*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.239 2007/04/03 16:34:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.240 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/* smgrcommit already done */
AtEOXact_Files();
AtEOXact_ComboCid();
+ AtEOXact_HashTables(true);
pgstat_clear_snapshot();
pgstat_count_xact_commit();
pgstat_report_txn_timestamp(0);
/* smgrcommit already done */
AtEOXact_Files();
AtEOXact_ComboCid();
+ AtEOXact_HashTables(true);
pgstat_clear_snapshot();
CurrentResourceOwner = NULL;
smgrabort();
AtEOXact_Files();
AtEOXact_ComboCid();
+ AtEOXact_HashTables(false);
pgstat_clear_snapshot();
pgstat_count_xact_rollback();
pgstat_report_txn_timestamp(0);
s->parent->subTransactionId);
AtEOSubXact_Files(true, s->subTransactionId,
s->parent->subTransactionId);
+ AtEOSubXact_HashTables(true, s->nestingLevel);
/*
* We need to restore the upper transaction's read-only state, in case the
s->parent->subTransactionId);
AtEOSubXact_Files(false, s->subTransactionId,
s->parent->subTransactionId);
+ AtEOSubXact_HashTables(false, s->nestingLevel);
}
/*
* Copyright (c) 2002-2007, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.73 2007/04/16 18:21:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.74 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "catalog/pg_type.h"
#include "commands/explain.h"
#include "commands/prepare.h"
-#include "funcapi.h"
+#include "miscadmin.h"
#include "parser/analyze.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
Datum
pg_prepared_statement(PG_FUNCTION_ARGS)
{
- FuncCallContext *funcctx;
- HASH_SEQ_STATUS *hash_seq;
- PreparedStatement *prep_stmt;
-
- /* stuff done only on the first call of the function */
- if (SRF_IS_FIRSTCALL())
- {
- TupleDesc tupdesc;
- MemoryContext oldcontext;
-
- /* create a function context for cross-call persistence */
- funcctx = SRF_FIRSTCALL_INIT();
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+ TupleDesc tupdesc;
+ Tuplestorestate *tupstore;
+ MemoryContext per_query_ctx;
+ MemoryContext oldcontext;
+
+ /* check to see if caller supports us returning a tuplestore */
+ if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("set-valued function called in context that cannot accept a set")));
+ if (!(rsinfo->allowedModes & SFRM_Materialize))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("materialize mode required, but it is not " \
+ "allowed in this context")));
- /*
- * switch to memory context appropriate for multiple function calls
- */
- oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+ /* need to build tuplestore in query context */
+ per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
+ oldcontext = MemoryContextSwitchTo(per_query_ctx);
- /* allocate memory for user context */
- if (prepared_queries)
- {
- hash_seq = (HASH_SEQ_STATUS *) palloc(sizeof(HASH_SEQ_STATUS));
- hash_seq_init(hash_seq, prepared_queries);
- funcctx->user_fctx = (void *) hash_seq;
- }
- else
- funcctx->user_fctx = NULL;
+ /*
+ * build tupdesc for result tuples. This must match the definition of
+ * the pg_prepared_statements view in system_views.sql
+ */
+ tupdesc = CreateTemplateTupleDesc(5, false);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "prepare_time",
+ TIMESTAMPTZOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 4, "parameter_types",
+ REGTYPEARRAYOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 5, "from_sql",
+ BOOLOID, -1, 0);
- /*
- * build tupdesc for result tuples. This must match the definition of
- * the pg_prepared_statements view in system_views.sql
- */
- tupdesc = CreateTemplateTupleDesc(5, false);
- TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
- TEXTOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
- TEXTOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 3, "prepare_time",
- TIMESTAMPTZOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 4, "parameter_types",
- REGTYPEARRAYOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 5, "from_sql",
- BOOLOID, -1, 0);
-
- funcctx->tuple_desc = BlessTupleDesc(tupdesc);
- MemoryContextSwitchTo(oldcontext);
- }
+ /*
+ * We put all the tuples into a tuplestore in one scan of the hashtable.
+ * This avoids any issue of the hashtable possibly changing between calls.
