fix of crazy problems in SQLITE when two instances of database are running at a time

8 files changed, 90 insertions, 206 deletions

diff --git a/plugins/Dbx_sqlite/src/dbcontacts.cpp b/plugins/Dbx_sqlite/src/dbcontacts.cpp
index 0fb15f7082..bd012ee4c8 100755
--- a/plugins/Dbx_sqlite/src/dbcontacts.cpp
+++ b/plugins/Dbx_sqlite/src/dbcontacts.cpp
@@ -1,29 +1,7 @@
 #include "stdafx.h"
 
-enum {
-	SQL_CTC_STMT_COUNT = 0,
-	SQL_CTC_STMT_ADD,
-	SQL_CTC_STMT_DELETE,
-	SQL_CTC_STMT_DELETESETTINGS,
-	SQL_CTC_STMT_DELETEEVENTS,
-	SQL_CTC_STMT_DELETEEVENTS_SRT,
-};
-
-static CQuery ctc_stmts[] =
-{
-	{ "SELECT COUNT(1) FROM contacts LIMIT 1;" },
-	{ "INSERT INTO contacts VALUES (null);" },
-	{ "DELETE FROM contacts WHERE id = ?;" },
-	{ "DELETE FROM settings WHERE contact_id = ?;" },
-	{ "DELETE FROM events WHERE contact_id = ?;" },
-	{ "DELETE FROM events_srt WHERE contact_id = ?;" },
-};
-
 void CDbxSQLite::InitContacts()
 {
-	for (auto &it : ctc_stmts)
-		sqlite3_prepare_v3(m_db, it.szQuery, -1, SQLITE_PREPARE_PERSISTENT, &it.pQuery, nullptr);
-
 	sqlite3_stmt *stmt = nullptr;
 	sqlite3_prepare_v2(m_db, "SELECT contacts.id, COUNT(es.id) FROM contacts LEFT JOIN events_srt es ON es.contact_id = contacts.id GROUP BY contacts.id;", -1, &stmt, nullptr);
 	int rc = 0;
@@ -36,16 +14,10 @@ void CDbxSQLite::InitContacts()
 	sqlite3_finalize(stmt);
 }
 
-void CDbxSQLite::UninitContacts()
-{
-	for (auto &it : ctc_stmts)
-		sqlite3_finalize(it.pQuery);
-}
-
 LONG CDbxSQLite::GetContactCount()
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = ctc_stmts[SQL_CTC_STMT_COUNT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT COUNT(1) FROM contacts LIMIT 1;", qCntCount);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
 	int count = sqlite3_column_int(stmt, 0);
@@ -58,7 +30,7 @@ MCONTACT CDbxSQLite::AddContact()
 	MCONTACT hContact = INVALID_CONTACT_ID;
 	{
 		mir_cslock lock(m_csDbAccess);
-		sqlite3_stmt *stmt = ctc_stmts[SQL_CTC_STMT_ADD].pQuery;
+		sqlite3_stmt *stmt = InitQuery("INSERT INTO contacts VALUES (null);", qCntAdd);
 		int rc = sqlite3_step(stmt);
 		logError(rc, __FILE__, __LINE__);
 		sqlite3_reset(stmt);
@@ -90,7 +62,7 @@ LONG CDbxSQLite::DeleteContact(MCONTACT hContact)
 
 	mir_cslockfull lock(m_csDbAccess);
 
-	sqlite3_stmt *stmt = ctc_stmts[SQL_CTC_STMT_DELETEEVENTS].pQuery;
+	sqlite3_stmt *stmt = InitQuery("DELETE FROM events WHERE contact_id = ?;", qCntDelEvents);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -98,7 +70,7 @@ LONG CDbxSQLite::DeleteContact(MCONTACT hContact)
 	if (rc != SQLITE_DONE)
 		return 1;
 
-	stmt = ctc_stmts[SQL_CTC_STMT_DELETEEVENTS_SRT].pQuery;
+	stmt = InitQuery("DELETE FROM events_srt WHERE contact_id = ?;", qCntDelEventSrt);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -106,7 +78,7 @@ LONG CDbxSQLite::DeleteContact(MCONTACT hContact)
 	if (rc != SQLITE_DONE)
 		return 1;
 
-	stmt = ctc_stmts[SQL_CTC_STMT_DELETESETTINGS].pQuery;
+	stmt = InitQuery("DELETE FROM settings WHERE contact_id = ?;", qCntDelSettings);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -114,7 +86,7 @@ LONG CDbxSQLite::DeleteContact(MCONTACT hContact)
 	if (rc != SQLITE_DONE)
 		return 1;
 
-	stmt = ctc_stmts[SQL_CTC_STMT_DELETE].pQuery;
+	stmt = InitQuery("DELETE FROM contacts WHERE id = ?;", qCntDel);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
diff --git a/plugins/Dbx_sqlite/src/dbcrypt.cpp b/plugins/Dbx_sqlite/src/dbcrypt.cpp
index 86f74505d8..5eee3f3c70 100644
--- a/plugins/Dbx_sqlite/src/dbcrypt.cpp
+++ b/plugins/Dbx_sqlite/src/dbcrypt.cpp
@@ -1,29 +1,5 @@
 #include "stdafx.h"
 
