Function rdbSaveRio

src/rdb.cpp:1314–1412

Produces a dump of the database in RDB format sending it to the specified * Redis I/O channel. On success C_OK is returned, otherwise C_ERR * is returned and part of the output, or all the output, can be * missing because of I/O errors. * * When the function returns C_ERR and if 'error' is not NULL, the * integer pointed by 'error' is set to the value of errno just after the I/O * error. */

 * integer pointed by 'error' is set to the value of errno just after the I/O
 * error. */
int rdbSaveRio(rio *rdb, const redisDbPersistentDataSnapshot **rgpdb, int *error, int rdbflags, rdbSaveInfo *rsi) {
    dictEntry *de;
    dictIterator *di = NULL;
    char magic[10];
    uint64_t cksum;
    size_t processed = 0;
    int j;
    long key_count = 0;
    long long info_updated_time = 0;
    const char *pname = (rdbflags & RDBFLAGS_AOF_PREAMBLE) ? "AOF rewrite" :  "RDB";

    if (g_pserver->rdb_checksum)
        rdb->update_cksum = rioGenericUpdateChecksum;
    snprintf(magic,sizeof(magic),"REDIS%04d",RDB_VERSION);
    if (rdbWriteRaw(rdb,magic,9) == -1) goto werr;
    if (rdbSaveInfoAuxFields(rdb,rdbflags,rsi) == -1) goto werr;
    if (rdbSaveModulesAux(rdb, REDISMODULE_AUX_BEFORE_RDB) == -1) goto werr;

    for (j = 0; j < cserver.dbnum; j++) {
        const redisDbPersistentDataSnapshot *db = rgpdb != nullptr ? rgpdb[j] : g_pserver->db[j];
        if (db->size() == 0) continue;

        /* Write the SELECT DB opcode */
        if (rdbSaveType(rdb,RDB_OPCODE_SELECTDB) == -1) goto werr;
        if (rdbSaveLen(rdb,j) == -1) goto werr;

        /* Write the RESIZE DB opcode. */
        uint64_t db_size, expires_size;
        db_size = db->size();
        expires_size = db->expireSize();
        if (rdbSaveType(rdb,RDB_OPCODE_RESIZEDB) == -1) goto werr;
        if (rdbSaveLen(rdb,db_size) == -1) goto werr;
        if (rdbSaveLen(rdb,expires_size) == -1) goto werr;
        
        /* Iterate this DB writing every entry */
        size_t ckeysExpired = 0;
        bool fSavedAll = db->iterate_threadsafe([&](const char *keystr, robj_roptr o)->bool {
            if (o->FExpires())
                ++ckeysExpired;
            
            if (!saveKey(rdb, rdbflags, &processed, keystr, o))
                return false;

            /* Update child info every 1 second (approximately).
             * in order to avoid calling mstime() on each iteration, we will
             * check the diff every 1024 keys */
            if ((key_count++ & 1023) == 0) {
                long long now = mstime();
                if (now - info_updated_time >= 1000) {
                    sendChildInfo(CHILD_INFO_TYPE_CURRENT_INFO, key_count, pname);
                    info_updated_time = now;
                }
            }

            return !g_pserver->rdbThreadVars.fRdbThreadCancel;
        });
        if (!fSavedAll)
            goto werr;