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Commit 2275d04

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michaelpqmichaelpq
committed
pageinspect: Fix handling of all-zero pages
Getting from get_raw_page() an all-zero page is considered as a valid case by the buffer manager and it can happen for example when finding a corrupted page with zero_damaged_pages enabled (using zero_damaged_pages to look at corrupted pages happens), or after a crash when a relation file is extended before any WAL for its new data is generated (before a vacuum or autovacuum job comes in to do some cleanup). However, all the functions of pageinspect, as of the index AMs (except hash that has its own idea of new pages), heap, the FSM or the page header have never worked with all-zero pages, causing various crashes when going through the page internals. This commit changes all the pageinspect functions to be compliant with all-zero pages, where the choice is made to return NULL or no rows for SRFs when finding a new page. get_raw_page() still works the same way, returning a batch of zeros in the bytea of the page retrieved. A hard error could be used but NULL, while more invasive, is useful when scanning relation files in full to get a batch of results for a single relation in one query. Tests are added for all the code paths impacted. Reported-by: Daria Lepikhova Author: Michael Paquier Discussion: https://postgr.es/m/561e187b-3549-c8d5-03f5-525c14e65bd0@postgrespro.ru Backpatch-through: 10
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15 files changed

+154
-0
lines changed

15 files changed

+154
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lines changed

‎contrib/pageinspect/brinfuncs.c

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -58,6 +58,9 @@ brin_page_type(PG_FUNCTION_ARGS)
5858

5959
page = get_page_from_raw(raw_page);
6060

61+
if (PageIsNew(page))
62+
PG_RETURN_NULL();
63+
6164
/* verify the special space has the expected size */
6265
if (PageGetSpecialSize(page) != MAXALIGN(sizeof(BrinSpecialSpace)))
6366
ereport(ERROR,
@@ -95,6 +98,9 @@ verify_brin_page(bytea *raw_page, uint16 type, const char *strtype)
9598
{
9699
Page page = get_page_from_raw(raw_page);
97100

101+
if (PageIsNew(page))
102+
return page;
103+
98104
/* verify the special space has the expected size */
99105
if (PageGetSpecialSize(page) != MAXALIGN(sizeof(BrinSpecialSpace)))
100106
ereport(ERROR,
@@ -182,6 +188,13 @@ brin_page_items(PG_FUNCTION_ARGS)
182188
/* minimally verify the page we got */
183189
page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, "regular");
184190

191+
if (PageIsNew(page))
192+
{
193+
brin_free_desc(bdesc);
194+
index_close(indexRel, AccessShareLock);
195+
PG_RETURN_NULL();
196+
}
197+
185198
/*
186199
* Initialize output functions for all indexed datatypes; simplifies
187200
* calling them later.
@@ -348,6 +361,9 @@ brin_metapage_info(PG_FUNCTION_ARGS)
348361

349362
page = verify_brin_page(raw_page, BRIN_PAGETYPE_META, "metapage");
350363

364+
if (PageIsNew(page))
365+
PG_RETURN_NULL();
366+
351367
/* Build a tuple descriptor for our result type */
352368
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
353369
elog(ERROR, "return type must be a row type");
@@ -399,6 +415,12 @@ brin_revmap_data(PG_FUNCTION_ARGS)
399415
/* minimally verify the page we got */
400416
page = verify_brin_page(raw_page, BRIN_PAGETYPE_REVMAP, "revmap");
401417

418+
if (PageIsNew(page))
419+
{
420+
MemoryContextSwitchTo(mctx);
421+
PG_RETURN_NULL();
422+
}
423+
402424
state = palloc(sizeof(*state));
403425
state->tids = ((RevmapContents *) PageGetContents(page))->rm_tids;
404426
state->idx = 0;

‎contrib/pageinspect/btreefuncs.c

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -545,6 +545,12 @@ bt_page_items_bytea(PG_FUNCTION_ARGS)
545545

546546
uargs->page = get_page_from_raw(raw_page);
547547

548+
if (PageIsNew(uargs->page))
549+
{
550+
MemoryContextSwitchTo(mctx);
551+
PG_RETURN_NULL();
552+
}
553+
548554
uargs->offset = FirstOffsetNumber;
549555