-enum
-{
-	SQL_CRYPT_GET_MODE,
-	SQL_CRYPT_SET_MODE,
-	SQL_CRYPT_GET_PROVIDER,
-	SQL_CRYPT_SET_PROVIDER,
-	SQL_CRYPT_GET_KEY,
-	SQL_CRYPT_SET_KEY,
-	SQL_CRYPT_ENCRYPT,
-	SQL_CRYPT_ENCRYPT2,
-};
-
-static CQuery crypto_stmts[] =
-{
-	{ "SELECT data FROM crypto WHERE id=1;" },          // SQL_CRYPT_GET_MODE
-	{ "REPLACE INTO crypto VALUES (1, ?);" },           // SQL_CRYPT_SET_MODE 
-	{ "SELECT data FROM crypto WHERE id=2;" },          // SQL_CRYPT_GET_PROVIDER
-	{ "REPLACE INTO crypto VALUES(2, ?);" },            // SQL_CRYPT_SET_PROVIDER 
-	{ "SELECT data FROM crypto WHERE id=3;" },          // SQL_CRYPT_GET_KEY 
-	{ "REPLACE INTO crypto VALUES(3, ?);" },            // SQL_CRYPT_SET_KEY
-	{ "UPDATE events SET flags=?, data=? WHERE id=?;"}, // SQL_CRYPT_ENCRYPT
-	{ "UPDATE settings SET type=?, value=? WHERE contact_id=? AND module=? AND setting=?;"}, // SQL_CRYPT_ENCRYPT2
-};
-
 static char szCreateQuery[] =
 	"CREATE TABLE crypto (id INTEGER NOT NULL PRIMARY KEY, data ANY NOT NULL);\r\n"
 	"INSERT INTO crypto VALUES (1, 0), (2, 'AES (Rjindale)'), (3, (SELECT value FROM settings WHERE contact_id=0 AND module='CryptoEngine' AND setting='StoredKey'));\r\n"
@@ -34,15 +10,6 @@ void CDbxSQLite::InitEncryption()
 	int rc = sqlite3_exec(m_db, "SELECT COUNT(1) FROM crypto;", nullptr, nullptr, nullptr);
 	if (rc == SQLITE_ERROR) // table doesn't exist, fill it with existing data
 		sqlite3_exec(m_db, szCreateQuery, nullptr, nullptr, nullptr);
-
-	for (auto &it : crypto_stmts)
-		sqlite3_prepare_v3(m_db, it.szQuery, -1, SQLITE_PREPARE_PERSISTENT, &it.pQuery, nullptr);
-}
-
-void CDbxSQLite::UninintEncryption()
-{
-	for (auto &it : crypto_stmts)
-		sqlite3_finalize(it.pQuery);
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////
@@ -51,7 +18,7 @@ void CDbxSQLite::UninintEncryption()
 STDMETHODIMP_(BOOL) CDbxSQLite::ReadCryptoKey(MBinBuffer &buf)
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = crypto_stmts[SQL_CRYPT_GET_KEY].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT data FROM crypto WHERE id=3;", qCryptGetKey);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
 	if (rc != SQLITE_ROW) {
@@ -71,7 +38,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::StoreCryptoKey()
 	m_crypto->getKey(pKey, iKeyLength);
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = crypto_stmts[SQL_CRYPT_SET_KEY].pQuery;
+	sqlite3_stmt *stmt = InitQuery("REPLACE INTO crypto VALUES(3, ?);", qCryptSetKey);
 	sqlite3_bind_blob(stmt, 1, pKey, (int)iKeyLength, nullptr);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -88,7 +55,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::StoreCryptoKey()
 STDMETHODIMP_(BOOL) CDbxSQLite::ReadEncryption()
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = crypto_stmts[SQL_CRYPT_GET_MODE].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT data FROM crypto WHERE id=1;", qCryptGetMode);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
 	if (rc != SQLITE_ROW) {
@@ -107,7 +74,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::ReadEncryption()
 STDMETHODIMP_(CRYPTO_PROVIDER*) CDbxSQLite::ReadProvider()
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = crypto_stmts[SQL_CRYPT_GET_PROVIDER].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT data FROM crypto WHERE id=2;", qCryptGetProvider);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
 	sqlite3_reset(stmt);
@@ -117,7 +84,7 @@ STDMETHODIMP_(CRYPTO_PROVIDER*) CDbxSQLite::ReadProvider()
 STDMETHODIMP_(BOOL) CDbxSQLite::StoreProvider(CRYPTO_PROVIDER *pProvider)
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = crypto_stmts[SQL_CRYPT_SET_PROVIDER].pQuery;
+	sqlite3_stmt *stmt = InitQuery("REPLACE INTO crypto VALUES(2, ?);", qCryptSetProvider);
 	sqlite3_bind_text(stmt, 1, pProvider->pszName, (int)strlen(pProvider->pszName), 0);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -162,7 +129,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::EnableEncryption(BOOL bEncrypt)
 			dwFlags |= DBEF_ENCRYPTED;
 		}
 
-		sqlite3_stmt *upd = crypto_stmts[SQL_CRYPT_ENCRYPT].pQuery;
+		sqlite3_stmt *upd = InitQuery("UPDATE events SET flags=?, data=? WHERE id=?;", qCryptEnc1);
 		sqlite3_bind_int(upd, 1, dwFlags);
 		sqlite3_bind_blob(upd, 2, pNewBlob, (int)nNewBlob, 0);
 		sqlite3_bind_int(upd, 3, id);
@@ -186,7 +153,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::EnableEncryption(BOOL bEncrypt)
 		if (!bEncrypt && IsSettingEncrypted(pszModule, pszSetting))
 			continue;
 
