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pgrowlocks.c File Reference
#include "postgres.h"
#include "access/heapam.h"
#include "access/multixact.h"
#include "access/relscan.h"
#include "access/tableam.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "catalog/pg_am_d.h"
#include "catalog/pg_authid.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/fmgrprotos.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/varlena.h"
Include dependency graph for pgrowlocks.c:

Go to the source code of this file.

Macros

#define NCHARS   32
 
#define Atnum_tid   0
 
#define Atnum_xmax   1
 
#define Atnum_ismulti   2
 
#define Atnum_xids   3
 
#define Atnum_modes   4
 
#define Atnum_pids   5
 

Functions

 PG_FUNCTION_INFO_V1 (pgrowlocks)
 
Datum pgrowlocks (PG_FUNCTION_ARGS)
 

Variables

 PG_MODULE_MAGIC
 

Macro Definition Documentation

◆ Atnum_ismulti

#define Atnum_ismulti   2

Definition at line 59 of file pgrowlocks.c.

◆ Atnum_modes

#define Atnum_modes   4

Definition at line 61 of file pgrowlocks.c.

◆ Atnum_pids

#define Atnum_pids   5

Definition at line 62 of file pgrowlocks.c.

◆ Atnum_tid

#define Atnum_tid   0

Definition at line 57 of file pgrowlocks.c.

◆ Atnum_xids

#define Atnum_xids   3

Definition at line 60 of file pgrowlocks.c.

◆ Atnum_xmax

#define Atnum_xmax   1

Definition at line 58 of file pgrowlocks.c.

◆ NCHARS

#define NCHARS   32

Definition at line 55 of file pgrowlocks.c.

Function Documentation

◆ PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1 ( pgrowlocks  )

◆ pgrowlocks()

Datum pgrowlocks ( PG_FUNCTION_ARGS  )

Definition at line 65 of file pgrowlocks.c.

