diff --git a/include/smax-postgres.h b/include/smax-postgres.h
index 746b489..0d93806 100644
--- a/include/smax-postgres.h
+++ b/include/smax-postgres.h
@@ -101,14 +101,14 @@
 #define SMAXPQ_VERSION_STRING str_2(SMAXPQ_MAJOR_VERSION) "." str_2(SMAXPQ_MINOR_VERSION) \
                                   "." str_2(SMAXPQ_PATCHLEVEL) SMAXPQ_RELEASE_STRING
 
-extern boolean debug;             ///< whether to show debug messages
+extern XBoolean debug;             ///< whether to show debug messages
 
 /**
  * A set of properties that determine how an SMA-X variable is logged into the PostgreSQL DB.
  */
 typedef struct {
-  boolean force;                  ///< Whether the variable should be logged no matter what other settings.
-  boolean exclude;                ///< Whether to exclude this variable from logging
+  XBoolean force;                  ///< Whether the variable should be logged no matter what other settings.
+  XBoolean exclude;                ///< Whether to exclude this variable from logging
   int sampling;                   ///< sampling step for array data (sampling every n values only)
 } logger_properties;
 
@@ -150,8 +150,8 @@ int setSQLUserName(const char *name);
 const char *getSQLAuth();
 int setSQLAuth(const char *passwd);
 
-boolean isUseHyperTables();
-void setUseHyperTables(boolean value);
+XBoolean isUseHyperTables();
+void setUseHyperTables(XBoolean value);
 
 int getUpdateInterval();
 int getSnapshotInterval();
diff --git a/src/logger-config.c b/src/logger-config.c
index 50cdf90..0a20193 100644
--- a/src/logger-config.c
+++ b/src/logger-config.c
@@ -48,7 +48,7 @@ static char *sqlServer;
 static char *dbName;
 static char *dbUser;
 static char *dbAuth;
-static boolean use_hyper_tables = FALSE;
+static XBoolean use_hyper_tables = FALSE;
 
 static int update_interval = MINUTE;    ///< (s) The rate of fast updates for changing variables (min. 1m).
 static int snapshot_interval = MINUTE;  ///< (s) The rate of snapshotting all variables (min. 1m).
@@ -426,7 +426,7 @@ logger_properties *getLogProperties(const char *id) {
  * @param updateTime  (s) UNIX timestamp when the variable was last updated in the SMA-X database.
  * @return            TRUE (1) if the variable should be logged into the SQL database, or else FALSE (0)
  */
-boolean isLogging(const char *id, double updateTime) {
+XBoolean isLogging(const char *id, double updateTime) {
   const logger_properties *p;
   const time_t now = time(NULL);
 
@@ -614,7 +614,7 @@ int setSQLAuth(const char *passwd) {
  *
  * @sa setUseHyperTables()
  */
-boolean isUseHyperTables() {
+XBoolean isUseHyperTables() {
   return use_hyper_tables;
 }
 
@@ -626,7 +626,7 @@ boolean isUseHyperTables() {
  *
  * @sa isUseHyperTables()
  */
-void setUseHyperTables(boolean value) {
+void setUseHyperTables(XBoolean value) {
   use_hyper_tables = (value != 0);
 }
 
diff --git a/src/postgres-backend.c b/src/postgres-backend.c
index 0695886..7e77824 100644
--- a/src/postgres-backend.c
+++ b/src/postgres-backend.c
@@ -71,7 +71,7 @@ typedef struct {
   int cols;                     ///< Number of array elements (columns)
   char sqlType[SQL_TYPE_LEN];   ///< The SQL storage type
 
-  boolean hasMeta;              ///< (boolean) if we have metadata available
+  XBoolean hasMeta;             ///< (boolean) if we have metadata available
   int metaVersion;              ///< metadata serial number
   int sampling;                 ///< the current sampling interval for array data
   int ndim;                     ///< array dimensions (may be 0 for scalars)
@@ -620,7 +620,7 @@ static size_t appendValue(const void *data, XType type, char *dst, size_t len) {
 
   switch (type) {
 
-    case X_BOOLEAN: return pos + x_snprintf(dst, len - pos, "%s",*(boolean *) data ? "true" : "false");
+    case X_BOOLEAN: return pos + x_snprintf(dst, len - pos, "%s",*(XBoolean *) data ? "true" : "false");
 
     case X_BYTE: return pos + x_snprintf(dst, len - pos, "%hhd", *(char *) data);
 
@@ -1010,6 +1010,7 @@ static int sqlCreateMetaTable(int id) {
 static int sqlAddMeta(const Variable *u, TableDescriptor *t) {
   const XField *f = &u->field;
   size_t l = 0;
+  struct tm tm = {};
   int step, ndim;
 
   if(!u || !t) {
@@ -1028,7 +1029,8 @@ static int sqlAddMeta(const Variable *u, TableDescriptor *t) {
   ensureCommandCapacity(200 + META_SHAPE_LEN + META_UNIT_LEN);
   l += x_snprintf(&cmd[l], cmdSize - l, "INSERT INTO " META_NAME_PATTERN " VALUES(DEFAULT" SQL_SEP, t->index);
 