-		sqlite3_stmt *upd = crypto_stmts[SQL_CRYPT_ENCRYPT2].pQuery;
+		sqlite3_stmt *upd = InitQuery("UPDATE settings SET type=?, value=? WHERE contact_id=? AND module=? AND setting=?;", qCryptEnc2);
 		sqlite3_bind_int(upd, 1, (bEncrypt) ? DBVT_ENCRYPTED : DBVT_UTF8);
 
 		size_t resultLen;
@@ -209,7 +176,7 @@ STDMETHODIMP_(BOOL) CDbxSQLite::EnableEncryption(BOOL bEncrypt)
 	}
 
 	// Finally update flag
-	stmt = crypto_stmts[SQL_CRYPT_SET_MODE].pQuery;
+	stmt = InitQuery("REPLACE INTO crypto VALUES (1, ?);", qCryptSetKey);
 	sqlite3_bind_int(stmt, 1, bEncrypt);
 	rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
diff --git a/plugins/Dbx_sqlite/src/dbevents.cpp b/plugins/Dbx_sqlite/src/dbevents.cpp
index 8a64af8046..b277bbbfbc 100755
--- a/plugins/Dbx_sqlite/src/dbevents.cpp
+++ b/plugins/Dbx_sqlite/src/dbevents.cpp
@@ -1,66 +1,16 @@
 #include "stdafx.h"
 
-enum {
-	SQL_EVT_STMT_COUNT = 0,
-	SQL_EVT_STMT_ADDEVENT,
-	SQL_EVT_STMT_DELETE,
-	SQL_EVT_STMT_EDIT,
-	SQL_EVT_STMT_BLOBSIZE,
-	SQL_EVT_STMT_GET,
-	SQL_EVT_STMT_GETFLAGS,
-	SQL_EVT_STMT_SETFLAGS,
-	SQL_EVT_STMT_GETCONTACT,
-	SQL_EVT_STMT_FINDFIRST,
-	SQL_EVT_STMT_FINDNEXT,
-	SQL_EVT_STMT_FINDLAST,
-	SQL_EVT_STMT_FINDPREV,
-	SQL_EVT_STMT_FINDFIRSTUNREAD,
-	SQL_EVT_STMT_GETIDBYSRVID,
-	SQL_EVT_STMT_ADDEVENT_SRT,
-	SQL_EVT_STMT_DELETE_SRT,
-	SQL_EVT_STMT_META_SPLIT,
-	SQL_EVT_STMT_META_MERGE_SELECT,
-};
-
 //TODO: hide it inside cursor class
-static const char* normal_order_query = 
-	"SELECT id FROM events_srt WHERE contact_id = ? ORDER BY timestamp, id;";
-static const char* normal_order_pos_query =
-	"SELECT id FROM events_srt WHERE contact_id = ? AND id >= ? ORDER BY timestamp, id;";
+static const char normal_order_query[] = "SELECT id FROM events_srt WHERE contact_id = ? ORDER BY timestamp, id;";
+static const char normal_order_pos_query[] = "SELECT id FROM events_srt WHERE contact_id = ? AND id >= ? ORDER BY timestamp, id;";
 
-static const char* reverse_order_query =
-	"SELECT id FROM events_srt WHERE contact_id = ? ORDER BY timestamp desc, id DESC;";
-static const char* reverse_order_pos_query =
-	"SELECT id FROM events_srt WHERE contact_id = ? AND id <= ? ORDER BY timestamp desc, id DESC;";
+static const char reverse_order_query[] = "SELECT id FROM events_srt WHERE contact_id = ? ORDER BY timestamp desc, id DESC;";
+static const char reverse_order_pos_query[] = "SELECT id FROM events_srt WHERE contact_id = ? AND id <= ? ORDER BY timestamp desc, id DESC;";
 
-static CQuery evt_stmts[] =
-{
-	{ "SELECT COUNT(1) FROM events_srt WHERE contact_id = ? LIMIT 1;" },                                                    // SQL_EVT_STMT_COUNT 
-	{ "INSERT INTO events(contact_id, module, timestamp, type, flags, data, server_id) VALUES (?, ?, ?, ?, ?, ?, ?);" },    // SQL_EVT_STMT_ADDEVENT
-	{ "DELETE FROM events WHERE id = ?;" },                                                                                 // SQL_EVT_STMT_DELETE
-	{ "UPDATE events SET module = ?, timestamp = ?, type = ?, flags = ?, data = ? WHERE id = ?;" },                         // SQL_EVT_STMT_EDIT
-	{ "SELECT LENGTH(data) FROM events WHERE id = ? LIMIT 1;" },                                                            // SQL_EVT_STMT_BLOBSIZE
-	{ "SELECT module, timestamp, type, flags, length(data), data FROM events WHERE id = ? LIMIT 1;" },                      // SQL_EVT_STMT_GET
-	{ "SELECT flags FROM events WHERE id = ? LIMIT 1;" },                                                                   // SQL_EVT_STMT_GETFLAGS
-	{ "UPDATE events SET flags = ? WHERE id = ?;" },                                                                        // SQL_EVT_STMT_SETFLAGS
-	{ "SELECT contact_id FROM events WHERE id = ? LIMIT 1;" },                                                              // SQL_EVT_STMT_GETCONTACT
-	{ normal_order_query },                                                                                                 // SQL_EVT_STMT_FINDFIRST
-	{ "SELECT id FROM events_srt WHERE contact_id = ? AND id > ? ORDER BY timestamp, id;" },                                // SQL_EVT_STMT_FINDNEXT
-	{ reverse_order_query },                                                                                                // SQL_EVT_STMT_FINDLAST
-	{ "SELECT id FROM events_srt WHERE contact_id = ? AND id < ? ORDER BY timestamp desc, id DESC;" },                      // SQL_EVT_STMT_FINDPREV
-	{ "SELECT id, timestamp FROM events WHERE contact_id = ? AND (flags & ?) = 0 ORDER BY timestamp, id LIMIT 1;" },        // SQL_EVT_STMT_FINDFIRSTUNREAD
-	{ "SELECT id, timestamp FROM events WHERE module = ? AND server_id = ? LIMIT 1;" },                                     // SQL_EVT_STMT_GETIDBYSRVID
-	{ "INSERT INTO events_srt(id, contact_id, timestamp) VALUES (?, ?, ?);" },                                              // SQL_EVT_STMT_ADDEVENT_SRT
-	{ "DELETE FROM events_srt WHERE id = ?;" },                                                                             // SQL_EVT_STMT_DELETE_SRT
-	{ "DELETE FROM events_srt WHERE contact_id = ?;" },                                                                     // SQL_EVT_STMT_META_SPLIT
-	{ "SELECT id, timestamp FROM events WHERE contact_id = ?;" },                                                           // SQL_EVT_STMT_META_MERGE_SELECT
-};
+static const char add_event_sort_query[] = "INSERT INTO events_srt(id, contact_id, timestamp) VALUES (?, ?, ?);";
 
