/* * contrib/pgrowlocks/pgrowlocks.c * * Copyright (c) 2005-2006 Tatsuo Ishii * * Permission to use, copy, modify, and distribute this software and * its documentation for any purpose, without fee, and without a * written agreement is hereby granted, provided that the above * copyright notice and this paragraph and the following two * paragraphs appear in all copies. * * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT, * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. */ #include "postgres.h" #include "access/multixact.h" #include "access/relscan.h" #include "access/xact.h" #include "catalog/namespace.h" #include "funcapi.h" #include "miscadmin.h" #include "storage/bufmgr.h" #include "storage/procarray.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/rel.h" #include "utils/snapmgr.h" #include "utils/tqual.h" PG_MODULE_MAGIC; PG_FUNCTION_INFO_V1(pgrowlocks); /* ---------- * pgrowlocks: * returns tids of rows being locked * ---------- */ #define NCHARS 32 typedef struct { Relation rel; HeapScanDesc scan; int ncolumns; } MyData; #define Atnum_tid 0 #define Atnum_xmax 1 #define Atnum_ismulti 2 #define Atnum_xids 3 #define Atnum_modes 4 #define Atnum_pids 5 Datum pgrowlocks(PG_FUNCTION_ARGS) { FuncCallContext *funcctx; HeapScanDesc scan; HeapTuple tuple; TupleDesc tupdesc; AttInMetadata *attinmeta; Datum result; MyData *mydata; Relation rel; if (SRF_IS_FIRSTCALL()) { text *relname; RangeVar *relrv; MemoryContext oldcontext; AclResult aclresult; funcctx = SRF_FIRSTCALL_INIT(); oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); /* Build a tuple descriptor for our result type */ if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) elog(ERROR, "return type must be a row type"); attinmeta = TupleDescGetAttInMetadata(tupdesc); funcctx->attinmeta = attinmeta; relname = PG_GETARG_TEXT_P(0); relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname)); rel = heap_openrv(relrv, AccessShareLock); /* check permissions: must have SELECT on table */ aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(), ACL_SELECT); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_CLASS, RelationGetRelationName(rel)); scan = heap_beginscan(rel, GetActiveSnapshot(), 0, NULL); mydata = palloc(sizeof(*mydata)); mydata->rel = rel; mydata->scan = scan; mydata->ncolumns = tupdesc->natts; funcctx->user_fctx = mydata; MemoryContextSwitchTo(oldcontext); } funcctx = SRF_PERCALL_SETUP(); attinmeta = funcctx->attinmeta; mydata = (MyData *) funcctx->user_fctx; scan = mydata->scan; /* scan the relation */ while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) { HTSU_Result htsu; TransactionId xmax; uint16 infomask; /* must hold a buffer lock to call HeapTupleSatisfiesUpdate */ LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE); htsu = HeapTupleSatisfiesUpdate(tuple, GetCurrentCommandId(false), scan->rs_cbuf); xmax = HeapTupleHeaderGetRawXmax(tuple->t_data); infomask = tuple->t_data->t_infomask; /* * A tuple is locked if HTSU returns BeingUpdated. */ if (htsu == HeapTupleBeingUpdated) { char **values; values = (char **) palloc(mydata->ncolumns * sizeof(char *)); values[Atnum_tid] = (char *) DirectFunctionCall1(tidout, PointerGetDatum(&tuple->t_self)); values[Atnum_xmax] = palloc(NCHARS * sizeof(char)); snprintf(values[Atnum_xmax], NCHARS, "%d", xmax); if (infomask & HEAP_XMAX_IS_MULTI) { MultiXactMember *members; int nmembers; bool first = true; bool allow_old; values[Atnum_ismulti] = pstrdup("true"); allow_old = !(infomask & HEAP_LOCK_MASK) && (infomask & HEAP_XMAX_LOCK_ONLY); nmembers = GetMultiXactIdMembers(xmax, &members, allow_old, false); if (nmembers == -1) { values[Atnum_xids] = "{0}"; values[Atnum_modes] = "{transient upgrade status}"; values[Atnum_pids] = "{0}"; } else { int j; values[Atnum_xids] = palloc(NCHARS * nmembers); values[Atnum_modes] = palloc(NCHARS * nmembers); values[Atnum_pids] = palloc(NCHARS * nmembers); strcpy(values[Atnum_xids], "{"); strcpy(values[Atnum_modes], "{"); strcpy(values[Atnum_pids], "{"); for (j = 0; j < nmembers; j++) { char buf[NCHARS]; if (!first) { strcat(values[Atnum_xids], ","); strcat(values[Atnum_modes], ","); strcat(values[Atnum_pids], ","); } snprintf(buf, NCHARS, "%d", members[j].xid); strcat(values[Atnum_xids], buf); switch (members[j].status) { case MultiXactStatusUpdate: snprintf(buf, NCHARS, "Update"); break; case MultiXactStatusNoKeyUpdate: snprintf(buf, NCHARS, "No Key Update"); break; case MultiXactStatusForUpdate: snprintf(buf, NCHARS, "For Update"); break; case MultiXactStatusForNoKeyUpdate: snprintf(buf, NCHARS, "For No Key Update"); break; case MultiXactStatusForShare: snprintf(buf, NCHARS, "Share"); break; case MultiXactStatusForKeyShare: snprintf(buf, NCHARS, "Key Share"); break; } strcat(values[Atnum_modes], buf); snprintf(buf, NCHARS, "%d", BackendXidGetPid(members[j].xid)); strcat(values[Atnum_pids], buf); first = false; } strcat(values[Atnum_xids], "}"); strcat(values[Atnum_modes], "}"); strcat(values[Atnum_pids], "}"); } } else { values[Atnum_ismulti] = pstrdup("false"); values[Atnum_xids] = palloc(NCHARS * sizeof(char)); snprintf(values[Atnum_xids], NCHARS, "{%d}", xmax); values[Atnum_modes] = palloc(NCHARS); if (infomask & HEAP_XMAX_LOCK_ONLY) { if (HEAP_XMAX_IS_SHR_LOCKED(infomask)) snprintf(values[Atnum_modes], NCHARS, "{For Share}"); else if (HEAP_XMAX_IS_KEYSHR_LOCKED(infomask)) snprintf(values[Atnum_modes], NCHARS, "{For Key Share}"); else if (HEAP_XMAX_IS_EXCL_LOCKED(infomask)) { if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED) snprintf(values[Atnum_modes], NCHARS, "{For Update}"); else snprintf(values[Atnum_modes], NCHARS, "{For No Key Update}"); } else /* neither keyshare nor exclusive bit it set */ snprintf(values[Atnum_modes], NCHARS, "{transient upgrade status}"); } else { if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED) snprintf(values[Atnum_modes], NCHARS, "{Update}"); else snprintf(values[Atnum_modes], NCHARS, "{No Key Update}"); } values[Atnum_pids] = palloc(NCHARS * sizeof(char)); snprintf(values[Atnum_pids], NCHARS, "{%d}", BackendXidGetPid(xmax)); } LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK); /* build a tuple */ tuple = BuildTupleFromCStrings(attinmeta, values); /* make the tuple into a datum */ result = HeapTupleGetDatum(tuple); /* * no need to pfree what we allocated; it's on a short-lived * memory context anyway */ SRF_RETURN_NEXT(funcctx, result); } else { LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK); } } heap_endscan(scan); heap_close(mydata->rel, AccessShareLock); SRF_RETURN_DONE(funcctx); }