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hdb: Test LMDB and SQLite3 HDB concurrency

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Test that we can dump an HDB w/o blocking write transactions.

This currently works for different processes (both backends), but not
for threads (for either backend), and it's not yet clear why.
This commit is contained in:
Nicolas Williams
2020-10-06 12:08:18 -05:00
parent 8c7900c40b
commit f87ba4f23b
3 changed files with 472 additions and 2 deletions
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5
lib/hdb/Makefile.am
View File

@@ -78,8 +78,8 @@ libhdb_la_LDFLAGS += $(LDFLAGS_VERSION_SCRIPT)$(srcdir)/version-script.map
endif
# test_hdbkeys and test_mkey are not tests -- they are manual test utils
noinst_PROGRAMS = test_dbinfo test_hdbkeys test_mkey test_namespace
TESTS = test_dbinfo test_namespace
noinst_PROGRAMS = test_dbinfo test_hdbkeys test_mkey test_namespace test_concurrency
TESTS = test_dbinfo test_namespace test_concurrency
dist_libhdb_la_SOURCES = \
common.c \
@@ -126,6 +126,7 @@ ALL_OBJECTS += $(test_dbinfo_OBJECTS)
ALL_OBJECTS += $(test_hdbkeys_OBJECTS)
ALL_OBJECTS += $(test_mkey_OBJECTS)
ALL_OBJECTS += $(test_namespace_OBJECTS)
ALL_OBJECTS += $(test_concurrency_OBJECTS)
$(ALL_OBJECTS): $(HDB_PROTOS) hdb_asn1.h hdb_asn1-priv.h hdb_err.h

17
lib/hdb/hdb-sqlite.c
View File

@@ -41,6 +41,7 @@ typedef struct hdb_sqlite_db {
sqlite3 *db;
char *db_file;
sqlite3_stmt *connect;
sqlite3_stmt *get_version;
sqlite3_stmt *fetch;
sqlite3_stmt *get_ids;
@@ -82,6 +83,9 @@ typedef struct hdb_sqlite_db {
" DELETE FROM Principal" \
" WHERE entry = OLD.id;" \
" END"
#define HDBSQLITE_CONNECT \
" PRAGMA read_uncommitted = false;" \
" PRAGMA journal_mode = WAL"
#define HDBSQLITE_GET_VERSION \
" SELECT number FROM Version"
#define HDBSQLITE_FETCH \
@@ -155,6 +159,11 @@ prep_stmts(krb5_context context, hdb_sqlite_db *hsdb)
{
int ret;
ret = hdb_sqlite_prepare_stmt(context, hsdb->db,
&hsdb->connect,
HDBSQLITE_CONNECT);
if (ret)
return ret;
ret = hdb_sqlite_prepare_stmt(context, hsdb->db,
&hsdb->get_version,
HDBSQLITE_GET_VERSION);
@@ -209,6 +218,10 @@ prep_stmts(krb5_context context, hdb_sqlite_db *hsdb)
static void
finalize_stmts(krb5_context context, hdb_sqlite_db *hsdb)
{
if (hsdb->connect != NULL)
sqlite3_finalize(hsdb->connect);
hsdb->connect = NULL;
if (hsdb->get_version != NULL)
sqlite3_finalize(hsdb->get_version);
hsdb->get_version = NULL;
@@ -316,6 +329,8 @@ bind_principal(krb5_context context, krb5_const_principal principal, sqlite3_stm
return 0;
}
static int hdb_sqlite_step(krb5_context, sqlite3 *, sqlite3_stmt *);
/**
* Opens an sqlite3 database handle to a file, may create the
* database file depending on flags.
@@ -347,6 +362,8 @@ hdb_sqlite_open_database(krb5_context context, HDB *db, int flags)
return ret;
}
(void) hdb_sqlite_step(context, hsdb->db, hsdb->connect);
sqlite3_reset(hsdb->connect);
return 0;
}

