src/db.c: integrate SQLite3 with talloc allocator

This change introduces an optional feature that allows to make
SQLite3 use talloc for all internal allocations. This would
facilitate finding memleaks. OsmoHLR needs to be configured
with '--enable-sqlite-talloc'.

  full talloc report on 'OsmoHLR' (total 292168 bytes in 449 blocks)
    struct osmo_gsup_server        contains    162 bytes in   3 blocks (ref 0)
      ...
    struct db_context              contains 288407 bytes in 420 blocks (ref 0)
      hlr.db                       contains      7 bytes in   1 blocks (ref 0)
    SQLite3                        contains 288192 bytes in 418 blocks (ref 0)
      db.c:95                      contains     48 bytes in   1 blocks (ref 0)
      db.c:95                      contains      2 bytes in   1 blocks (ref 0)
      ...

Unfortunately, old SQLite3 versions (such as 3.8.2) run out
of memory when trying to initialize a new database:

  DDB ERROR  db.c:88 (7) statement aborts at 3: []
  DDB ERROR  db.c:420 Unable to set Write-Ahead Logging: out of memory
  DDB ERROR  db.c:88 (7) statement aborts at 3: []
  DDB ERROR  db.c:238 Unable to prepare SQL statement
             'SELECT name FROM sqlite_master WHERE type='table' AND name=?'
  ...

I've noticed a huge difference in heap usage footprint compared to
generic malloc. At the same time, the recent versions (at least
3.24.0), work just fine.

Change-Id: Icfe67ed0f063b63e6794f9516da3003d01cf20a7

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/db/Makefile.am b/tests/db/Makefile.am
index fa925f8..5730937 100644
--- a/tests/db/Makefile.am
+++ b/tests/db/Makefile.am
@@ -36,6 +36,10 @@ db_test_LDADD = \
 	$(SQLITE3_LIBS) \
 	$(NULL)
 
+if DB_SQLITE_DEBUG
+db_test_LDADD += $(top_builddir)/src/db_debug.o
+endif
+
 .PHONY: db_test.db update_exp manual manual-nonverbose manual-gdb
 db_test.db:
 	rm -f db_test.db