+ */
+ tupstore = tuplestore_begin_heap(true, false, work_mem);
- /* stuff done on every call of the function */
- funcctx = SRF_PERCALL_SETUP();
- hash_seq = (HASH_SEQ_STATUS *) funcctx->user_fctx;
+ /* hash table might be uninitialized */
+ if (prepared_queries)
+ {
+ HASH_SEQ_STATUS hash_seq;
+ PreparedStatement *prep_stmt;
- /* if the hash table is uninitialized, we're done */
- if (hash_seq == NULL)
- SRF_RETURN_DONE(funcctx);
+ hash_seq_init(&hash_seq, prepared_queries);
+ while ((prep_stmt = hash_seq_search(&hash_seq)) != NULL)
+ {
+ HeapTuple tuple;
+ Datum values[5];
+ bool nulls[5];
- prep_stmt = hash_seq_search(hash_seq);
- if (prep_stmt)
- {
- Datum result;
- HeapTuple tuple;
- Datum values[5];
- bool nulls[5];
+ /* generate junk in short-term context */
+ MemoryContextSwitchTo(oldcontext);
- MemSet(nulls, 0, sizeof(nulls));
+ MemSet(nulls, 0, sizeof(nulls));
- values[0] = DirectFunctionCall1(textin,
+ values[0] = DirectFunctionCall1(textin,
CStringGetDatum(prep_stmt->stmt_name));
- if (prep_stmt->plansource->query_string == NULL)
- nulls[1] = true;
- else
- values[1] = DirectFunctionCall1(textin,
+ if (prep_stmt->plansource->query_string == NULL)
+ nulls[1] = true;
+ else
+ values[1] = DirectFunctionCall1(textin,
CStringGetDatum(prep_stmt->plansource->query_string));
- values[2] = TimestampTzGetDatum(prep_stmt->prepare_time);
- values[3] = build_regtype_array(prep_stmt->plansource->param_types,
- prep_stmt->plansource->num_params);
- values[4] = BoolGetDatum(prep_stmt->from_sql);
+ values[2] = TimestampTzGetDatum(prep_stmt->prepare_time);
+ values[3] = build_regtype_array(prep_stmt->plansource->param_types,
+ prep_stmt->plansource->num_params);
+ values[4] = BoolGetDatum(prep_stmt->from_sql);
+
+ tuple = heap_form_tuple(tupdesc, values, nulls);
- tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
- result = HeapTupleGetDatum(tuple);
- SRF_RETURN_NEXT(funcctx, result);
+ /* switch to appropriate context while storing the tuple */
+ MemoryContextSwitchTo(per_query_ctx);
+ tuplestore_puttuple(tupstore, tuple);
+ }
}
- SRF_RETURN_DONE(funcctx);
+ /* clean up and return the tuplestore */
+ tuplestore_donestoring(tupstore);
+
+ MemoryContextSwitchTo(oldcontext);
+
+ rsinfo->returnMode = SFRM_Materialize;
+ rsinfo->setResult = tupstore;
+ rsinfo->setDesc = tupdesc;
+
+ return (Datum) 0;
}
/*
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.87 2007/02/27 01:11:25 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.88 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
TupleHashIterator hashiter;
TupleHashEntry entry;
- ResetTupleHashIterator(hashtable, &hashiter);
+ InitTupleHashIterator(hashtable, &hashiter);
while ((entry = ScanTupleHashTable(&hashiter)) != NULL)
{
ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false);
numCols, keyColIdx,
hashtable->cur_eq_funcs,
hashtable->tempcxt))
+ {
+ TermTupleHashIterator(&hashiter);
return true;
+ }
}
+ /* No TermTupleHashIterator call needed here */
return false;
}
* Copyright (c) 2003-2007, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/nodes/tidbitmap.c,v 1.11 2007/01/05 22:19:30 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/nodes/tidbitmap.c,v 1.12 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
tbm_mark_page_lossy(tbm, page->blockno);
if (tbm->nentries <= tbm->maxentries)
- return; /* we have done enough */
+ {
+ /* we have done enough */
+ hash_seq_term(&status);
+ break;
+ }
/*
* Note: tbm_mark_page_lossy may have inserted a lossy chunk into the
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.74 2007/01/05 22:19:43 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.75 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+#include "access/xact.h"
#include "storage/shmem.h"
#include "storage/spin.h"
#include "utils/dynahash.h"
char *tabname; /* table name (for error messages) */
bool isshared; /* true if table is in shared memory */
+ /* freezing a shared table isn't allowed, so we can keep state here */