-  l += strftime(&cmd[l], cmdSize - l, SQL_DATE_FORMAT, gmtime(&u->updateTime));
+  gmtime_r(&u->updateTime, &tm);
+  l += strftime(&cmd[l], cmdSize - l, SQL_DATE_FORMAT, &tm);
 
   l += x_snprintf(&cmd[l], cmdSize - l, SQL_SEP "%d", step);
   l += x_snprintf(&cmd[l], cmdSize - l, SQL_SEP "%d", ndim);
@@ -1108,7 +1110,7 @@ static int sqlGetLastMeta(TableDescriptor *t) {
 }
 
 
-static boolean isMetaUpdate(const Variable *u, const TableDescriptor *t) {
+static XBoolean isMetaUpdate(const Variable *u, const TableDescriptor *t) {
   const XField *f = &u->field;
   int i;
   int ndim = f->ndim;
@@ -1460,6 +1462,7 @@ static int sqlAddValues(const Variable *u) {
   TableDescriptor *t;
   int len;
   size_t pos = 0;
+  struct tm tm = {};
   char sqlType[SQL_TYPE_LEN];
 
   if(!u) {
@@ -1511,9 +1514,11 @@ static int sqlAddValues(const Variable *u) {
 
   ensureCommandCapacity(200 + SQL_TABLE_NAME_LEN + getSampleCount(u) * len);
 
+  gmtime_r(&u->grabTime, &tm);
+
   /* Now insert the data */
   pos += x_snprintf(&cmd[pos], cmdSize - pos, "INSERT INTO " TABLE_NAME_PATTERN " VALUES(", t->index);
-  pos += strftime(&cmd[pos], cmdSize - pos, SQL_DATE_FORMAT, gmtime(&u->grabTime));
+  pos += strftime(&cmd[pos], cmdSize - pos, SQL_DATE_FORMAT, &tm);
   pos += x_snprintf(&cmd[pos], cmdSize - pos, SQL_SEP "'%d'", (int) (u->grabTime - u->updateTime));
   pos += appendValues(u, &cmd[pos], cmdSize - pos);
 
@@ -1544,7 +1549,7 @@ static int sqlAddValues(const Variable *u) {
 }
 
 
-static boolean sqlDeleteVar(const char *id) {
+static XBoolean sqlDeleteVar(const char *id) {
   int tid, n = 0;
 
   if(!id) return FALSE;
diff --git a/src/smax-collector.c b/src/smax-collector.c
index 6c9e735..b8120c1 100644
--- a/src/smax-collector.c
+++ b/src/smax-collector.c
@@ -71,7 +71,7 @@ static void *GrabberThread(void *arg);
  * @return      X_SUCCESS (0) if successful or else an error code (<0).
  */
 int initCollector() {
-  static boolean warned;
+  static XBoolean warned;
 
   int i, status;
 
@@ -185,12 +185,12 @@ static void DestroyEntries(RedisEntry *entries, int n) {
  * @return      TRUE (1) if successfully queued a DB update for the variable, or else FALSE (0; errno may be
  *              set to indicate the type of error -- if any).
  */
-static boolean SubmitUpdate(Update *u) {
+static XBoolean SubmitUpdate(Update *u) {
   const XMeta *m;
   const logger_properties *p;
   Variable *v;
   XField *f;
-  boolean force = FALSE;
+  XBoolean force = FALSE;
 
   if(!u || !u->var) {
     errno = EINVAL;
@@ -546,7 +546,7 @@ static double GetServerTime() {
  *                          perform an incremental update of the variable that have changed since last time.
  * @return X_SUCCESS (0) or else an error code (<0)
  */
-static int Grab(VarGroup *group, const time_t grabTime, boolean isSnapshot) {
+static int Grab(VarGroup *group, const time_t grabTime, XBoolean isSnapshot) {
   double t = GetServerTime();
   int status;
 
@@ -594,7 +594,7 @@ static void *GrabberThread(void *arg) {
 
   for(;;) {
     time_t target = SleepToRound(getUpdateInterval());
-    boolean isSnapshot = FALSE;
+    XBoolean isSnapshot = FALSE;
     int i;
 
     if(getSnapshotInterval() > 0) isSnapshot = (target % getSnapshotInterval() < getUpdateInterval());
diff --git a/src/smax-postgres.c b/src/smax-postgres.c
index 7913c1a..567c2c9 100644
--- a/src/smax-postgres.c
+++ b/src/smax-postgres.c
@@ -22,7 +22,7 @@
 
 #include "smax-postgres.h"
 
-boolean debug = FALSE;
+XBoolean debug = FALSE;
 
 
 static void *CleanupThread(void *arg) {
@@ -66,7 +66,7 @@ int main(int argc, const char *argv[]) {
   char *configFile = SMAXPQ_DEFAULT_CONFIG;
   char *owner = "postgres";
   char *ownerPasswd = NULL;
-  boolean bootstrap = FALSE, version = FALSE;
+  XBoolean bootstrap = FALSE, version = FALSE;
   int c;
 
   const struct poptOption options[] = {