66{
68 ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
69 AttInMetadata *attinmeta;
70 Relation rel;
71 RangeVar *relrv;
72 TableScanDesc scan;
73 HeapScanDesc hscan;
74 HeapTuple tuple;
75 AclResult aclresult;
76 char **values;
77
78 InitMaterializedSRF(fcinfo, 0);
79
80 /* Access the table */
82 rel = relation_openrv(relrv, AccessShareLock);
83
84 if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
86 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
87 errmsg("\"%s\" is a partitioned table",
89 errdetail("Partitioned tables do not contain rows.")));
90 else if (rel->rd_rel->relkind != RELKIND_RELATION)
92 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
93 errmsg("\"%s\" is not a table",
95 else if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
97 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
98 errmsg("only heap AM is supported")));
99
100 /*
101 * check permissions: must have SELECT on table or be in
102 * pg_stat_scan_tables
103 */
104 aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
105 ACL_SELECT);
106 if (aclresult != ACLCHECK_OK)
107 aclresult = has_privs_of_role(GetUserId(), ROLE_PG_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
108
109 if (aclresult != ACLCHECK_OK)
110 aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
112
113 /* Scan the relation */
114 scan = table_beginscan(rel, GetActiveSnapshot(), 0, NULL);
115 hscan = (HeapScanDesc) scan;
116
117 attinmeta = TupleDescGetAttInMetadata(rsinfo->setDesc);
118
119 values = (char **) palloc(rsinfo->setDesc->natts * sizeof(char *));
120
121 while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
122 {
123 TM_Result htsu;
124 TransactionId xmax;
125 uint16 infomask;
126
127 /* must hold a buffer lock to call HeapTupleSatisfiesUpdate */
128 LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_SHARE);
129
130 htsu = HeapTupleSatisfiesUpdate(tuple,
131 GetCurrentCommandId(false),
132 hscan->rs_cbuf);
133 xmax = HeapTupleHeaderGetRawXmax(tuple->t_data);
134 infomask = tuple->t_data->t_infomask;
135
136 /*
137 * A tuple is locked if HTSU returns BeingModified.
138 */
139 if (htsu == TM_BeingModified)
140 {
142 PointerGetDatum(&tuple->t_self));
143
144 values[Atnum_xmax] = palloc(NCHARS * sizeof(char));
145 snprintf(values[Atnum_xmax], NCHARS, "%u", xmax);
146 if (infomask & HEAP_XMAX_IS_MULTI)
147 {
148 MultiXactMember *members;
149 int nmembers;
150 bool first = true;
151 bool allow_old;
152
153 values[Atnum_ismulti] = pstrdup("true");
154
155 allow_old = HEAP_LOCKED_UPGRADED(infomask);
156 nmembers = GetMultiXactIdMembers(xmax, &members, allow_old,
157 false);
158 if (nmembers == -1)
159 {
160 values[Atnum_xids] = "{0}";
161 values[Atnum_modes] = "{transient upgrade status}";
162 values[Atnum_pids] = "{0}";
163 }
164 else
165 {
166 int j;
167
168 values[Atnum_xids] = palloc(NCHARS * nmembers);
169 values[Atnum_modes] = palloc(NCHARS * nmembers);
170 values[Atnum_pids] = palloc(NCHARS * nmembers);
171
172 strcpy(values[Atnum_xids], "{");
173 strcpy(values[Atnum_modes], "{");
174 strcpy(values[Atnum_pids], "{");
175
176 for (j = 0; j < nmembers; j++)
177 {
178 char buf[NCHARS];
179
180 if (!first)
181 {
182 strcat(values[Atnum_xids], ",");
183 strcat(values[Atnum_modes], ",");
184 strcat(values[Atnum_pids], ",");
185 }
186 snprintf(buf, NCHARS, "%u", members[j].xid);
187 strcat(values[Atnum_xids], buf);
188 switch (members[j].status)
189 {
191 snprintf(buf, NCHARS, "Update");
192 break;
194 snprintf(buf, NCHARS, "No Key Update");
195 break;
197 snprintf(buf, NCHARS, "For Update");
198 break;
200 snprintf(buf, NCHARS, "For No Key Update");
201 break;
203 snprintf(buf, NCHARS, "For Share");
204 break;
206 snprintf(buf, NCHARS, "For Key Share");
207 break;
208 }
209 strcat(values[Atnum_modes], buf);
210 snprintf(buf, NCHARS, "%d",
211 BackendXidGetPid(members[j].xid));
212 strcat(values[Atnum_pids], buf);
213
214 first = false;
215 }
216
217 strcat(values[Atnum_xids], "}");
218 strcat(values[Atnum_modes], "}");
219 strcat(values[Atnum_pids], "}");
220 }
221 }
222 else
223 {
224 values[Atnum_ismulti] = pstrdup("false");
225
226 values[Atnum_xids] = palloc(NCHARS * sizeof(char));
227 snprintf(values[Atnum_xids], NCHARS, "{%u}", xmax);
228
230 if (infomask & HEAP_XMAX_LOCK_ONLY)
231 {
232 if (HEAP_XMAX_IS_SHR_LOCKED(infomask))
233 snprintf(values[Atnum_modes], NCHARS, "{For Share}");
234 else if (HEAP_XMAX_IS_KEYSHR_LOCKED(infomask))
235 snprintf(values[Atnum_modes], NCHARS, "{For Key Share}");
236 else if (HEAP_XMAX_IS_EXCL_LOCKED(infomask))
237 {
238 if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)
239 snprintf(values[Atnum_modes], NCHARS, "{For Update}");
240 else
241 snprintf(values[Atnum_modes], NCHARS, "{For No Key Update}");
242 }
243 else
244 /* neither keyshare nor exclusive bit it set */
246 "{transient upgrade status}");
247 }
248 else
249 {
250 if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)
251 snprintf(values[Atnum_modes], NCHARS, "{Update}");
252 else
253 snprintf(values[Atnum_modes], NCHARS, "{No Key Update}");