452
lib/hdb/test_concurrency.c Normal file
View File

@@ -0,0 +1,452 @@
/*
* Copyright (c) 2005 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* This test tries to test reader/writer concurrency for the SQLite3 and LMDB
* HDB backends. We're hoping to find that one thread or process can dump the
* HDB while another writes -- this way backups and ipropd-master need not
* block write transactions when dumping a huge HDB.
*
* It has two modes: threaded, and forked.
*
* Apparently, neither LMDB nor SQLite3 give us the desired level of
* concurrency in threaded mode, with this test not making progress. This is
* surprising, at least for SQLite3, which is supposed to support N readers, 1
* writer and be thread-safe. LMDB also is supposed to support N readers, 1
* writers, but perhaps not all in one process?
*/
#include "hdb_locl.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <pthread.h>
#include <getarg.h>
static int use_threads;
static int help_flag;
static int version_flag;
struct tsync {
pthread_mutex_t lock;
pthread_cond_t rcv;
pthread_cond_t wcv;
const char *hdb_name;
const char *fname;
volatile int writer_go;
volatile int reader_go;
int writer_go_pipe[2];
int reader_go_pipe[2];
};
static void *
threaded_reader(void *d)
{
krb5_error_code ret;
krb5_context context;
struct tsync *s = d;
hdb_entry_ex entr;
HDB *dbr = NULL;
printf("Reader thread opening HDB\n");
if ((krb5_init_context(&context)))
errx(1, "krb5_init_context failed");
/* Open a new HDB handle to read */
if ((ret = hdb_create(context, &dbr, s->hdb_name))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not get a handle for HDB %s (read)",
s->hdb_name);
}
if ((ret = dbr->hdb_open(context, dbr, O_RDONLY, 0))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not open HDB %s", s->hdb_name);
}
if ((ret = dbr->hdb_firstkey(context, dbr, 0, &entr))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not iterate HDB %s", s->hdb_name);
}
free_hdb_entry(&entr.entry);
/* Tell the writer to go ahead and write */
printf("Reader thread iterated one entry; telling writer to write more\n");
s->writer_go = 1;
(void) pthread_mutex_lock(&s->lock);
(void) pthread_cond_signal(&s->wcv);
/* Wait for the writer to have written one more entry to the HDB */
printf("Reader thread waiting for writer\n");
while (!s->reader_go)
(void) pthread_cond_wait(&s->rcv, &s->lock);
/* Iterate the rest */
printf("Reader thread iterating another entry\n");
if ((ret = dbr->hdb_nextkey(context, dbr, 0, &entr))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret,
"Could not iterate while writing to HDB %s", s->hdb_name);
}
printf("Reader thread iterated another entry\n");
free_hdb_entry(&entr.entry);
if ((ret = dbr->hdb_nextkey(context, dbr, 0, &entr)) == 0) {
//(void) unlink(s->fname);
krb5_warn(context, ret,
"HDB %s sees writes committed since starting iteration",
s->hdb_name);
} else if (ret != HDB_ERR_NOENTRY) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret,
"Could not iterate while writing to HDB %s (2)", s->hdb_name);
}
/* Tell the writer we're done */
printf("Reader thread telling writer to go\n");
s->writer_go = 1;
(void) pthread_cond_signal(&s->wcv);
(void) pthread_mutex_unlock(&s->lock);
dbr->hdb_close(context, dbr);
dbr->hdb_destroy(context, dbr);
krb5_free_context(context);
printf("Reader thread exiting\n");
return 0;
}
static void
forked_reader(struct tsync *s)
{
krb5_error_code ret;
krb5_context context;
hdb_entry_ex entr;
ssize_t bytes;
char b[1];
HDB *dbr = NULL;
printf("Reader process opening HDB\n");
(void) close(s->writer_go_pipe[0]);
(void) close(s->reader_go_pipe[1]);
s->writer_go_pipe[0] = -1;
s->reader_go_pipe[1] = -1;
if ((krb5_init_context(&context)))
errx(1, "krb5_init_context failed");
/* Open a new HDB handle to read */
if ((ret = hdb_create(context, &dbr, s->hdb_name))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not get a handle for HDB %s (read)",