 void CDbxSQLite::InitEvents()
 {
-	for (auto &it : evt_stmts)
-		sqlite3_prepare_v3(m_db, it.szQuery, -1, SQLITE_PREPARE_PERSISTENT, &it.pQuery, nullptr);
-
 	sqlite3_stmt *stmt = nullptr;
 	sqlite3_prepare_v2(m_db, "SELECT DISTINCT module FROM events;", -1, &stmt, nullptr);
 	int rc = 0;
@@ -78,9 +28,6 @@ void CDbxSQLite::UninitEvents()
 	for (auto &module : m_modules)
 		mir_free(module);
 	m_modules.destroy();
-
-	for (auto &it : evt_stmts)
-		sqlite3_finalize(it.pQuery);
 }
 
 LONG CDbxSQLite::GetEventCount(MCONTACT hContact)
@@ -90,7 +37,7 @@ LONG CDbxSQLite::GetEventCount(MCONTACT hContact)
 		return cc->m_count;
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_COUNT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT COUNT(1) FROM events_srt WHERE contact_id = ? LIMIT 1;", qEvCount);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -154,7 +101,7 @@ MEVENT CDbxSQLite::AddEvent(MCONTACT hContact, const DBEVENTINFO *dbei)
 	}
 
 	mir_cslockfull lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_ADDEVENT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("INSERT INTO events(contact_id, module, timestamp, type, flags, data, server_id) VALUES (?, ?, ?, ?, ?, ?, ?);", qEvAdd);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	sqlite3_bind_text(stmt, 2, tmp.szModule, (int)mir_strlen(tmp.szModule), nullptr);
 	sqlite3_bind_int64(stmt, 3, tmp.timestamp);
@@ -168,7 +115,7 @@ MEVENT CDbxSQLite::AddEvent(MCONTACT hContact, const DBEVENTINFO *dbei)
 
 	MEVENT hDbEvent = sqlite3_last_insert_rowid(m_db);
 
-	stmt = evt_stmts[SQL_EVT_STMT_ADDEVENT_SRT].pQuery;
+	stmt = InitQuery(add_event_sort_query, qEvAddSrt);
 	sqlite3_bind_int64(stmt, 1, hDbEvent);
 	sqlite3_bind_int64(stmt, 2, cc->contactID);
 	sqlite3_bind_int64(stmt, 3, tmp.timestamp);
@@ -178,7 +125,7 @@ MEVENT CDbxSQLite::AddEvent(MCONTACT hContact, const DBEVENTINFO *dbei)
 
 	cc->AddEvent(hDbEvent, tmp.timestamp, !tmp.markedRead());
 	if (ccSub != nullptr) {
-		stmt = evt_stmts[SQL_EVT_STMT_ADDEVENT_SRT].pQuery;
+		stmt = InitQuery(add_event_sort_query, qEvAddSrt);
 		sqlite3_bind_int64(stmt, 1, hDbEvent);
 		sqlite3_bind_int64(stmt, 2, ccSub->contactID);
 		sqlite3_bind_int64(stmt, 3, tmp.timestamp);
@@ -213,7 +160,7 @@ BOOL CDbxSQLite::DeleteEvent(MEVENT hDbEvent)
 		return 1;
 
 	mir_cslockfull lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_DELETE].pQuery;
+	sqlite3_stmt *stmt = InitQuery("DELETE FROM events WHERE id = ?;", qEvDel);
 	sqlite3_bind_int64(stmt, 1, hDbEvent);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -221,7 +168,7 @@ BOOL CDbxSQLite::DeleteEvent(MEVENT hDbEvent)
 	if (rc != SQLITE_DONE)
 		return 1;
 
