/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*======
This file is part of PerconaFT.


Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.

----------------------------------------

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License, version 3,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.
======= */

#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."

#pragma once

#include <toku_pthread.h>
#include "test.h"
#include "threaded_stress_test_helpers.h"
#include <portability/toku_atomic.h>

// set this to true for the recovery version of this stress test
// the way this works is to include this header and set 
// crash_at_end = true;
static bool stress_openclose_crash_at_end;

//
// Stress test ft reference counting
//
// Three things keep a fractal tree in memory by holding a reference:
//  - open ft handle
//  - live txn that did a write op
//  - checkpoint
//
// To stress reference counting, we would like threads which:
//  - take checkpoints at random intervals
//  - update random values, random point queries for auditing
//      * sometimes close handle before commit.
//  - close random dictionaries
//
// Here's how we can do it:
//
// A bunch of threads randomly choose from N buckets. Each bucket
// has a DB, an is_open bit, and a lock.
// - in a single txn, each thread will do some small number of
// queries or updates on randomb uckets, opening the dbs if
// they were closed and possibly closing afterwards.
// - this should stress both open db handles and various txns
// references dbs simultaneously.
// 
// and all while this is happening, throw in scanners, updaters,
// and query threads that all assert the contents of these dbs
// is correct, even after recovery.

#define verbose_printf(...)         \
    do {                            \
        if (verbose) {              \
            printf(__VA_ARGS__);    \
            fflush(stdout);         \
        }                           \
    } while (0)

// a bunch of buckets with dbs, a lock, and an is_open bit
// threads will choose buckets randomly for update, query,
// and then maybe open/close the bucket's db.
struct db_bucket {
    DB_ENV *env;
    DB *db;
    bool is_open;
    toku_mutex_t mutex;
};
static struct db_bucket *buckets;
static int num_buckets;

// each operation can do at most this many operations in one txn
static int
choose_random_iteration_count(ARG arg) {
    const int max_iteration_count = 8;
    int k = myrandom_r(arg->random_data) % max_iteration_count;
    return k + 1;
}

// open the ith db in the array, asserting success
static void
open_ith_db(DB_ENV *env, DB **db, int i) {
    char name[30];
    memset(name, 0, sizeof(name));
    get_ith_table_name(name, sizeof(name), i);
    int r = db_create(db, env, 0);
    CKERR(r);
    r = (*db)->open(*db, null_txn, name, NULL, DB_BTREE, 0, 0666);
    CKERR(r);
}

// debugging counter to maintain the invariant that open_buckets <= num_buckets
static int open_buckets;

// choose and lock a random bucket, possibly opening a db
static struct db_bucket *
lock_and_maybe_open_some_db(ARG arg) {
    int k = myrandom_r(arg->random_data) % num_buckets;
    struct db_bucket *bucket = &buckets[k];
    toku_mutex_lock(&bucket->mutex);
    if (!bucket->is_open) {
        // choose a random DB from 0..k-1 to associate with this bucket
        // then, mark the bucket as open.
        int i = myrandom_r(arg->random_data) % num_buckets;
        open_ith_db(bucket->env, &bucket->db, i);
        bucket->is_open = true;
        assert(toku_sync_fetch_and_add(&open_buckets, 1) < num_buckets);
        verbose_printf("opened db %d in bucket %d\n", i, k);
    }
    return bucket;
}

// release the lock on a bucket, possibly closing its db
static void
unlock_and_maybe_close_db(struct db_bucket *bucket, ARG arg) {
    static const int p = 5;
    int k = ((unsigned) myrandom_r(arg->random_data)) % 100;
    // we should close with probability approximately p / 100
    assert(bucket->is_open);
    if (k <= p) {
        DB *db = bucket->db;
        int r = db->close(db, 0);
        CKERR(r);
        bucket->is_open = false;
        int old_open_buckets = toku_sync_fetch_and_sub(&open_buckets, 1);
        assert(old_open_buckets > 0);
        verbose_printf("decided to close a bucket's db before unlocking\n");
    }
    toku_mutex_unlock(&bucket->mutex);
}

// scan some dbs, verifying the correct sum.
static int
scan_some_dbs(DB_TXN *txn, ARG arg, void* operation_extra, void *UU(stats_extra)) {
    int r = 0;
    verbose_printf("scanning some dbs\n");
    struct scan_op_extra* CAST_FROM_VOIDP(extra, operation_extra);
    // scan every db, one by one, and verify that the contents are correct
    for (int i = 0; r == 0 && run_test && i < arg->cli->num_DBs; i++) {
        struct db_bucket *bucket = lock_and_maybe_open_some_db(arg);
        const bool check_sum = true;
        r = scan_op_and_maybe_check_sum(bucket->db, txn, extra, check_sum);
        invariant(r == 0 || r == DB_LOCK_NOTGRANTED);
        unlock_and_maybe_close_db(bucket, arg);
    }
    return r;
}