s->hdb_name);
}
if ((ret = dbr->hdb_open(context, dbr, O_RDONLY, 0))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not open HDB %s", s->hdb_name);
}
if ((ret = dbr->hdb_firstkey(context, dbr, 0, &entr))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret, "Could not iterate HDB %s", s->hdb_name);
}
free_hdb_entry(&entr.entry);
/* Tell the writer to go ahead and write */
printf("Reader process iterated one entry; telling writer to write more\n");
while ((bytes = write(s->writer_go_pipe[1], "", sizeof(""))) == -1 &&
errno == EINTR)
;
/* Wait for the writer to have written one more entry to the HDB */
printf("Reader process waiting for writer\n");
while ((bytes = read(s->reader_go_pipe[0], b, sizeof(b))) == -1 &&
errno == EINTR)
;
if (bytes == -1)
err(1, "Could not read from reader-go pipe (error)");
if (bytes == 0)
errx(1, "Could not read from reader-go pipe (EOF)");
/* Iterate the rest */
printf("Reader process iterating another entry\n");
if ((ret = dbr->hdb_nextkey(context, dbr, 0, &entr))) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret,
"Could not iterate while writing to HDB %s", s->hdb_name);
}
free_hdb_entry(&entr.entry);
printf("Reader process iterated another entry\n");
if ((ret = dbr->hdb_nextkey(context, dbr, 0, &entr)) == 0) {
//(void) unlink(s->fname);
krb5_warn(context, ret,
"HDB %s sees writes committed since starting iteration (%s)",
s->hdb_name, entr.entry.principal->name.name_string.val[0]);
} else if (ret != HDB_ERR_NOENTRY) {
//(void) unlink(s->fname);
krb5_err(context, 1, ret,
"Could not iterate while writing to HDB %s (2)", s->hdb_name);
}
/* Tell the writer we're done */
printf("Reader process done; telling writer to go\n");
while ((bytes = write(s->writer_go_pipe[1], "", sizeof(""))) == -1 &&
errno == EINTR)
;
dbr->hdb_close(context, dbr);
dbr->hdb_destroy(context, dbr);
krb5_free_context(context);
(void) close(s->writer_go_pipe[1]);
(void) close(s->reader_go_pipe[0]);
printf("Reader process exiting\n");
_exit(0);
}
static krb5_error_code
make_entry(krb5_context context, hdb_entry_ex *entry, const char *name)
{
krb5_error_code ret;
memset(entry, 0, sizeof(*entry));
entry->entry.kvno = 2;
entry->entry.keys.len = 0;
entry->entry.keys.val = NULL;
entry->entry.created_by.time = time(NULL);
entry->entry.modified_by = NULL;
entry->entry.valid_start = NULL;
entry->entry.valid_end = NULL;
entry->entry.max_life = NULL;
entry->entry.max_renew = NULL;
entry->entry.etypes = NULL;
entry->entry.generation = NULL;
entry->entry.extensions = NULL;
if ((ret = krb5_make_principal(context, &entry->entry.principal,
"TEST.H5L.SE", name, NULL)))
return ret;
if ((ret = krb5_make_principal(context, &entry->entry.created_by.principal,
"TEST.H5L.SE", "tester", NULL)))
return ret;
return 0;
}
static void
test_hdb_concurrency(char *name, const char *ext)
{
krb5_error_code ret;
krb5_context context;
char *fname = strchr(name, ':') + 1;
char *fname_ext = NULL;
pthread_t reader_thread;
struct tsync ts;
hdb_entry_ex entw;
pid_t child = getpid();
HDB *dbw = NULL;
int status;
int fd;
memset(&ts, 0, sizeof(ts));
(void) pthread_cond_init(&ts.rcv, NULL);
(void) pthread_cond_init(&ts.wcv, NULL);
(void) pthread_mutex_init(&ts.lock, NULL);
if ((krb5_init_context(&context)))
errx(1, "krb5_init_context failed");
/* Use mkstemp() then unlink() to avoid warnings about mktemp(); ugh */
if ((fd = mkstemp(fname)) == -1)
err(1, "mkstemp(%s)", fname);
(void) close(fd);
(void) unlink(fname);
if (asprintf(&fname_ext, "%s%s", fname, ext ? ext : "") == -1 ||
fname_ext == NULL)
err(1, "Out of memory");
ts.hdb_name = name;
ts.fname = fname_ext;
printf("Writing two entries into HDB\n");
if ((ret = hdb_create(context, &dbw, name)))
krb5_err(context, 1, ret, "Could not get a handle for HDB %s (write)",
name);
if ((ret = dbw->hdb_open(context, dbw, O_RDWR | O_CREAT, 0600)))