-	stmt = evt_stmts[SQL_EVT_STMT_DELETE_SRT].pQuery;
+	stmt = InitQuery("DELETE FROM events_srt WHERE id = ?;", qEvDelSrt);
 	sqlite3_bind_int64(stmt, 1, hDbEvent);
 	rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -265,7 +212,7 @@ BOOL CDbxSQLite::EditEvent(MCONTACT hContact, MEVENT hDbEvent, const DBEVENTINFO
 	}
 
 	mir_cslockfull lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_EDIT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("UPDATE events SET module = ?, timestamp = ?, type = ?, flags = ?, data = ? WHERE id = ?;", qEvEdit);
 	sqlite3_bind_text(stmt, 1, tmp.szModule, (int)mir_strlen(tmp.szModule), nullptr);
 	sqlite3_bind_int64(stmt, 2, tmp.timestamp);
 	sqlite3_bind_int(stmt, 3, tmp.eventType);
@@ -297,7 +244,7 @@ LONG CDbxSQLite::GetBlobSize(MEVENT hDbEvent)
 		return -1;
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_BLOBSIZE].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT LENGTH(data) FROM events WHERE id = ? LIMIT 1;", qEvBlobSize);
 	sqlite3_bind_int(stmt, 1, hDbEvent);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -325,7 +272,7 @@ BOOL CDbxSQLite::GetEvent(MEVENT hDbEvent, DBEVENTINFO *dbei)
 	}
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_GET].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT module, timestamp, type, flags, length(data), data FROM events WHERE id = ? LIMIT 1;", qEvGet);
 	sqlite3_bind_int64(stmt, 1, hDbEvent);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -380,7 +327,7 @@ BOOL CDbxSQLite::MarkEventRead(MCONTACT hContact, MEVENT hDbEvent)
 	DWORD flags = 0;
 	{
 		mir_cslock lock(m_csDbAccess);
-		sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_GETFLAGS].pQuery;
+		sqlite3_stmt *stmt = InitQuery("SELECT flags FROM events WHERE id = ? LIMIT 1;", qEvGetFlags);
 		sqlite3_bind_int64(stmt, 1, hDbEvent);
 		int rc = sqlite3_step(stmt);
 		logError(rc, __FILE__, __LINE__);
@@ -398,7 +345,7 @@ BOOL CDbxSQLite::MarkEventRead(MCONTACT hContact, MEVENT hDbEvent)
 	flags |= DBEF_READ;
 	{
 		mir_cslock lock(m_csDbAccess);
-		sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_SETFLAGS].pQuery;
+		sqlite3_stmt *stmt = InitQuery("UPDATE events SET flags = ? WHERE id = ?;", qEvSetFlags);
 		sqlite3_bind_int(stmt, 1, flags);
 		sqlite3_bind_int64(stmt, 2, hDbEvent);
 		int rc = sqlite3_step(stmt);
@@ -423,7 +370,7 @@ MCONTACT CDbxSQLite::GetEventContact(MEVENT hDbEvent)
 		return INVALID_CONTACT_ID;
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_GETCONTACT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT contact_id FROM events WHERE id = ? LIMIT 1;", qEvGetContact);
 	sqlite3_bind_int64(stmt, 1, hDbEvent);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -474,7 +421,7 @@ MEVENT CDbxSQLite::FindFirstUnreadEvent(MCONTACT hContact)
 		return cc->m_unread;
 	}
 
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_FINDFIRSTUNREAD].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT id, timestamp FROM events WHERE contact_id = ? AND (flags & ?) = 0 ORDER BY timestamp, id LIMIT 1;", qEvFindUnread);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	sqlite3_bind_int(stmt, 2, DBEF_READ | DBEF_SENT);
 	int rc = sqlite3_step(stmt);
@@ -504,7 +451,7 @@ MEVENT CDbxSQLite::FindFirstEvent(MCONTACT hContact)
 		sqlite3_reset(fwd.cur);
 
 	fwd.hContact = hContact;
-	fwd.cur = evt_stmts[SQL_EVT_STMT_FINDFIRST].pQuery;
+	fwd.cur = InitQuery(normal_order_query, qEvFindFirst);
 	sqlite3_bind_int64(fwd.cur, 1, hContact);
 
 	int rc = sqlite3_step(fwd.cur);
@@ -530,7 +477,7 @@ MEVENT CDbxSQLite::FindNextEvent(MCONTACT hContact, MEVENT hDbEvent)
 			sqlite3_reset(fwd.cur);
 
 		fwd.hContact = hContact;
-		fwd.cur = evt_stmts[SQL_EVT_STMT_FINDNEXT].pQuery;
+		fwd.cur = InitQuery("SELECT id FROM events_srt WHERE contact_id = ? AND id > ? ORDER BY timestamp, id;", qEvFindNext);
 		sqlite3_bind_int64(fwd.cur, 1, hContact);
 		sqlite3_bind_int64(fwd.cur, 2, hDbEvent);
 	}
@@ -560,7 +507,7 @@ MEVENT CDbxSQLite::FindLastEvent(MCONTACT hContact)
 		sqlite3_reset(back.cur);
 
 	back.hContact = hContact;
-	back.cur = evt_stmts[SQL_EVT_STMT_FINDLAST].pQuery;
+	back.cur = InitQuery(reverse_order_query, qEvFindLast);
 	sqlite3_bind_int64(back.cur, 1, hContact);
 	int rc = sqlite3_step(back.cur);
 	logError(rc, __FILE__, __LINE__);
@@ -586,7 +533,7 @@ MEVENT CDbxSQLite::FindPrevEvent(MCONTACT hContact, MEVENT hDbEvent)
 			sqlite3_reset(back.cur);
 
