From 69bc95847aee340178ac866b19159de7d68054e1 Mon Sep 17 00:00:00 2001
From: pavel-zotov <p519446@yandex.ru>
Date: Mon, 20 May 2024 13:07:39 +0300
Subject: [PATCH] Renamed file

---
 tests/bugs/gh_4723_all_nulls_test.py | 112 +++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 tests/bugs/gh_4723_all_nulls_test.py

diff --git a/tests/bugs/gh_4723_all_nulls_test.py b/tests/bugs/gh_4723_all_nulls_test.py
new file mode 100644
index 00000000..1d7ddda2
--- /dev/null
+++ b/tests/bugs/gh_4723_all_nulls_test.py
@@ -0,0 +1,112 @@
+#coding:utf-8
+
+"""
+ID:          issue-4723
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/4723
+TITLE:       Optimize the record-level RLE algorithm for a denser compression of shorter-than-declared strings and sets of subsequent NULLs [CORE4401]
+DESCRIPTION:
+    Test creates table with nullable varchar column an adds lot of rows with NULL value.
+    Then we run gstat in order to parse statistics related to data pages and avg fill ratio.
+    gstat reports for data pages and avg ratio following values:
+    4.0.5.3099:
+        Pointer pages: 2, data page slots: 2144
+        Data pages: 2144, average fill: 91%
+    5.0.1.1399, 6.0.0.351:
+        Pointer pages: 1, data page slots: 208
+        Data pages: 208, average fill: 46%
+    Test assumes that values returned for 5.x will not be change in too wide range for several upcoming years
+    in any order - see MIN_* and MAX_* thresholds.
+NOTES:
+    [20.05.2024] pzotov
+    Improvement URL (27-sep-2022 15:16):
+    https://github.com/FirebirdSQL/firebird/commit/54f1990b98d3e510a10d06fe9ceb76456804da52
+    Improved record compression (denser encoding of repeating bytes and less blocks) (#7302)
+
+    NB: snapshots that were just before and after this commit CAN NOT be verified:
+        5.0.0.745: raised BUGCHECK ("decompression overran buffer (179), file: sqz.cpp line: 293")
+        5.0.0.756: crashed
+    Checked on 5.0.1.1399, 6.0.0.351 for DB with page_size = 8192.
+"""
+import re
+
+import pytest
+import platform
+from firebird.qa import *
+
+N_ROWS = 30000
+N_WIDT = 32760
+
+MIN_DP_COUNT_THRESHOLD = 190
+MAX_DP_COUNT_THRESHOLD = 230
+MIN_AVG_FILL_THRESHOLD = 30
+MAX_AVG_FILL_THRESHOLD = 60
+
+init_ddl = f"""
+    recreate table test (f01 varchar({N_WIDT}));
+    commit;
+
+    set term ^;
+    execute block as
+        declare n int = {N_ROWS};
+    begin
+        while (n > 0) do
+        begin
+            insert into test(f01) values(null);
+            n = n - 1;
+        end
+    end
+    ^
+    set term ;^
+    commit;
+"""
+
+db = db_factory(page_size = 8192, init = init_ddl)
+act = python_act('db')
+
+@pytest.mark.version('>=5.0')
+def test_1(act: Action, capsys):
+
+    act.gstat(switches=['-d','-t', 'TEST', '-user', act.db.user, '-pass', act.db.password])
+
+    # 4.x: Pointer pages: 2, data page slots: 2144
+    # 5.x: Pointer pages: 1, data page slots: 208
+    p_pointer_pages_data_pages_slots = re.compile( r'Pointer\s+pages(:)?\s+\d+(,)?\s+data\s+page\s+slots(:)?\s+\d+' )
+
+    # Data pages: 208, average fill: 46%
+    p_data_pages_average_fill_ratio = re.compile( r'Data\s+pages(:)?\s+\d+(,)?\s+average\s+fill(:)?\s+\d+%' )
+
+    data_pages_cnt = avg_fill_ratio = -1
+    gstat_lines = act.stdout.splitlines()
+    for line in gstat_lines:
+        #print(line)
+        if p_pointer_pages_data_pages_slots.search(line):
+            data_pages_cnt = int(line.split()[-1])
+        if p_data_pages_average_fill_ratio.search(line):
+            avg_fill_ratio =  int(line.split()[-1].replace('%',''))
+
+
+    data_pages_cnt_expected_msg = f'data_pages_cnt: expected, within {MIN_DP_COUNT_THRESHOLD=} ... {MAX_DP_COUNT_THRESHOLD=}'
+    avg_fill_ratio_expected_msg = f'avg_fill_ratio: expected, within {MIN_AVG_FILL_THRESHOLD=} ... {MAX_AVG_FILL_THRESHOLD=}'
+    if data_pages_cnt > 0 and avg_fill_ratio > 0:
+        if data_pages_cnt >= MIN_DP_COUNT_THRESHOLD and data_pages_cnt <= MAX_DP_COUNT_THRESHOLD:
+            print(data_pages_cnt_expected_msg)
+        else:
+            print(f'data_pages_cnt UNEXPECTED: {data_pages_cnt=} -- out of scope: {MIN_DP_COUNT_THRESHOLD=} ... {MAX_DP_COUNT_THRESHOLD=}')
+
+        if avg_fill_ratio >= MIN_AVG_FILL_THRESHOLD and avg_fill_ratio <= MAX_AVG_FILL_THRESHOLD:
+            print(avg_fill_ratio_expected_msg)
+        else:
+            print(f'avg_fill_ratio UNEXPECTED: {avg_fill_ratio=} -- out of scope: {MIN_AVG_FILL_THRESHOLD=} ... {MAX_AVG_FILL_THRESHOLD=}')
+    else:
+        print(f'ERROR: at least one of: {data_pages_cnt=}, {avg_fill_ratio=} is INVALID.')
+        print('Could not properly parse gstat output:')
+        for p in gstat_lines:
+            print(p)
+
+    act.expected_stdout = f"""
+        {data_pages_cnt_expected_msg}
+        {avg_fill_ratio_expected_msg}
+    """
+    act.stdout = capsys.readouterr().out
+    assert act.clean_stdout == act.clean_expected_stdout
+