550556
/* verify the special space has the expected size */

‎contrib/pageinspect/expected/brin.out

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -62,4 +62,29 @@ ERROR: input page is not a valid BRIN page
6262
SELECT * FROM brin_revmap_data(get_raw_page('test1', 0));
6363
ERROR: input page is not a valid BRIN page
6464
\set VERBOSITY default
65+
-- Tests with all-zero pages.
66+
SHOW block_size \gset
67+
SELECT brin_page_type(decode(repeat('00', :block_size), 'hex'));
68+
brin_page_type
69+
----------------
70+
71+
(1 row)
72+
73+
SELECT brin_page_items(decode(repeat('00', :block_size), 'hex'), 'test1_a_idx');
74+
brin_page_items
75+
-----------------
76+
(0 rows)
77+
78+
SELECT brin_metapage_info(decode(repeat('00', :block_size), 'hex'));
79+
brin_metapage_info
80+
--------------------
81+
82+
(1 row)
83+
84+
SELECT brin_revmap_data(decode(repeat('00', :block_size), 'hex'));
85+
brin_revmap_data
86+
------------------
87+
88+
(1 row)
89+
6590
DROP TABLE test1;

‎contrib/pageinspect/expected/btree.out

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -93,4 +93,10 @@ ERROR: input page is not a valid btree page
9393
SELECT bt_page_items(get_raw_page('test1_a_brin', 0));
9494
ERROR: input page is not a valid btree page
9595
\set VERBOSITY default
96+
-- Tests with all-zero pages.
97+
SHOW block_size \gset
98+
SELECT bt_page_items(decode(repeat('00', :block_size), 'hex'));
99+
-[ RECORD 1 ]-+-
100+
bt_page_items |
101+
96102
DROP TABLE test1;

‎contrib/pageinspect/expected/gin.out

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -54,3 +54,17 @@ ERROR: input page is not a valid GIN data leaf page
5454
SELECT * FROM gin_leafpage_items(get_raw_page('test1', 0));
5555
ERROR: input page is not a valid GIN data leaf page
5656
\set VERBOSITY default
57+
-- Tests with all-zero pages.
58+
SHOW block_size \gset
59+
SELECT gin_leafpage_items(decode(repeat('00', :block_size), 'hex'));
60+
-[ RECORD 1 ]------+-
61+
gin_leafpage_items |
62+
63+
SELECT gin_metapage_info(decode(repeat('00', :block_size), 'hex'));
64+
-[ RECORD 1 ]-----+-
65+
gin_metapage_info |
66+
67+
SELECT gin_page_opaque_info(decode(repeat('00', :block_size), 'hex'));
68+
-[ RECORD 1 ]--------+-
69+
gin_page_opaque_info |
70+

‎contrib/pageinspect/expected/hash.out

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -186,4 +186,16 @@ ERROR: input page is not a valid hash page
186186
SELECT hash_page_type(get_raw_page('test_hash', 0));
187187
ERROR: input page is not a valid hash page
188188
\set VERBOSITY default
189+
-- Tests with all-zero pages.
190+
SHOW block_size \gset
191+
SELECT hash_metapage_info(decode(repeat('00', :block_size), 'hex'));
192+
ERROR: page is not a hash meta page
193+
SELECT hash_page_items(decode(repeat('00', :block_size), 'hex'));
194+
ERROR: page is not a hash bucket or overflow page
195+
SELECT hash_page_stats(decode(repeat('00', :block_size), 'hex'));
196+
ERROR: page is not a hash bucket or overflow page
197+
SELECT hash_page_type(decode(repeat('00', :block_size), 'hex'));
198+
-[ RECORD 1 ]--+-------
199+
hash_page_type | unused
200+
189201
DROP TABLE test_hash;

‎contrib/pageinspect/expected/page.out

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -212,3 +212,23 @@ ERROR: invalid page size
212212
SELECT page_header('ccc'::bytea);
213213
ERROR: invalid page size
214214
\set VERBOSITY default
215+
-- Tests with all-zero pages.
216+
SHOW block_size \gset
217+
SELECT fsm_page_contents(decode(repeat('00', :block_size), 'hex'));
218+
fsm_page_contents
219+
-------------------
220+
221+
(1 row)
222+
223+
SELECT page_header(decode(repeat('00', :block_size), 'hex'));
224+
page_header
225+
-----------------------
226+
(0/0,0,0,0,0,0,0,0,0)
227+
(1 row)
228+
229+
SELECT page_checksum(decode(repeat('00', :block_size), 'hex'), 1);
230+
page_checksum
231+
---------------
232+
233+
(1 row)
234+

‎contrib/pageinspect/fsmfuncs.c

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -46,6 +46,10 @@ fsm_page_contents(PG_FUNCTION_ARGS)
4646
errmsg("must be superuser to use raw page functions")));
4747

4848
page = get_page_from_raw(raw_page);
49+
50+
if (PageIsNew(page))
51+
PG_RETURN_NULL();
52+
4953
fsmpage = (FSMPage) PageGetContents(page);
5054

5155
initStringInfo(&sinfo);

‎contrib/pageinspect/ginfuncs.c

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -49,6 +49,9 @@ gin_metapage_info(PG_FUNCTION_ARGS)
4949