// update a couple of dbs in some buckets with a txn
static int 
update_some_dbs(DB_TXN *txn, ARG arg, void *op_extra, void *stats_extra) {
    int r = 0;
    verbose_printf("updating some dbs\n");
    const int iterations = choose_random_iteration_count(arg);
    for (int i = 0; r == 0 && run_test && i < iterations; i++) {
        struct db_bucket *bucket = lock_and_maybe_open_some_db(arg);
        // does an update operation on this bucket's db
        r = update_op_db(bucket->db, txn, arg, op_extra, stats_extra);
        invariant(r == 0 || r == DB_LOCK_NOTGRANTED);
        unlock_and_maybe_close_db(bucket, arg);
    }
    return r;
}

// point query a couple of dbs in some buckets with a txn
static int 
ptquery_some_dbs(DB_TXN *txn, ARG arg, void *UU(op_extra), void *UU(stats_extra)) {
    int r = 0;
    verbose_printf("querying some dbs\n");
    const int iterations = choose_random_iteration_count(arg);
    for (int i = 0; r == 0 && run_test && i < iterations; i++) {
        struct db_bucket *bucket = lock_and_maybe_open_some_db(arg);
        // does a point query on a random key for this bucket's db
        const bool check_sum = true;
        r = ptquery_and_maybe_check_op(bucket->db, txn, arg, check_sum);
        invariant(r == 0 || r == DB_LOCK_NOTGRANTED);
        unlock_and_maybe_close_db(bucket, arg);
    }
    return r;
}

static void
stress_table(DB_ENV *env, DB **dbp, struct cli_args *cli_args) {
    const int update_threads = cli_args->num_update_threads;
    const int query_threads = cli_args->num_ptquery_threads;
    const int total_threads = update_threads + query_threads + 1;

    struct arg myargs[total_threads];
    for (int i = 0; i < total_threads; i++) {
        arg_init(&myargs[i], dbp, env, cli_args);
    }

    struct scan_op_extra soe[4];

    // make the forward fast scanner
    soe[0].fast = true;
    soe[0].fwd = true;
    soe[0].prefetch = false;
    myargs[0].operation_extra = &soe[0];
    myargs[0].operation = scan_some_dbs;

    struct update_op_args uoe = get_update_op_args(cli_args, NULL);
    // make the guy that updates the db
    for (int i = 1; i < 1 + update_threads; ++i) {
        myargs[i].operation_extra = &uoe;
        myargs[i].operation = update_some_dbs;
        myargs[i].do_prepare = true;
    }
    // make the guy that does point queries
    for (int i = 1 + update_threads; i < total_threads; i++) {
        myargs[i].operation = ptquery_some_dbs;
        myargs[i].do_prepare = true;
    }

    num_buckets = cli_args->num_DBs;
    open_buckets = num_buckets;
    // each thread gets access to this array of db buckets, from 
    // which they can choose a random db to either touch or query
    XMALLOC_N(num_buckets, buckets);
    for (int i = 0; i < num_buckets; i++) {
        struct db_bucket bucket = {
            .env = env,
            .db = dbp[i], 
            .is_open = true
        };
        buckets[i] = bucket;
        toku_mutex_init(&buckets[i].mutex, NULL);
    }
    // run all of the query and update workers. they may randomly open
    // and close the dbs in each db_bucket to be some random dictionary,
    // so when they're done we'll have to clean up the mess so this
    // stress test can exit gracefully expecting db[i] = the ith db
    //verbose_printf("stressing %d tables using %d update threads, %d query threads\n",
    //        num_buckets, update_threads, query_threads);
    verbose_printf("stressing %d tables using %d update threads\n",
            num_buckets, update_threads);
    // stress_openclose_crash_at_end should be changed to true or false, 
    // depending if this test is for recovery or not.
    const bool crash_at_end = stress_openclose_crash_at_end;
    run_workers(myargs, total_threads, cli_args->num_seconds, crash_at_end, cli_args);
    
    // the stress test is now complete. get ready for shutdown/close.
    //
    // make sure that every db in the original array is opened
    // as it was when it was passed in.
    for (int i = 0; i < num_buckets; i++) {
        // close whatever is open
        if (buckets[i].is_open) {
            DB *db = buckets[i].db; 
            int r = db->close(db, 0);
            CKERR(r);
        }
        // put the correct db back, then save the pointer
        // into the dbp array we were given
        open_ith_db(env, &buckets[i].db, i);
        dbp[i] = buckets[i].db;
    }

    toku_free(buckets);
}
