[t:4028], add test that demonstrates the problem

git-svn-id: file:///svn/toku/tokudb@39281 c7de825b-a66e-492c-adef-691d508d4ae1

src/tests/perf_checkpoint_var.c

+/* -*- mode: C; c-basic-offset: 4 -*- */
+#ident "Copyright (c) 2007 Tokutek Inc.  All rights reserved."
+#ident "$Id: test_stress1.c 39258 2012-01-27 13:51:58Z zardosht $"
+#include "test.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <toku_pthread.h>
+#include <unistd.h>
+#include <memory.h>
+#include <sys/stat.h>
+#include <db.h>
+
+#include "threaded_stress_test_helpers.h"
+
+//
+// This test is a form of stress that does operations on a single dictionary:
+// We create a dictionary bigger than the cachetable (around 4x greater).
+// Then, we spawn a bunch of pthreads that do the following:
+//  - scan dictionary forward with bulk fetch
+//  - scan dictionary forward slowly
+//  - scan dictionary backward with bulk fetch
+//  - scan dictionary backward slowly
+//  - Grow the dictionary with insertions
+//  - do random point queries into the dictionary
+// With the small cachetable, this should produce quite a bit of churn in reading in and evicting nodes.
+// If the test runs to completion without crashing, we consider it a success. It also tests that snapshots
+// work correctly by verifying that table scans sum their vals to 0.
+//
+// This does NOT test:
+//  - splits and merges
+//  - multiple DBs
+//
+// Variables that are interesting to tweak and run:
+//  - small cachetable
+//  - number of elements
+//
+
+static int checkpoint_var(DB_TXN *txn, ARG arg, void* operation_extra) {
+    int db_index = random()%arg->num_DBs;
+    int r = 0;
+    int val_size = *(int *)operation_extra;
+    DB* db = arg->dbp[db_index];
+    char data[val_size];
+    memset(data, 0, sizeof(data));
+    for (int i = 0; i < 10; i++) {
+        // do point queries
+        ptquery_and_maybe_check_op(db, txn, arg, FALSE);        
+    }
+    for (int i = 0; i < 20; i++) {
+        // do a random insertion
+        int rand_key = random() % arg->num_elements;
+        DBT key, val;
+        r = db->put(
+            db, 
+            txn, 
+            dbt_init(&key, &rand_key, sizeof(rand_key)), 
+            dbt_init(&val, data, sizeof(data)), 
+            0);
+        if (r != 0) {
+            goto cleanup;
+        }
+    }
+cleanup:
+    return r;
+}
+
+
+static void
+stress_table(DB_ENV* env, DB** dbp, struct cli_args *cli_args) {
+    int n = cli_args->num_elements;
+    //
+    // the threads that we want:
+    //   - some threads constantly updating random values
+    //   - one thread doing table scan with bulk fetch
+    //   - one thread doing table scan without bulk fetch
+    //   - some threads doing random point queries
+    //
+
+    if (verbose) printf("starting creation of pthreads\n");
+    int val_size = cli_args->val_size;
+    const int num_threads = cli_args->num_ptquery_threads;
+    struct arg myargs[num_threads];
+    for (int i = 0; i < num_threads; i++) {
+        arg_init(&myargs[i], n, dbp, env, cli_args);
+    }
+    for (int i = 0; i < num_threads; i++) {
+        myargs[i].operation = checkpoint_var;
+        myargs[i].operation_extra = &val_size;
+    }
+    run_workers(myargs, num_threads, cli_args->time_of_test, false, cli_args);
+}
+
+int
+test_main(int argc, char *const argv[]) {
+    struct cli_args args = get_default_args_for_perf();
+    parse_stress_test_args(argc, argv, &args);
+    stress_test_main(&args);
+    return 0;
+}