254 }
255
256 values[Atnum_pids] = palloc(NCHARS * sizeof(char));
258 BackendXidGetPid(xmax));
259 }
260
261 LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_UNLOCK);
262
263 /* build a tuple */
264 tuple = BuildTupleFromCStrings(attinmeta, values);
265 tuplestore_puttuple(rsinfo->setResult, tuple);
266 }
267 else
268 {
269 LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_UNLOCK);
270 }
271 }
272
273 table_endscan(scan);
275 return (Datum) 0;
276}
bool has_privs_of_role(Oid member, Oid role)
Definition: acl.c:5268
AclResult
Definition: acl.h:182
@ ACLCHECK_NO_PRIV
Definition: acl.h:184
@ ACLCHECK_OK
Definition: acl.h:183
void aclcheck_error(AclResult aclerr, ObjectType objtype, const char *objectname)
Definition: aclchk.c:2622
AclResult pg_class_aclcheck(Oid table_oid, Oid roleid, AclMode mode)
Definition: aclchk.c:4013
static Datum values[MAXATTR]
Definition: bootstrap.c:151
void LockBuffer(Buffer buffer, int mode)
Definition: bufmgr.c:5158
#define BUFFER_LOCK_UNLOCK
Definition: bufmgr.h:189
#define BUFFER_LOCK_SHARE
Definition: bufmgr.h:190
uint16_t uint16
Definition: c.h:484
uint32 TransactionId
Definition: c.h:606
int errdetail(const char *fmt,...)
Definition: elog.c:1203
int errcode(int sqlerrcode)
Definition: elog.c:853
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values)
Definition: execTuples.c:2322
AttInMetadata * TupleDescGetAttInMetadata(TupleDesc tupdesc)
Definition: execTuples.c:2273
#define PG_GETARG_TEXT_PP(n)
Definition: fmgr.h:309
#define DirectFunctionCall1(func, arg1)
Definition: fmgr.h:641
void InitMaterializedSRF(FunctionCallInfo fcinfo, bits32 flags)
Definition: funcapi.c:76
HeapTuple heap_getnext(TableScanDesc sscan, ScanDirection direction)
Definition: heapam.c:1246
struct HeapScanDescData * HeapScanDesc
Definition: heapam.h:110
TM_Result HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid, Buffer buffer)
#define HEAP_XMAX_IS_EXCL_LOCKED(infomask)
Definition: htup_details.h:261
#define HEAP_XMAX_IS_KEYSHR_LOCKED(infomask)
Definition: htup_details.h:263
#define HEAP_KEYS_UPDATED
Definition: htup_details.h:275
#define HEAP_XMAX_LOCK_ONLY
Definition: htup_details.h:197
#define HEAP_XMAX_IS_MULTI
Definition: htup_details.h:209
#define HeapTupleHeaderGetRawXmax(tup)
Definition: htup_details.h:371
#define HEAP_XMAX_IS_SHR_LOCKED(infomask)
Definition: htup_details.h:259
#define HEAP_LOCKED_UPGRADED(infomask)
Definition: htup_details.h:249
int j
Definition: isn.c:73
#define AccessShareLock
Definition: lockdefs.h:36
char * pstrdup(const char *in)
Definition: mcxt.c:1696
void * palloc(Size size)
Definition: mcxt.c:1317
Oid GetUserId(void)
Definition: miscinit.c:517
int GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members, bool from_pgupgrade, bool isLockOnly)
Definition: multixact.c:1299
@ MultiXactStatusForShare
Definition: multixact.h:40
@ MultiXactStatusForNoKeyUpdate
Definition: multixact.h:41
@ MultiXactStatusNoKeyUpdate
Definition: multixact.h:44
@ MultiXactStatusUpdate
Definition: multixact.h:46
@ MultiXactStatusForUpdate
Definition: multixact.h:42
@ MultiXactStatusForKeyShare
Definition: multixact.h:39
RangeVar * makeRangeVarFromNameList(const List *names)
Definition: namespace.c:3554
ObjectType get_relkind_objtype(char relkind)
#define ACL_SELECT
Definition: parsenodes.h:77
NameData relname
Definition: pg_class.h:38
static char * buf
Definition: pg_test_fsync.c:72
#define Atnum_modes
Definition: pgrowlocks.c:61
#define NCHARS
Definition: pgrowlocks.c:55
#define Atnum_xids
Definition: pgrowlocks.c:60
#define Atnum_ismulti
Definition: pgrowlocks.c:59
#define Atnum_tid
Definition: pgrowlocks.c:57
#define Atnum_pids
Definition: pgrowlocks.c:62
#define Atnum_xmax
Definition: pgrowlocks.c:58
#define snprintf
Definition: port.h:238
static Datum PointerGetDatum(const void *X)
Definition: postgres.h:322
uintptr_t Datum
Definition: postgres.h:64
int BackendXidGetPid(TransactionId xid)
Definition: procarray.c:3256
#define RelationGetRelid(relation)
Definition: rel.h:505
#define RelationGetRelationName(relation)
Definition: rel.h:539
@ ForwardScanDirection
Definition: sdir.h:28
Snapshot GetActiveSnapshot(void)
Definition: snapmgr.c:728
Relation relation_openrv(const RangeVar *relation, LOCKMODE lockmode)
Definition: relation.c:137
TupleDesc setDesc
Definition: execnodes.h:343
Tuplestorestate * setResult
Definition: execnodes.h:342
Definition: c.h:641
void table_close(Relation relation, LOCKMODE lockmode)
Definition: table.c:126
static TableScanDesc table_beginscan(Relation rel, Snapshot snapshot, int nkeys, struct ScanKeyData *key)
Definition: tableam.h:912
static void table_endscan(TableScanDesc scan)
Definition: tableam.h:1024
TM_Result
Definition: tableam.h:79
@ TM_BeingModified
Definition: tableam.h:106
Datum tidout(PG_FUNCTION_ARGS)
Definition: tid.c:119
void tuplestore_puttuple(Tuplestorestate *state, HeapTuple tuple)
Definition: tuplestore.c:764
List * textToQualifiedNameList(text *textval)
Definition: varlena.c:3374
CommandId GetCurrentCommandId(bool used)
Definition: xact.c:828