+ bool frozen; /* true = no more inserts allowed */
+
/* We keep local copies of these fixed values to reduce contention */
Size keysize; /* hash key length in bytes */
long ssize; /* segment size --- must be power of 2 */
static int choose_nelem_alloc(Size entrysize);
static bool init_htab(HTAB *hashp, long nelem);
static void hash_corrupted(HTAB *hashp);
+static void register_seq_scan(HTAB *hashp);
+static void deregister_seq_scan(HTAB *hashp);
+static bool has_seq_scans(HTAB *hashp);
/*
errmsg("out of memory")));
}
+ hashp->frozen = false;
+
hdefault(hashp);
hctl = hashp->hctl;
if (currBucket != NULL)
return (void *) ELEMENTKEY(currBucket);
+ /* disallow inserts if frozen */
+ if (hashp->frozen)
+ elog(ERROR, "cannot insert into a frozen hashtable");
+
currBucket = get_hash_entry(hashp);
if (currBucket == NULL)
{
/* caller is expected to fill the data field on return */
- /* Check if it is time to split a bucket */
- /* Can't split if running in partitioned mode */
+ /*
+ * Check if it is time to split a bucket. Can't split if running
+ * in partitioned mode, nor if table is the subject of any active
+ * hash_seq_search scans. Strange order of these tests is to try
+ * to check cheaper conditions first.
+ */
if (!IS_PARTITIONED(hctl) &&
- hctl->nentries / (long) (hctl->max_bucket + 1) >= hctl->ffactor)
+ hctl->nentries / (long) (hctl->max_bucket + 1) >= hctl->ffactor &&
+ !has_seq_scans(hashp))
{
/*
* NOTE: failure to expand table is not a fatal error, it just
}
/*
- * hash_seq_init/_search
+ * hash_seq_init/_search/_term
* Sequentially search through hash table and return
* all the elements one by one, return NULL when no more.
*
+ * hash_seq_term should be called if and only if the scan is abandoned before
+ * completion; if hash_seq_search returns NULL then it has already done the
+ * end-of-scan cleanup.
+ *
* NOTE: caller may delete the returned element before continuing the scan.
* However, deleting any other element while the scan is in progress is
* UNDEFINED (it might be the one that curIndex is pointing at!). Also,
* if elements are added to the table while the scan is in progress, it is
* unspecified whether they will be visited by the scan or not.
*
+ * NOTE: it is possible to use hash_seq_init/hash_seq_search without any
+ * worry about hash_seq_term cleanup, if the hashtable is first locked against
+ * further insertions by calling hash_freeze. This is used by nodeAgg.c,
+ * wherein it is inconvenient to track whether a scan is still open, and
+ * there's no possibility of further insertions after readout has begun.
+ *
* NOTE: to use this with a partitioned hashtable, caller had better hold
* at least shared lock on all partitions of the table throughout the scan!
+ * We can cope with insertions or deletions by our own backend, but *not*
+ * with concurrent insertions or deletions by another.
*/
void
hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
status->hashp = hashp;
status->curBucket = 0;
status->curEntry = NULL;
+ if (!hashp->frozen)
+ register_seq_scan(hashp);
}
void *
max_bucket = hctl->max_bucket;
if (curBucket > max_bucket)
+ {
+ hash_seq_term(status);
return NULL; /* search is done */
+ }
/*
* first find the right segment in the table directory.
if (++curBucket > max_bucket)
{
status->curBucket = curBucket;
+ hash_seq_term(status);
return NULL; /* search is done */
}
if (++segment_ndx >= ssize)
return (void *) ELEMENTKEY(curElem);
}
+void
+hash_seq_term(HASH_SEQ_STATUS *status)
+{
+ if (!status->hashp->frozen)
+ deregister_seq_scan(status->hashp);
+}
+
+/*
+ * hash_freeze
+ * Freeze a hashtable against future insertions (deletions are
+ * still allowed)
+ *
+ * The reason for doing this is that by preventing any more bucket splits,
+ * we no longer need to worry about registering hash_seq_search scans,
+ * and thus caller need not be careful about ensuring hash_seq_term gets
+ * called at the right times.