5050
page = get_page_from_raw(raw_page);
5151

52+
if (PageIsNew(page))
53+
PG_RETURN_NULL();
54+
5255
if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData)))
5356
ereport(ERROR,
5457
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -115,6 +118,9 @@ gin_page_opaque_info(PG_FUNCTION_ARGS)
115118

116119
page = get_page_from_raw(raw_page);
117120

121+
if (PageIsNew(page))
122+
PG_RETURN_NULL();
123+
118124
if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData)))
119125
ereport(ERROR,
120126
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -200,6 +206,12 @@ gin_leafpage_items(PG_FUNCTION_ARGS)
200206

201207
page = get_page_from_raw(raw_page);
202208

209+
if (PageIsNew(page))
210+
{
211+
MemoryContextSwitchTo(mctx);
212+
PG_RETURN_NULL();
213+
}
214+
203215
if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GinPageOpaqueData)))
204216
ereport(ERROR,
205217
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),

‎contrib/pageinspect/rawpage.c

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -296,5 +296,8 @@ page_checksum(PG_FUNCTION_ARGS)
296296

297297
page = get_page_from_raw(raw_page);
298298

299+
if (PageIsNew(page))
300+
PG_RETURN_NULL();
301+
299302
PG_RETURN_INT16(pg_checksum_page((char *) page, blkno));
300303
}

‎contrib/pageinspect/sql/brin.sql

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -27,4 +27,11 @@ SELECT * FROM brin_metapage_info(get_raw_page('test1', 0));
2727
SELECT * FROM brin_revmap_data(get_raw_page('test1', 0));
2828
\set VERBOSITY default
2929

30+
-- Tests with all-zero pages.
31+
SHOW block_size \gset
32+
SELECT brin_page_type(decode(repeat('00', :block_size), 'hex'));
33+
SELECT brin_page_items(decode(repeat('00', :block_size), 'hex'), 'test1_a_idx');
34+
SELECT brin_metapage_info(decode(repeat('00', :block_size), 'hex'));
35+
SELECT brin_revmap_data(decode(repeat('00', :block_size), 'hex'));
36+
3037
DROP TABLE test1;

‎contrib/pageinspect/sql/btree.sql

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -41,4 +41,8 @@ SELECT bt_page_items(get_raw_page('test1', 0));
4141
SELECT bt_page_items(get_raw_page('test1_a_brin', 0));
4242
\set VERBOSITY default
4343

44+
-- Tests with all-zero pages.
45+
SHOW block_size \gset
46+
SELECT bt_page_items(decode(repeat('00', :block_size), 'hex'));
47+
4448
DROP TABLE test1;

‎contrib/pageinspect/sql/gin.sql

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -31,3 +31,9 @@ SELECT * FROM gin_metapage_info(get_raw_page('test1', 0));
3131
SELECT * FROM gin_page_opaque_info(get_raw_page('test1', 0));
3232
SELECT * FROM gin_leafpage_items(get_raw_page('test1', 0));
3333
\set VERBOSITY default
34+
35+
-- Tests with all-zero pages.
36+
SHOW block_size \gset
37+
SELECT gin_leafpage_items(decode(repeat('00', :block_size), 'hex'));
38+
SELECT gin_metapage_info(decode(repeat('00', :block_size), 'hex'));
39+
SELECT gin_page_opaque_info(decode(repeat('00', :block_size), 'hex'));

‎contrib/pageinspect/sql/hash.sql

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -96,4 +96,11 @@ SELECT hash_page_stats(get_raw_page('test_hash', 0));
9696
SELECT hash_page_type(get_raw_page('test_hash', 0));
9797
\set VERBOSITY default
9898

99+
-- Tests with all-zero pages.
100+
SHOW block_size \gset
101+
SELECT hash_metapage_info(decode(repeat('00', :block_size), 'hex'));
102+
SELECT hash_page_items(decode(repeat('00', :block_size), 'hex'));
103+
SELECT hash_page_stats(decode(repeat('00', :block_size), 'hex'));
104+
SELECT hash_page_type(decode(repeat('00', :block_size), 'hex'));
105+
99106
DROP TABLE test_hash;

‎contrib/pageinspect/sql/page.sql

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -89,3 +89,9 @@ SELECT fsm_page_contents('aaa'::bytea);
8989
SELECT page_checksum('bbb'::bytea, 0);
9090
SELECT page_header('ccc'::bytea);
9191
\set VERBOSITY default
92+
93+
-- Tests with all-zero pages.
94+
SHOW block_size \gset
95+
SELECT fsm_page_contents(decode(repeat('00', :block_size), 'hex'));
96+
SELECT page_header(decode(repeat('00', :block_size), 'hex'));
97+
SELECT page_checksum(decode(repeat('00', :block_size), 'hex'), 1);

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