;
} else {
addReplyErrorFormat(c, "Unsupported option %s", opt);
return C_ERR;
}
j++;
}
if ((nx && xx) || (nx && gt) || (nx && lt)) {
addReplyError(c, "NX and XX, GT or LT options at the same time are not compatible");
return C_ERR;
}
if (gt && lt) {
addReplyError(c, "GT and LT options at the same time are not compatible");
return C_ERR;
}
return C_OK;
}
/*-----------------------------------------------------------------------------
* Expires Commands
*----------------------------------------------------------------------------*/
/* This is the generic command implementation for EXPIRE, PEXPIRE, EXPIREAT
* and PEXPIREAT. Because the command second argument may be relative or absolute
* the "basetime" argument is used to signal what the base time is (either 0
* for *AT variants of the command, or the current time for relative expires).
*
* unit is either UNIT_SECONDS or UNIT_MILLISECONDS, and is only used for
* the argv[2] parameter. The basetime is always specified in milliseconds.
*
* Additional flags are supported and parsed via parseExtendedExpireArguments */
void expireGenericCommand(client *c, long long basetime, int unit) {
robj *key = c->argv[1], *param = c->argv[2];
long long when; /* unix time in milliseconds when the key will expire. */
long long current_expire = -1;
int flag = 0;
/* checking optional flags */
if (parseExtendedExpireArgumentsOrReply(c, &flag) != C_OK) {
return;
}
if (getLongLongFromObjectOrReply(c, param, &when, NULL) != C_OK)
return;
/* EXPIRE allows negative numbers, but we can at least detect an
* overflow by either unit conversion or basetime addition. */
if (unit == UNIT_SECONDS) {
if (when > LLONG_MAX / 1000 || when < LLONG_MIN / 1000) {
addReplyErrorExpireTime(c);
return;
}
when *= 1000;
}
if (when > LLONG_MAX - basetime) {
addReplyErrorExpireTime(c);
return;
}
when += basetime;
/* No key, return zero. */
kvobj *kv = lookupKeyWrite(c->db,key);
if (kv == NULL) {
addReply(c,shared.czero);
return;
}
if (flag) {
current_expire = kvobjGetExpire(kv);
/* NX option is set, check current expiry */
if (flag & EXPIRE_NX) {
if (current_expire != -1) {
addReply(c,shared.czero);
return;
}
}
/* XX option is set, check current expiry */
if (flag & EXPIRE_XX) {
if (current_expire == -1) {
/* reply 0 when the key has no expiry */
addReply(c,shared.czero);
return;
}
}
/* GT option is set, check current expiry */
if (flag & EXPIRE_GT) {
/* When current_expire is -1, we consider it as infinite TTL,
* so expire command with gt always fail the GT. */
if (when <= current_expire || current_expire == -1) {
/* reply 0 when the new expiry is not greater than current */
addReply(c,shared.czero);
return;
}
}
/* LT option is set, check current expiry */
if (flag & EXPIRE_LT) {
/* When current_expire -1, we consider it as infinite TTL,
* but 'when' can still be negative at this point, so if there is
* an expiry on the key and it's not less than current, we fail the LT. */
if (current_expire != -1 && when >= current_expire) {
/* reply 0 when the new expiry is not less than current */
addReply(c,shared.czero);
return;
}
}
}
if (checkAlreadyExpired(when)) {
robj *aux;
int deleted = dbGenericDelete(c->db,key,server.lazyfree_lazy_expire,DB_FLAG_KEY_EXPIRED);
serverAssertWithInfo(c,key,deleted);
server.dirty++;
/* Replicate/AOF this as an explicit DEL or UNLINK. */
aux = server.lazyfree_lazy_expire ? shared.unlink : shared.del;
rewriteClientCommandVector(c,2,aux,key);
signalModifiedKey(c,c->db,key);
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",key,c->db->id);
addReply(c, shared.cone);
return;
} else {
setExpire(c,c->db,key,when);
addReply(c,shared.cone);
/* Propagate as PEXPIREAT millisecond-timestamp
* Only rewrite the command arg if not already PEXPIREAT */
if (c->cmd->proc != pexpireatCommand) {
rewriteClientCommandArgument(c,0,shared.pexpireat);
}
/* Avoid creating a string object when it's the same as argv[2] parameter */
if (basetime != 0 || unit == UNIT_SECONDS) {
robj *when_obj = createStringObjectFromLongLong(when);
rewriteClientCommandArgument(c,2,when_obj);
decrRefCount(when_obj);
}
signalModifiedKey(c,c->db,key);
notifyKeyspaceEvent(NOTIFY_GENERIC,"expire",key,c->db->id);
server.dirty++;
return;
}
}
/* EXPIRE key seconds [ NX | XX | GT | LT] */
void expireCommand(client *c) {
expireGenericCommand(c,commandTimeSnapshot(),UNIT_SECONDS);
}
/* EXPIREAT key unix-time-seconds [ NX | XX | GT | LT] */
void expireatCommand(client *c) {
expireGenericCommand(c,0,UNIT_SECONDS);
}
/* PEXPIRE key milliseconds [ NX | XX | GT | LT] */
void pexpireCommand(client *c) {
expireGenericCommand(c,commandTimeSnapshot(),UNIT_MILLISECONDS);
}
/* PEXPIREAT key unix-time-milliseconds [ NX | XX | GT | LT] */
void pexpireatCommand(client *c) {
expireGenericCommand(c,0,UNIT_MILLISECONDS);
}
/* Implements TTL, PTTL, EXPIRETIME and PEXPIRETIME */
void ttlGenericCommand(client *c, int output_ms, int output_abs) {
long long expire, ttl = -1;
/* If the key does not exist at all, return -2 */
kvobj *kv = lookupKeyReadWithFlags(c->db,c->argv[1],LOOKUP_NOTOUCH);
if (kv == NULL) {
addReplyLongLong(c,-2);
return;
}
/* The key exists. Return -1 if it has no expire, or the actual
* TTL value otherwise. */
expire = kvobjGetExpire(kv);
if (expire != -1) {
ttl = output_abs ? expire : expire-commandTimeSnapshot();
if (ttl < 0) ttl = 0;
}
if (ttl == -1) {
addReplyLongLong(c,-1);
} else {
addReplyLongLong(c,output_ms ? ttl : ((ttl+500)/1000));
}
}
/* TTL key */
void ttlCommand(client *c) {
ttlGenericCommand(c, 0, 0);
}
/* PTTL key */
void pttlCommand(client *c) {
ttlGenericCommand(c, 1, 0);
}
/* EXPIRETIME key */
void expiretimeCommand(client *c) {
ttlGenericCommand(c, 0, 1);
}
/* PEXPIRETIME key */
void pexpiretimeCommand(client *c) {
ttlGenericCommand(c, 1, 1);
}
/* PERSIST key */
void persistCommand(client *c) {
if (lookupKeyWrite(c->db,c->argv[1])) {
if (removeExpire(c->db,c->argv[1])) {
signalModifiedKey(c,c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_GENERIC,"persist",c->argv[1],c->db->id);
addReply(c,shared.cone);
server.dirty++;
} else {
addReply(c,shared.czero);
}
} else {
addReply(c,shared.czero);
}
}
/* TOUCH key1 [key2 key3 ... keyN] */
void touchCommand(client *c) {
int touched = 0;
for (int j = 1; j < c->argc; j++)
if (lookupKeyRead(c->db,c->argv[j]) != NULL) touched++;
addReplyLongLong(c,touched);
}
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