References AccessShareLock, ACL_SELECT, aclcheck_error(), ACLCHECK_NO_PRIV, ACLCHECK_OK, Atnum_ismulti, Atnum_modes, Atnum_pids, Atnum_tid, Atnum_xids, Atnum_xmax, BackendXidGetPid(), buf, BUFFER_LOCK_SHARE, BUFFER_LOCK_UNLOCK, BuildTupleFromCStrings(), DirectFunctionCall1, ereport, errcode(), errdetail(), errmsg(), ERROR, ForwardScanDirection, get_relkind_objtype(), GetActiveSnapshot(), GetCurrentCommandId(), GetMultiXactIdMembers(), GetUserId(), has_privs_of_role(), heap_getnext(), HEAP_KEYS_UPDATED, HEAP_LOCKED_UPGRADED, HEAP_XMAX_IS_EXCL_LOCKED, HEAP_XMAX_IS_KEYSHR_LOCKED, HEAP_XMAX_IS_MULTI, HEAP_XMAX_IS_SHR_LOCKED, HEAP_XMAX_LOCK_ONLY, HeapTupleHeaderGetRawXmax, HeapTupleSatisfiesUpdate(), InitMaterializedSRF(), j, LockBuffer(), makeRangeVarFromNameList(), MultiXactStatusForKeyShare, MultiXactStatusForNoKeyUpdate, MultiXactStatusForShare, MultiXactStatusForUpdate, MultiXactStatusNoKeyUpdate, MultiXactStatusUpdate, TupleDescData::natts, NCHARS, palloc(), pg_class_aclcheck(), PG_GETARG_TEXT_PP, PointerGetDatum(), pstrdup(), relation_openrv(), RelationGetRelationName, RelationGetRelid, relname, ReturnSetInfo::setDesc, ReturnSetInfo::setResult, snprintf, table_beginscan(), table_close(), table_endscan(), textToQualifiedNameList(), tidout(), TM_BeingModified, TupleDescGetAttInMetadata(), tuplestore_puttuple(), and values.

Variable Documentation

◆ PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 45 of file pgrowlocks.c.