+ *
+ * Multiple calls to hash_freeze() are allowed, but you can't freeze a table
+ * with active scans (since hash_seq_term would then do the wrong thing).
+ */
+void
+hash_freeze(HTAB *hashp)
+{
+ if (hashp->isshared)
+ elog(ERROR, "cannot freeze shared hashtable");
+ if (!hashp->frozen && has_seq_scans(hashp))
+ elog(ERROR, "cannot freeze hashtable with active scans");
+ hashp->frozen = true;
+}
+
/********************************* UTILITIES ************************/
;
return i;
}
+
+
+/************************* SEQ SCAN TRACKING ************************/
+
+/*
+ * We track active hash_seq_search scans here. The need for this mechanism
+ * comes from the fact that a scan will get confused if a bucket split occurs
+ * while it's in progress: it might visit entries twice, or even miss some
+ * entirely (if it's partway through the same bucket that splits). Hence
+ * we want to inhibit bucket splits if there are any active scans on the
+ * table being inserted into. This is a fairly rare case in current usage,
+ * so just postponing the split until the next insertion seems sufficient.
+ *
+ * Given present usages of the function, only a few scans are likely to be
+ * open concurrently; so a finite-size stack of open scans seems sufficient,
+ * and we don't worry that linear search is too slow. Note that we do
+ * allow multiple scans of the same hashtable to be open concurrently.
+ *
+ * This mechanism can support concurrent scan and insertion in a shared
+ * hashtable if it's the same backend doing both. It would fail otherwise,
+ * but locking reasons seem to preclude any such scenario anyway, so we don't
+ * worry.
+ *
+ * This arrangement is reasonably robust if a transient hashtable is deleted
+ * without notifying us. The absolute worst case is we might inhibit splits
+ * in another table created later at exactly the same address. We will give
+ * a warning at transaction end for reference leaks, so any bugs leading to
+ * lack of notification should be easy to catch.
+ */
+
+#define MAX_SEQ_SCANS 100
+
+static HTAB *seq_scan_tables[MAX_SEQ_SCANS]; /* tables being scanned */
+static int seq_scan_level[MAX_SEQ_SCANS]; /* subtransaction nest level */
+static int num_seq_scans = 0;
+
+
+/* Register a table as having an active hash_seq_search scan */
+static void
+register_seq_scan(HTAB *hashp)
+{
+ if (num_seq_scans >= MAX_SEQ_SCANS)
+ elog(ERROR, "too many active hash_seq_search scans");
+ seq_scan_tables[num_seq_scans] = hashp;
+ seq_scan_level[num_seq_scans] = GetCurrentTransactionNestLevel();
+ num_seq_scans++;
+}
+
+/* Deregister an active scan */
+static void
+deregister_seq_scan(HTAB *hashp)
+{
+ int i;
+
+ /* Search backward since it's most likely at the stack top */
+ for (i = num_seq_scans - 1; i >= 0; i--)
+ {
+ if (seq_scan_tables[i] == hashp)
+ {
+ seq_scan_tables[i] = seq_scan_tables[num_seq_scans - 1];
+ seq_scan_level[i] = seq_scan_level[num_seq_scans - 1];
+ num_seq_scans--;
+ return;
+ }
+ }
+ elog(ERROR, "no hash_seq_search scan for hash table \"%s\"",
+ hashp->tabname);
+}
+
+/* Check if a table has any active scan */
+static bool
+has_seq_scans(HTAB *hashp)
+{
+ int i;
+
+ for (i = 0; i < num_seq_scans; i++)
+ {
+ if (seq_scan_tables[i] == hashp)
+ return true;
+ }
+ return false;
+}
+
+/* Clean up any open scans at end of transaction */
+void
+AtEOXact_HashTables(bool isCommit)
+{
+ /*
+ * During abort cleanup, open scans are expected; just silently clean 'em
+ * out. An open scan at commit means someone forgot a hash_seq_term()
+ * call, so complain.
