switch sqlite3 to single-threaded mode

Looking at 'perf top' of osmo-msc under load shows that there's a
significant amount of time spent in terms of locking (mutex,...)
which is useless as osmo-msc is a single-threaded application.

Unfortunately libdbi doesn't provide a mechanism to perform
sqlite3_config(), so we have to do it directly here, introducing an
explicit build-time dependency (and linkage) to libsqlite3.

Related: OS#5559
Change-Id: I5bbea90d28b6d73b64b9e5124ff59304b90a8a75

configure.ac

@@ -36,6 +36,7 @@ if test "x$PKG_CONFIG_INSTALLED" = "xno"; then
 fi
 PKG_PROG_PKG_CONFIG([0.20])
 
+PKG_CHECK_MODULES(LIBSQLITE3, sqlite3)
 PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.6.0)
 PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty >= 1.6.0)
 PKG_CHECK_MODULES(LIBOSMOCTRL, libosmoctrl >= 1.6.0)

contrib/osmo-msc.spec.in

@@ -34,6 +34,7 @@ BuildRequires:  systemd-rpm-macros
 %endif
 BuildRequires:  pkgconfig >= 0.20
 BuildRequires:  pkgconfig(dbi)
+BuildRequires:  pkgconfig(sqlite3)
 BuildRequires:  pkgconfig(libcrypto) >= 0.9.5
 BuildRequires:  pkgconfig(libosmo-gsup-client) >= 1.4.0
 BuildRequires:  pkgconfig(libosmo-mgcp-client) >= 1.9.0

debian/control

@@ -11,6 +11,7 @@ Build-Depends: debhelper (>=9),
                pkg-config,
                libdbi-dev,
                libdbd-sqlite3,
+               libsqlite3-dev,
                libsctp-dev,
                libtalloc-dev,
                libsmpp34-dev (>= 1.14.0),

src/libmsc/db.c

@@ -28,6 +28,7 @@
 #include <string.h>
 #include <errno.h>
 #include <time.h>
+#include <sqlite3.h>
 #include <dbi/dbi.h>
 
 #include <osmocom/msc/gsm_data.h>
@@ -637,6 +638,8 @@ static int db_configure(void)
 
 int db_init(const char *name)
 {
+	sqlite3_config(SQLITE_CONFIG_SINGLETHREAD);
+
 	dbi_initialize_r(NULL, &inst);
 
 	LOGP(DDB, LOGL_NOTICE, "Init database connection to '%s' using %s\n",

src/osmo-msc/Makefile.am

@@ -19,6 +19,7 @@ AM_CFLAGS = \
 	$(LIBOSMOSIGTRAN_CFLAGS) \
 	$(LIBOSMOMGCPCLIENT_CFLAGS) \
 	$(LIBOSMOGSUPCLIENT_CFLAGS) \
+	$(LIBSQLITE3_CFLAGS) \
 	$(NULL)
 
 AM_LDFLAGS = \
@@ -48,6 +49,7 @@ osmo_msc_LDADD = \
 	$(LIBOSMOSIGTRAN_LIBS) \
 	$(LIBOSMOMGCPCLIENT_LIBS) \
 	$(LIBOSMOGSUPCLIENT_LIBS) \
+	$(LIBSQLITE3_LIBS) \
 	-ldbi \
 	-lsctp \
 	$(NULL)

tests/db_sms/Makefile.am

@@ -17,6 +17,7 @@ AM_CFLAGS = \
 	$(LIBSMPP34_CFLAGS) \
 	$(LIBOSMOMGCPCLIENT_CFLAGS) \
 	$(LIBOSMOGSUPCLIENT_CFLAGS) \
+	$(LIBSQLITE3_CFLAGS) \
 	$(NULL)
 
 EXTRA_DIST = \
@@ -46,6 +47,7 @@ db_sms_test_LDADD = \
 	$(LIBASN1C_LIBS) \
 	$(LIBOSMOMGCPCLIENT_LIBS) \
 	$(LIBOSMOGSUPCLIENT_LIBS) \
+	$(LIBSQLITE3_LIBS) \
 	$(LIBRARY_GSM) \
 	-ldbi \
 	$(NULL)

tests/msc_vlr/Makefile.am

@@ -17,6 +17,7 @@ AM_CFLAGS = \
 	$(LIBASN1C_CFLAGS) \
 	$(LIBOSMOMGCPCLIENT_CFLAGS) \
 	$(LIBOSMOGSUPCLIENT_CFLAGS) \
+	$(LIBSQLITE3_CFLAGS) \
 	$(NULL)
 
 AM_LDFLAGS = \
@@ -41,6 +42,7 @@ LDADD = \
 	$(LIBASN1C_LIBS) \
 	$(LIBOSMOMGCPCLIENT_LIBS) \
 	$(LIBOSMOGSUPCLIENT_LIBS) \
+	$(LIBSQLITE3_LIBS) \
 	$(LIBRARY_GSM) \
 	-ldbi \
 	$(NULL)

tests/sms_queue/Makefile.am

@@ -15,6 +15,7 @@ AM_CFLAGS = \
 	$(LIBASN1C_CFLAGS) \
 	$(LIBOSMOMGCPCLIENT_CFLAGS) \
 	$(LIBOSMOGSUPCLIENT_CFLAGS) \
+	$(LIBSQLITE3_CFLAGS) \
 	$(NULL)
 
 EXTRA_DIST = \
@@ -43,6 +44,7 @@ sms_queue_test_LDADD = \
 	$(LIBASN1C_LIBS) \
 	$(LIBOSMOMGCPCLIENT_LIBS) \
 	$(LIBOSMOGSUPCLIENT_LIBS) \
+	$(LIBSQLITE3_LIBS) \
 	$(LIBRARY_GSM) \
 	-ldbi \
 	$(NULL)