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pageinspect: Fix gist_page_items() with included columns 

Non-leaf pages of GiST indexes contain key attributes, leaf pages
contain both key and non-key attributes, and gist_page_items() ignored
the handling of non-key attributes.  This caused a few problems when
using gist_page_items() on a GiST index with INCLUDE:
- On a non-leaf page, the function would crash.
- On a leaf page, the function would work, but miss to display all the
values for included attributes.

This commit fixes gist_page_items() to handle such cases in a more
appropriate way, and now displays the values of key and non-key
attributes for each item separately in a style consistent with what
ruleutils.c would generate for the attribute list, depending on the page
type dealt with.  In a way similar to how a record is displayed, values
would be double-quoted for key or non-key attributes if required.

ruleutils.c did not provide a routine able to control if non-key
attributes should be displayed, so an extended() routine for index
definitions is added to work around the leaf and non-leaf page
differences.

While on it, this commit fixes a third problem related to the amount of
data reported for key attributes.  The code originally relied on
BuildIndexValueDescription() (used for error reports on constraints)
that would not print all the data stored in the index but the index
opclass's input type, so this limited the amount of information
available.  This switch makes gist_page_items() much cheaper as there is
no need to run ACL checks for each item printed, which is not an issue
anyway as superuser rights are required to execute the functions of
pageinspect.  Opclasses whose data cannot be displayed can rely on
gist_page_items_bytea().

The documentation of this function was slightly incorrect for the
output results generated on HEAD and v15, so adjust it on these
branches.

Author: Alexander Lakhin, Michael Paquier
Discussion: https://postgr.es/m/17884-cb8c326522977acb@postgresql.org
Backpatch-through: 14
This commit is contained in:
Michael Paquier 2023-05-19 12:37:58 +09:00
parent 613a7eca9c
commit e7bff46e50
6 changed files with 178 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
contrib/pageinspect/expected/gist.out
View File

@ -31,24 +31,24 @@ SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
COMMIT;
SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
itemoffset | ctid | itemlen | dead | keys
------------+-----------+---------+------+-------------------
1 | (1,65535) | 40 | f | (p)=((185,185))
2 | (2,65535) | 40 | f | (p)=((370,370))
3 | (3,65535) | 40 | f | (p)=((555,555))
4 | (4,65535) | 40 | f | (p)=((740,740))
5 | (5,65535) | 40 | f | (p)=((870,870))
6 | (6,65535) | 40 | f | (p)=((1000,1000))
itemoffset | ctid | itemlen | dead | keys
------------+-----------+---------+------+-------------------------------
1 | (1,65535) | 40 | f | (p)=("(185,185),(1,1)")
2 | (2,65535) | 40 | f | (p)=("(370,370),(186,186)")
3 | (3,65535) | 40 | f | (p)=("(555,555),(371,371)")
4 | (4,65535) | 40 | f | (p)=("(740,740),(556,556)")
5 | (5,65535) | 40 | f | (p)=("(870,870),(741,741)")
6 | (6,65535) | 40 | f | (p)=("(1000,1000),(871,871)")
(6 rows)
SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;
itemoffset | ctid | itemlen | dead | keys
------------+-------+---------+------+-------------
1 | (0,1) | 40 | f | (p)=((1,1))
2 | (0,2) | 40 | f | (p)=((2,2))
3 | (0,3) | 40 | f | (p)=((3,3))
4 | (0,4) | 40 | f | (p)=((4,4))
5 | (0,5) | 40 | f | (p)=((5,5))
itemoffset | ctid | itemlen | dead | keys
------------+-------+---------+------+---------------------
1 | (0,1) | 40 | f | (p)=("(1,1),(1,1)")
2 | (0,2) | 40 | f | (p)=("(2,2),(2,2)")
3 | (0,3) | 40 | f | (p)=("(3,3),(3,3)")
4 | (0,4) | 40 | f | (p)=("(4,4),(4,4)")
5 | (0,5) | 40 | f | (p)=("(5,5),(5,5)")
(5 rows)
-- gist_page_items_bytea prints the raw key data as a bytea. The output of that is
@ -107,4 +107,27 @@ SELECT gist_page_opaque_info(decode(repeat('00', :block_size), 'hex'));
(1 row)
-- Test gist_page_items with included columns.
-- Non-leaf pages contain only the key attributes, and leaf pages contain
-- the included attributes.
ALTER TABLE test_gist ADD COLUMN i int DEFAULT NULL;
CREATE INDEX test_gist_idx_inc ON test_gist
USING gist (p) INCLUDE (t, i);
-- Mask the value of the key attribute to avoid alignment issues.
SELECT regexp_replace(keys, '\(p\)=\("(.*?)"\)', '(p)=("<val>")') AS keys_nonleaf_1
FROM gist_page_items(get_raw_page('test_gist_idx_inc', 0), 'test_gist_idx_inc')
WHERE itemoffset = 1;
keys_nonleaf_1
----------------
(p)=("<val>")
(1 row)
SELECT keys AS keys_leaf_1
FROM gist_page_items(get_raw_page('test_gist_idx_inc', 1), 'test_gist_idx_inc')
WHERE itemoffset = 1;
keys_leaf_1
------------------------------------------------------
(p) INCLUDE (t, i)=("(1,1),(1,1)") INCLUDE (1, null)
(1 row)
DROP TABLE test_gist;