krb5_err(context, 1, ret, "Could not create HDB %s", name);
/* Add two entries */
memset(&entw, 0, sizeof(entw));
if ((ret = make_entry(context, &entw, "foo")) ||
(ret = dbw->hdb_store(context, dbw, 0, &entw))) {
(void) unlink(fname_ext);
krb5_err(context, 1, ret,
"Could not store entry for \"foo\" in HDB %s", name);
}
free_hdb_entry(&entw.entry);
if ((ret = make_entry(context, &entw, "bar")) ||
(ret = dbw->hdb_store(context, dbw, 0, &entw))) {
(void) unlink(fname_ext);
krb5_err(context, 1, ret,
"Could not store entry for \"foo\" in HDB %s", name);
}
free_hdb_entry(&entw.entry);
if (use_threads) {
printf("Starting reader thread\n");
(void) pthread_mutex_lock(&ts.lock);
if ((errno = pthread_create(&reader_thread, NULL, threaded_reader, &ts))) {
(void) unlink(fname_ext);
krb5_err(context, 1, ret, "Could not create a thread to read HDB");
}
/* Wait for reader */
while (!ts.writer_go)
(void) pthread_cond_wait(&ts.wcv, &ts.lock);
(void) pthread_mutex_unlock(&ts.lock);
} else {
printf("Starting reader process\n");
if (pipe(ts.writer_go_pipe) == -1)
err(1, "Could not create a pipe");
if (pipe(ts.reader_go_pipe) == -1)
err(1, "Could not create a pipe");
switch ((child = fork())) {
case -1: err(1, "Could not fork a child");
case 0: forked_reader(&ts); _exit(0);
default: break;
}
(void) close(ts.writer_go_pipe[1]);
ts.writer_go_pipe[1] = -1;
}
/* Store one more entry */
if ((ret = make_entry(context, &entw, "foobar")) ||
(ret = dbw->hdb_store(context, dbw, 0, &entw))) {
(void) unlink(fname_ext);
krb5_err(context, 1, ret,
"Could not store entry for \"foobar\" in HDB %s "
"while iterating it", name);
}
free_hdb_entry(&entw.entry);
if (use_threads) {
(void) pthread_mutex_lock(&ts.lock);
ts.reader_go = 1;
(void) pthread_cond_signal(&ts.rcv);
while (!ts.writer_go)
(void) pthread_cond_wait(&ts.wcv, &ts.lock);
} else {
ssize_t bytes;
char b[1];
while ((bytes = write(ts.reader_go_pipe[1], "", sizeof(""))) == -1 &&
errno == EINTR)
;
if (bytes == -1) {
kill(child, SIGKILL);
err(1, "Could not write to reader-go pipe (error)");
}
if (bytes == 0) {
kill(child, SIGKILL);
err(1, "Could not write to reader-go pipe (EOF?)");
}
while ((bytes = read(ts.writer_go_pipe[0], b, sizeof(b))) == -1 &&
errno == EINTR)
;
if (bytes == -1) {
kill(child, SIGKILL);
err(1, "Could not read from writer-go pipe");
}
if (bytes == 0) {
kill(child, SIGKILL);
errx(1, "Child errored");
}
}
dbw->hdb_close(context, dbw);
dbw->hdb_destroy(context, dbw);
if (use_threads) {
(void) pthread_join(reader_thread, NULL);
} else {
(void) close(ts.writer_go_pipe[1]);
(void) close(ts.reader_go_pipe[0]);
(void) close(ts.reader_go_pipe[1]);
while (wait(&status) == -1 && errno == EINTR)
;
(void) close(ts.writer_go_pipe[0]);
if (!WIFEXITED(status))
errx(1, "Child reader died");
if (WEXITSTATUS(status) != 0)
errx(1, "Child reader errored");
}
(void) unlink(fname_ext);
krb5_free_context(context);
}
struct getargs args[] = {
{ "use-threads", 't', arg_flag, &use_threads, NULL, NULL },
{ "help", 'h', arg_flag, &help_flag, NULL, NULL },
{ "version", 0, arg_flag, &version_flag, NULL, NULL }
};
static int num_args = sizeof(args) / sizeof(args[0]);
int
main(int argc, char **argv)
{
char stemplate[sizeof("sqlite:testhdb-XXXXXX")];
#ifdef HAVE_LMDB
char ltemplate[sizeof("lmdb:testhdb-XXXXXX")];
#endif
int o = 0;
setprogname(argv[0]);
if (getarg(args, num_args, argc, argv, &o))
krb5_std_usage(1, args, num_args);
if (help_flag)
krb5_std_usage(0, args, num_args);
if (version_flag){
print_version(NULL);
return 0;
}
printf("Testing SQLite3 HDB backend\n");
memcpy(stemplate, "sqlite:testhdb-XXXXXX", sizeof("sqlite:testhdb-XXXXXX"));
test_hdb_concurrency(stemplate, "");
#ifdef HAVE_LMDB
printf("Testing LMDB HDB backend\n");
memcpy(ltemplate, "lmdb:testhdb-XXXXXX", sizeof("lmdb:testhdb-XXXXXX"));
test_hdb_concurrency(ltemplate, ".lmdb");
#endif
return 0;
}