diff --git a/tests/bugs/gh_7854_test.py b/tests/bugs/gh_7854_test.py
new file mode 100644
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--- /dev/null
+++ b/tests/bugs/gh_7854_test.py
@@ -0,0 +1,154 @@
+#coding:utf-8
+
+"""
+ID:          issue-7854
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/7854
+TITLE:       Performance issue with time zones
+DESCRIPTION:
+    Test uses four SP with code based on example provided in the ticket:
+    https://github.com/FirebirdSQL/firebird/issues/7854#issuecomment-1817956235
+
+    Duration is measured as difference between psutil.Process(fb_pid).cpu_times() counters.
+    We do these measures <N_MEASURES> times for each SP, and each result is added to the list
+    which, in turn, is the source for median evaluation.
+    Finally, we get ratio between minimal and maximal medians (see 'median_ratio')
+    On Windows 8.1 usually this ratio is about 2.67 (before fix it was morte than 16).
+    
+    Test is considered as passed if median_ratio less than threshold <MAX_RATIO>.
+NOTES:
+    Checked on 6.0.0.139, 5.0.0.1277, 4.0.5.3031
+"""
+
+import psutil
+import pytest
+from firebird.qa import *
+
+#--------------------------------------------------------------------
+def median(lst):
+    n = len(lst)
+    s = sorted(lst)
+    return (sum(s[n//2-1:n//2+1])/2.0, s[n//2])[n % 2] if n else None
+#--------------------------------------------------------------------
+
+###########################
+###   S E T T I N G S   ###
+###########################
+
+# How many times we call procedures:
+N_MEASURES = 11
+
+# How many iterations must be done:
+N_COUNT_PER_MEASURE = 100000
+
+# Maximal value for ratio between maximal and minimal medians
+#
+MAX_RATIO = 5
+#############
+
+init_script = \
+f'''
+    set term ^;
+    create or alter procedure tz2ts (n_cnt int) as
+        declare ts timestamp;
+        declare tz timestamp with time zone;
+    begin
+        tz = current_timestamp;
+        while (n_cnt > 0) do
+        begin
+            ts = tz;
+            n_cnt = n_cnt - 1;
+        end
+    end
+    ^
+
+    create or alter procedure ts2tz (n_cnt int) as
+        declare ts timestamp;
+        declare tz timestamp with time zone;
+    begin
+        ts = localtime;
+        while (n_cnt > 0) do
+        begin
+            tz = ts;
+            n_cnt = n_cnt - 1;
+        end
+    end
+    ^
+
+    create or alter procedure ts2ts (n_cnt int) as
+        declare ts timestamp;
+        declare tx timestamp;
+    begin
+        ts = localtime;
+        while (n_cnt > 0) do
+        begin
+            tx = ts;
+            n_cnt = n_cnt - 1;
+        end
+    end
+    ^
+
+    create or alter procedure tz2tz (n_cnt int) as
+        declare tz timestamp with time zone;
+        declare tx timestamp with time zone;
+    begin
+        tz = current_timestamp;
+        while (n_cnt > 0) do
+        begin
+            tx = tz;
+            n_cnt = n_cnt - 1;
+        end
+    end
+    ^
+    commit
+    ^
+'''
+
+db = db_factory(init = init_script)
+act = python_act('db')
+
+expected_stdout = """
+    Medians ratio: acceptable
+"""
+
+@pytest.mark.version('>=4.0.5')
+def test_1(act: Action, capsys):
+    
+    with act.db.connect() as con:
+        cur=con.cursor()
+        cur.execute('select mon$server_pid as p from mon$attachments where mon$attachment_id = current_connection')
+        fb_pid = int(cur.fetchone()[0])
+
+        sp_time = {}
+        for i in range(0, N_MEASURES):
+            for sp_name in ('tz2ts', 'ts2tz', 'ts2ts', 'tz2tz'):
+                fb_info_init = psutil.Process(fb_pid).cpu_times()
+                cur.callproc( sp_name, (N_COUNT_PER_MEASURE,) )
+                fb_info_curr = psutil.Process(fb_pid).cpu_times()
+                sp_time[ sp_name, i ]  = max(fb_info_curr.user - fb_info_init.user, 0.000001)
+
+
+    tz2ts_median = median([v for k,v in sp_time.items() if k[0] == 'tz2ts'])
+    ts2tz_median = median([v for k,v in sp_time.items() if k[0] == 'ts2tz'])
+    ts2ts_median = median([v for k,v in sp_time.items() if k[0] == 'ts2ts'])
+    tz2tz_median = median([v for k,v in sp_time.items() if k[0] == 'tz2tz'])
+    #----------------------------------
+    max_median = max(tz2ts_median, ts2tz_median, ts2ts_median, tz2tz_median)
+    min_median = max(min(tz2ts_median, ts2tz_median, ts2ts_median, tz2tz_median), 0.000001)
+    median_ratio = max_median / min_median
+
+    print( 'Medians ratio: ' + ('acceptable' if median_ratio <= MAX_RATIO else '/* perf_issue_tag */ POOR: %s, more than threshold: %s' % ( '{:9g}'.format(median_ratio), '{:9g}'.format(MAX_RATIO) ) ) )
+    if median_ratio > MAX_RATIO:
+        print('CPU times for each of {N_MEASURES} measures:')
+        for k,v in sp_time.items():
+            print(k,':::',v)
+        print(f'Median cpu time for {N_MEASURES} measures using loops for {N_COUNT_PER_MEASURE} iterations in each SP call:')
+        print('tz2ts_median:',tz2ts_median)
+        print('ts2tz_median:',ts2tz_median)
+        print('ts2ts_median:',ts2ts_median)
+        print('tz2tz_median:',tz2tz_median)
+        print('max_median:', max_median)
+        print('min_median:', min_median)
+
+    act.expected_stdout = expected_stdout
+    act.stdout = capsys.readouterr().out
+    assert act.clean_stdout == act.clean_expected_stdout