102
contrib/pageinspect/gistfuncs.c
View File

@ -21,8 +21,10 @@
#include "storage/itemptr.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/rel.h"
#include "utils/pg_lsn.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/ruleutils.h"
#include "utils/varlena.h"
PG_FUNCTION_INFO_V1(gist_page_opaque_info);
@ -198,9 +200,13 @@ gist_page_items(PG_FUNCTION_ARGS)
Oid indexRelid = PG_GETARG_OID(1);
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
Relation indexRel;
TupleDesc tupdesc;
Page page;
uint16 flagbits;
bits16 printflags = 0;
OffsetNumber offset;
OffsetNumber maxoff = InvalidOffsetNumber;
char *index_columns;
if (!superuser())
ereport(ERROR,
@ -226,6 +232,27 @@ gist_page_items(PG_FUNCTION_ARGS)
PG_RETURN_NULL();
}
flagbits = GistPageGetOpaque(page)->flags;
/*
* Included attributes are added when dealing with leaf pages, discarded
* for non-leaf pages as these include only data for key attributes.
*/
printflags |= RULE_INDEXDEF_PRETTY;
if (flagbits & F_LEAF)
{
tupdesc = RelationGetDescr(indexRel);
}
else
{
tupdesc = CreateTupleDescCopy(RelationGetDescr(indexRel));
tupdesc->natts = IndexRelationGetNumberOfKeyAttributes(indexRel);
printflags |= RULE_INDEXDEF_KEYS_ONLY;
}
index_columns = pg_get_indexdef_columns_extended(indexRelid,
printflags);
/* Avoid bogus PageGetMaxOffsetNumber() call with deleted pages */
if (GistPageIsDeleted(page))
elog(NOTICE, "page is deleted");
@ -242,7 +269,8 @@ gist_page_items(PG_FUNCTION_ARGS)
IndexTuple itup;
Datum itup_values[INDEX_MAX_KEYS];
bool itup_isnull[INDEX_MAX_KEYS];
char *key_desc;
StringInfoData buf;
int i;
id = PageGetItemId(page, offset);
@ -251,7 +279,7 @@ gist_page_items(PG_FUNCTION_ARGS)
itup = (IndexTuple) PageGetItem(page, id);
index_deform_tuple(itup, RelationGetDescr(indexRel),
index_deform_tuple(itup, tupdesc,
itup_values, itup_isnull);
memset(nulls, 0, sizeof(nulls));
@ -261,9 +289,71 @@ gist_page_items(PG_FUNCTION_ARGS)
values[2] = Int32GetDatum((int) IndexTupleSize(itup));
values[3] = BoolGetDatum(ItemIdIsDead(id));
key_desc = BuildIndexValueDescription(indexRel, itup_values, itup_isnull);
if (key_desc)
values[4] = CStringGetTextDatum(key_desc);
if (index_columns)
{
initStringInfo(&buf);
appendStringInfo(&buf, "(%s)=(", index_columns);
/* Most of this is copied from record_out(). */
for (i = 0; i < tupdesc->natts; i++)
{
char *value;
char *tmp;
bool nq = false;
if (itup_isnull[i])
value = "null";
else
{
Oid foutoid;
bool typisvarlena;
Oid typoid;
typoid = tupdesc->attrs[i].atttypid;
getTypeOutputInfo(typoid, &foutoid, &typisvarlena);
value = OidOutputFunctionCall(foutoid, itup_values[i]);
}
if (i == IndexRelationGetNumberOfKeyAttributes(indexRel))
appendStringInfoString(&buf, ") INCLUDE (");
else if (i > 0)
appendStringInfoString(&buf, ", ");
/* Check whether we need double quotes for this value */
nq = (value[0] == '\0'); /* force quotes for empty string */
for (tmp = value; *tmp; tmp++)
{
char ch = *tmp;
if (ch == '"' || ch == '\\' ||
ch == '(' || ch == ')' || ch == ',' ||
isspace((unsigned char) ch))
{
nq = true;
break;
}
}
/* And emit the string */
if (nq)
appendStringInfoCharMacro(&buf, '"');
for (tmp = value; *tmp; tmp++)
{
char ch = *tmp;
if (ch == '"' || ch == '\\')
appendStringInfoCharMacro(&buf, ch);
appendStringInfoCharMacro(&buf, ch);
}
if (nq)
appendStringInfoCharMacro(&buf, '"');
}
appendStringInfoChar(&buf, ')');
values[4] = CStringGetTextDatum(buf.data);
nulls[4] = false;
}
else
{
values[4] = (Datum) 0;