 		back.hContact = hContact;
-		back.cur = evt_stmts[SQL_EVT_STMT_FINDPREV].pQuery;
+		back.cur = InitQuery("SELECT id FROM events_srt WHERE contact_id = ? AND id < ? ORDER BY timestamp desc, id DESC;", qEvFindPrev);
 		sqlite3_bind_int64(back.cur, 1, hContact);
 		sqlite3_bind_int64(back.cur, 2, hDbEvent);
 	}
@@ -608,12 +555,12 @@ BOOL CDbxSQLite::MetaMergeHistory(DBCachedContact *ccMeta, DBCachedContact *ccSu
 {
 	//TODO: test this
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_META_MERGE_SELECT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT id, timestamp FROM events WHERE contact_id = ?;", qEvMetaMerge);
 	sqlite3_bind_int64(stmt, 1, ccSub->contactID);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
 	while (rc == SQLITE_ROW) {
-		sqlite3_stmt *stmt2 = evt_stmts[SQL_EVT_STMT_ADDEVENT_SRT].pQuery;
+		sqlite3_stmt *stmt2 = InitQuery(add_event_sort_query, qEvAddSrt);
 		sqlite3_bind_int64(stmt2, 1, sqlite3_column_int64(stmt, 0));
 		sqlite3_bind_int64(stmt2, 2, ccMeta->contactID);
 		sqlite3_bind_int64(stmt2, 3, sqlite3_column_int64(stmt, 1));
@@ -632,7 +579,7 @@ BOOL CDbxSQLite::MetaMergeHistory(DBCachedContact *ccMeta, DBCachedContact *ccSu
 BOOL CDbxSQLite::MetaSplitHistory(DBCachedContact *ccMeta, DBCachedContact *)
 {
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_META_SPLIT].pQuery;
+	sqlite3_stmt *stmt = InitQuery("DELETE FROM events_srt WHERE contact_id = ?;", qEvMetaSplit);
 	sqlite3_bind_int64(stmt, 1, ccMeta->contactID);
 	int rc = sqlite3_step(stmt);
 	logError(rc, __FILE__, __LINE__);
@@ -653,7 +600,7 @@ MEVENT CDbxSQLite::GetEventById(LPCSTR szModule, LPCSTR szId)
 		return 0;
 
 	mir_cslock lock(m_csDbAccess);
-	sqlite3_stmt *stmt = evt_stmts[SQL_EVT_STMT_GETIDBYSRVID].pQuery;
+	sqlite3_stmt *stmt = InitQuery("SELECT id, timestamp FROM events WHERE module = ? AND server_id = ? LIMIT 1;", qEvGetById);
 	sqlite3_bind_text(stmt, 1, szModule, (int)mir_strlen(szModule), nullptr);
 	sqlite3_bind_text(stmt, 2, szId, (int)mir_strlen(szId), nullptr);
 	int rc = sqlite3_step(stmt);
diff --git a/plugins/Dbx_sqlite/src/dbintf.cpp b/plugins/Dbx_sqlite/src/dbintf.cpp
index 6fd1c9b6a1..1ae2834f1e 100755
--- a/plugins/Dbx_sqlite/src/dbintf.cpp
+++ b/plugins/Dbx_sqlite/src/dbintf.cpp
@@ -12,16 +12,15 @@ CDbxSQLite::CDbxSQLite(const wchar_t *pwszFileName, bool bReadOnly, bool bShared
 
 CDbxSQLite::~CDbxSQLite()
 {
-	int rc = sqlite3_exec(m_db, "commit;", nullptr, nullptr, nullptr);
-	logError(rc, __FILE__, __LINE__);
+	if (m_bTranStarted) {
+		int rc = sqlite3_exec(m_db, "commit;", nullptr, nullptr, nullptr);
+		logError(rc, __FILE__, __LINE__);
+	}
 
 	UninitEvents();
-	UninitContacts();
-	UninitSettings();
-	UninintEncryption();
 
 	if (m_db) {
-		rc = sqlite3_close(m_db);
+		int rc = sqlite3_close(m_db);
 		logError(rc, __FILE__, __LINE__);
 
 		m_db = nullptr;
@@ -43,7 +42,7 @@ int CDbxSQLite::Create()
 	rc = sqlite3_exec(m_db, "CREATE TABLE contacts (id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT);", nullptr, nullptr, nullptr);
 	logError(rc, __FILE__, __LINE__);
 
-	rc = sqlite3_exec(m_db, "CREATE TABLE crypto (id INTEGER NOT NULL PRIMARY KEY, data ANY NOT NULL);", nullptr, nullptr, nullptr);
+	rc = sqlite3_exec(m_db, "CREATE TABLE crypto (id INTEGER NOT NULL PRIMARY KEY, data NOT NULL);", nullptr, nullptr, nullptr);
 	logError(rc, __FILE__, __LINE__);
 
 	rc = sqlite3_exec(m_db, "CREATE TABLE events (id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, contact_id INTEGER NOT NULL, module TEXT NOT NULL,"
@@ -60,7 +59,7 @@ int CDbxSQLite::Create()
 	rc = sqlite3_exec(m_db, "CREATE TABLE events_srt (id INTEGER NOT NULL, contact_id INTEGER NOT NULL, timestamp INTEGER, PRIMARY KEY(contact_id, timestamp, id));", nullptr, nullptr, nullptr);
 	logError(rc, __FILE__, __LINE__);
 