14
contrib/pageinspect/sql/gist.sql
View File

@ -52,4 +52,18 @@ SELECT gist_page_items_bytea(decode(repeat('00', :block_size), 'hex'));
SELECT gist_page_items(decode(repeat('00', :block_size), 'hex'), 'test_gist_idx'::regclass);
SELECT gist_page_opaque_info(decode(repeat('00', :block_size), 'hex'));
-- Test gist_page_items with included columns.
-- Non-leaf pages contain only the key attributes, and leaf pages contain
-- the included attributes.
ALTER TABLE test_gist ADD COLUMN i int DEFAULT NULL;
CREATE INDEX test_gist_idx_inc ON test_gist
USING gist (p) INCLUDE (t, i);
-- Mask the value of the key attribute to avoid alignment issues.
SELECT regexp_replace(keys, '\(p\)=\("(.*?)"\)', '(p)=("<val>")') AS keys_nonleaf_1
FROM gist_page_items(get_raw_page('test_gist_idx_inc', 0), 'test_gist_idx_inc')
WHERE itemoffset = 1;
SELECT keys AS keys_leaf_1
FROM gist_page_items(get_raw_page('test_gist_idx_inc', 1), 'test_gist_idx_inc')
WHERE itemoffset = 1;
DROP TABLE test_gist;

19
doc/src/sgml/pageinspect.sgml
View File

@ -764,16 +764,15 @@ test=# SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
the data stored in a page of a <acronym>GiST</acronym> index. For example:
<screen>
test=# SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
itemoffset | ctid | itemlen | dead | keys
------------+-----------+---------+------+-------------------
1 | (1,65535) | 40 | f | (p)=((166,166))
2 | (2,65535) | 40 | f | (p)=((332,332))
3 | (3,65535) | 40 | f | (p)=((498,498))
4 | (4,65535) | 40 | f | (p)=((664,664))
5 | (5,65535) | 40 | f | (p)=((830,830))
6 | (6,65535) | 40 | f | (p)=((996,996))
7 | (7,65535) | 40 | f | (p)=((1000,1000))
(7 rows)
itemoffset | ctid | itemlen | dead | keys
------------+-----------+---------+------+-------------------------------
1 | (1,65535) | 40 | f | (p)=("(185,185),(1,1)")
2 | (2,65535) | 40 | f | (p)=("(370,370),(186,186)")
3 | (3,65535) | 40 | f | (p)=("(555,555),(371,371)")
4 | (4,65535) | 40 | f | (p)=("(740,740),(556,556)")
5 | (5,65535) | 40 | f | (p)=("(870,870),(741,741)")
6 | (6,65535) | 40 | f | (p)=("(1000,1000),(871,871)")
(6 rows)
</screen>
</para>
</listitem>

16
src/backend/utils/adt/ruleutils.c
View File

@ -1215,6 +1215,22 @@ pg_get_indexdef_columns(Oid indexrelid, bool pretty)
prettyFlags, false);
}
/* Internal version, extensible with flags to control its behavior */
char *
pg_get_indexdef_columns_extended(Oid indexrelid, bits16 flags)
{
bool pretty = ((flags & RULE_INDEXDEF_PRETTY) != 0);
bool keys_only = ((flags & RULE_INDEXDEF_KEYS_ONLY) != 0);
int prettyFlags;
prettyFlags = GET_PRETTY_FLAGS(pretty);
return pg_get_indexdef_worker(indexrelid, 0, NULL,
true, keys_only,
false, false,
prettyFlags, false);
}
/*
* Internal workhorse to decompile an index definition.
*

5
src/include/utils/ruleutils.h
View File

@ -20,9 +20,14 @@
struct Plan; /* avoid including plannodes.h here */
struct PlannedStmt;
/* Flags for pg_get_indexdef_columns_extended() */
#define RULE_INDEXDEF_PRETTY 0x01
#define RULE_INDEXDEF_KEYS_ONLY 0x02 /* ignore included attributes */
extern char *pg_get_indexdef_string(Oid indexrelid);
extern char *pg_get_indexdef_columns(Oid indexrelid, bool pretty);
extern char *pg_get_indexdef_columns_extended(Oid indexrelid,
bits16 flags);
extern char *pg_get_querydef(Query *query, bool pretty);
extern char *pg_get_partkeydef_columns(Oid relid, bool pretty);