-	rc = sqlite3_exec(m_db, "CREATE TABLE settings (contact_id INTEGER NOT NULL, module TEXT NOT NULL, setting TEXT NOT NULL, type INTEGER NOT NULL, value ANY,"
+	rc = sqlite3_exec(m_db, "CREATE TABLE settings (contact_id INTEGER NOT NULL, module TEXT NOT NULL, setting TEXT NOT NULL, type INTEGER NOT NULL, value NOT NULL,"
 		"PRIMARY KEY(contact_id, module, setting)) WITHOUT ROWID;", nullptr, nullptr, nullptr);
 	logError(rc, __FILE__, __LINE__);
 
@@ -146,6 +145,7 @@ int CDbxSQLite::Load()
 	if (InitCrypt())
 		return EGROKPRF_CANTREAD;
 
+	m_bTranStarted = true;
 	rc = sqlite3_exec(m_db, "begin transaction;", nullptr, nullptr, nullptr);
 	logError(rc, __FILE__, __LINE__);
 	return EGROKPRF_NOERROR;
diff --git a/plugins/Dbx_sqlite/src/dbintf.h b/plugins/Dbx_sqlite/src/dbintf.h
index a2a2fbcaf5..6e772eb6ef 100755
--- a/plugins/Dbx_sqlite/src/dbintf.h
+++ b/plugins/Dbx_sqlite/src/dbintf.h
@@ -4,6 +4,13 @@
 
 #include <m_db_int.h>
 
+struct CQuery
+{
+	~CQuery();
+
+	sqlite3_stmt *pQuery = nullptr;
+};
+
 struct DBCachedContact : public DBCachedContactBase
 {
 	int32_t  m_count;
@@ -72,22 +79,29 @@ class CDbxSQLite : public MDatabaseCommon, public MZeroedObject
 		}
 	} m_impl;
 
-	bool m_safetyMode, m_bReadOnly, m_bShared;
+	bool m_safetyMode, m_bReadOnly, m_bShared, m_bTranStarted;
 
+	// contacts
 	void InitContacts();
-	void UninitContacts();
+	CQuery qCntCount, qCntAdd, qCntDel, qCntDelSettings, qCntDelEvents, qCntDelEventSrt;
 
+	// encryption
+	void InitEncryption();
+	CQuery qCryptGetMode, qCryptSetMode, qCryptGetProvider, qCryptSetProvider, qCryptGetKey, qCryptSetKey, qCryptEnc1, qCryptEnc2;
+
+	// events
 	LIST<char> m_modules;
 	void InitEvents();
 	void UninitEvents();
+	CQuery qEvCount, qEvAdd, qEvDel, qEvEdit, qEvBlobSize, qEvGet, qEvGetFlags, qEvSetFlags, qEvGetContact;
+	CQuery qEvFindFirst, qEvFindNext, qEvFindLast, qEvFindPrev, qEvFindUnread, qEvGetById, qEvAddSrt, qEvDelSrt, qEvMetaSplit, qEvMetaMerge;
 
+	// settings
 	void InitSettings();
-	void UninitSettings();
-
-	void InitEncryption();
-	void UninintEncryption();
+	CQuery qSettModules, qSettWrite, qSettDel, qSettEnum, qSettChanges;
 
 	void DBFlush(bool bForce = false);
+	sqlite3_stmt* InitQuery(const char *szQuery, CQuery &stmt);
 
 public:
 	CDbxSQLite(const wchar_t *pwszFileName, bool bReadOnly, bool bShared);
diff --git a/plugins/Dbx_sqlite/src/dbsettings.cpp b/plugins/Dbx_sqlite/src/dbsettings.cpp
index bc00dbb918..65fcd75aae 100755
--- a/plugins/Dbx_sqlite/src/dbsettings.cpp
+++ b/plugins/Dbx_sqlite/src/dbsettings.cpp
@@ -1,29 +1,7 @@
 #include "stdafx.h"
 
-enum {
-	SQL_SET_STMT_ENUM = 0,
-	SQL_SET_STMT_GET,
-	SQL_SET_STMT_REPLACE,
-	SQL_SET_STMT_DELETE,
-	SQL_SET_STMT_ENUMMODULE,
-	SQL_SET_STMT_CHANGES
-};
-
-static CQuery settings_stmts[] =
-{
-	{ "SELECT DISTINCT module FROM settings;" },
-	{ "SELECT type, value FROM settings WHERE contact_id = ? AND module = ? AND setting = ? LIMIT 1;" },
-	{ "REPLACE INTO settings(contact_id, module, setting, type, value) VALUES (?, ?, ?, ?, ?);" },
-	{ "DELETE FROM settings WHERE contact_id = ? AND module = ? AND setting = ?;" },
-	{ "SELECT setting FROM settings WHERE contact_id = ? AND module = ?;" },
-	{ "SELECT CHANGES() FROM settings;" },
-};
-
 void CDbxSQLite::InitSettings()
 {
-	for (auto &it : settings_stmts)
-		sqlite3_prepare_v3(m_db, it.szQuery, -1, SQLITE_PREPARE_PERSISTENT, &it.pQuery, nullptr);
-
 	sqlite3_stmt *stmt = nullptr;
 	sqlite3_prepare_v2(m_db, "SELECT type, value, contact_id, module, setting FROM settings;", -1, &stmt, nullptr);
 	while (sqlite3_step(stmt) == SQLITE_ROW) {
@@ -82,11 +60,6 @@ void CDbxSQLite::InitSettings()
 	FillContactSettings();
 }
 
-void CDbxSQLite::UninitSettings()
-{
-	for (auto &it : settings_stmts)
-		sqlite3_finalize(it.pQuery);
-}
 
 /////////////////////////////////////////////////////////////////////////////////////////
 
@@ -94,7 +67,7 @@ BOOL CDbxSQLite::EnumModuleNames(DBMODULEENUMPROC pFunc, void *param)
 {
 	LIST<char> modules(100);
 	{
-		sqlite3_stmt *stmt = settings_stmts[SQL_SET_STMT_ENUM].pQuery;
+		sqlite3_stmt *stmt = InitQuery("SELECT DISTINCT module FROM settings;", qSettModules);
 		int rc = 0;
 		while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
 			const char *value = (const char *)sqlite3_column_text(stmt, 0);
@@ -116,7 +89,7 @@ BOOL CDbxSQLite::EnumModuleNames(DBMODULEENUMPROC pFunc, void *param)
 
 BOOL CDbxSQLite::WriteContactSettingWorker(MCONTACT hContact, DBCONTACTWRITESETTING &dbcws)
 {
-	sqlite3_stmt *stmt = settings_stmts[SQL_SET_STMT_REPLACE].pQuery;
+	sqlite3_stmt *stmt = InitQuery("REPLACE INTO settings(contact_id, module, setting, type, value) VALUES (?, ?, ?, ?, ?);", qSettWrite);
 	sqlite3_bind_int64(stmt, 1, hContact);
 	sqlite3_bind_text(stmt, 2, dbcws.szModule, (int)mir_strlen(dbcws.szModule), nullptr);
 	sqlite3_bind_text(stmt, 3, dbcws.szSetting, (int)mir_strlen(dbcws.szSetting), nullptr);
@@ -167,14 +140,15 @@ BOOL CDbxSQLite::DeleteContactSetting(MCONTACT hContact, LPCSTR szModule, LPCSTR
 	char *szCachedSettingName = m_cache->GetCachedSetting(szModule, szSetting, mir_strlen(szModule), mir_strlen(szSetting));
 	if (szCachedSettingName[-1] == 0) { // it's not a resident variable
 		mir_cslock lock(m_csDbAccess);
-		sqlite3_stmt *stmt = settings_stmts[SQL_SET_STMT_DELETE].pQuery;
+		sqlite3_stmt *stmt = InitQuery("DELETE FROM settings WHERE contact_id = ? AND module = ? AND setting = ?;", qSettDel);
 		sqlite3_bind_int64(stmt, 1, hContact);
 		sqlite3_bind_text(stmt, 2, szModule, (int)mir_strlen(szModule), nullptr);
 		sqlite3_bind_text(stmt, 3, szSetting, (int)mir_strlen(szSetting), nullptr);
 		int rc = sqlite3_step(stmt);
 		logError(rc, __FILE__, __LINE__);
 		sqlite3_reset(stmt);
-		stmt = settings_stmts[SQL_SET_STMT_CHANGES].pQuery;
+
+		stmt = InitQuery("SELECT CHANGES() FROM settings;", qSettChanges);
 		rc = sqlite3_step(stmt);
 		logError(rc, __FILE__, __LINE__);
 		int deleted = sqlite3_column_int(stmt, 0);
@@ -212,7 +186,7 @@ BOOL CDbxSQLite::EnumContactSettings(MCONTACT hContact, DBSETTINGENUMPROC pfnEnu
 	LIST<char> settings(100);
 	{
 		mir_cslock lock(m_csDbAccess);
-		sqlite3_stmt *stmt = settings_stmts[SQL_SET_STMT_ENUMMODULE].pQuery;
+		sqlite3_stmt *stmt = InitQuery("SELECT setting FROM settings WHERE contact_id = ? AND module = ?;", qSettEnum);
 		sqlite3_bind_int64(stmt, 1, hContact);
 		sqlite3_bind_text(stmt, 2, szModule, (int)mir_strlen(szModule), nullptr);
 		int rc = 0;
diff --git a/plugins/Dbx_sqlite/src/stdafx.h b/plugins/Dbx_sqlite/src/stdafx.h
index 6d8fc14a1d..9b8cc30a59 100644
--- a/plugins/Dbx_sqlite/src/stdafx.h
+++ b/plugins/Dbx_sqlite/src/stdafx.h
@@ -21,12 +21,6 @@
 #include "resource.h"
 #include "version.h"
 
-struct CQuery
-{
-	const char *szQuery;
-	sqlite3_stmt *pQuery;
-};
-
 void logError(int rc, const char *szFile, int line);
 
 /////////////////////////////////////////////////////////////////////////////////////////
diff --git a/plugins/Dbx_sqlite/src/utils.cpp b/plugins/Dbx_sqlite/src/utils.cpp
index 174fe9d394..89f03b6d93 100644
--- a/plugins/Dbx_sqlite/src/utils.cpp
+++ b/plugins/Dbx_sqlite/src/utils.cpp
@@ -12,3 +12,19 @@ void logError(int rc, const char *szFile, int line)
 	_ASSERT(rc == 0);
 	Netlib_Logf(0, "SQLITE error %d (%s, %d)", rc, szFile, line);
 }
+
+/////////////////////////////////////////////////////////////////////////////////////////
+
+sqlite3_stmt* CDbxSQLite::InitQuery(const char *szQuery, CQuery &stmt)
+{
+	if (stmt.pQuery == nullptr) 
+		sqlite3_prepare_v3(m_db, szQuery, -1, SQLITE_PREPARE_PERSISTENT, &stmt.pQuery, nullptr);
+
+	return stmt.pQuery;
+}
+
+CQuery::~CQuery()
+{
+	if (pQuery)
+		sqlite3_finalize(pQuery);
+}