+ *
+ * Note: it's tempting to try to print the tabname here, but refrain for
+ * fear of touching deallocated memory. This isn't a user-facing message
+ * anyway, so it needn't be pretty.
+ */
+ if (isCommit)
+ {
+ int i;
+
+ for (i = 0; i < num_seq_scans; i++)
+ {
+ elog(WARNING, "leaked hash_seq_search scan for hash table %p",
+ seq_scan_tables[i]);
+ }
+ }
+ num_seq_scans = 0;
+}
+
+/* Clean up any open scans at end of subtransaction */
+void
+AtEOSubXact_HashTables(bool isCommit, int nestDepth)
+{
+ int i;
+
+ /*
+ * Search backward to make cleanup easy. Note we must check all entries,
+ * not only those at the end of the array, because deletion technique
+ * doesn't keep them in order.
+ */
+ for (i = num_seq_scans - 1; i >= 0; i--)
+ {
+ if (seq_scan_level[i] >= nestDepth)
+ {
+ if (isCommit)
+ elog(WARNING, "leaked hash_seq_search scan for hash table %p",
+ seq_scan_tables[i]);
+ seq_scan_tables[i] = seq_scan_tables[num_seq_scans - 1];
+ seq_scan_level[i] = seq_scan_level[num_seq_scans - 1];
+ num_seq_scans--;
+ }
+ }
+}
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.102 2007/04/26 16:13:13 neilc Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.103 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "commands/portalcmds.h"
-#include "funcapi.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
/* Zap all non-holdable portals */
PortalDrop(portal, true);
- /* Restart the iteration */
+ /* Restart the iteration in case that led to other drops */
+ /* XXX is this really necessary? */
+ hash_seq_term(&status);
hash_seq_init(&status, PortalHashTable);
}
}
Datum
pg_cursor(PG_FUNCTION_ARGS)
{
- FuncCallContext *funcctx;
- HASH_SEQ_STATUS *hash_seq;
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+ TupleDesc tupdesc;
+ Tuplestorestate *tupstore;
+ MemoryContext per_query_ctx;
+ MemoryContext oldcontext;
+ HASH_SEQ_STATUS hash_seq;
PortalHashEnt *hentry;
- /* stuff done only on the first call of the function */
- if (SRF_IS_FIRSTCALL())
- {
- MemoryContext oldcontext;
- TupleDesc tupdesc;
-
- /* create a function context for cross-call persistence */
- funcctx = SRF_FIRSTCALL_INIT();
-
- /*
- * switch to memory context appropriate for multiple function calls
- */
- oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
-
- if (PortalHashTable)
- {
- hash_seq = (HASH_SEQ_STATUS *) palloc(sizeof(HASH_SEQ_STATUS));
- hash_seq_init(hash_seq, PortalHashTable);
- funcctx->user_fctx = (void *) hash_seq;
- }
- else
- funcctx->user_fctx = NULL;
-
- /*
- * build tupdesc for result tuples. This must match the definition of
- * the pg_cursors view in system_views.sql
- */
- tupdesc = CreateTemplateTupleDesc(6, false);
- TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
- TEXTOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
- TEXTOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 3, "is_holdable",
- BOOLOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 4, "is_binary",
- BOOLOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 5, "is_scrollable",
- BOOLOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 6, "creation_time",
- TIMESTAMPTZOID, -1, 0);
-
- funcctx->tuple_desc = BlessTupleDesc(tupdesc);
- MemoryContextSwitchTo(oldcontext);
- }
-
- /* stuff done on every call of the function */
- funcctx = SRF_PERCALL_SETUP();
- hash_seq = (HASH_SEQ_STATUS *) funcctx->user_fctx;
+ /* check to see if caller supports us returning a tuplestore */
+ if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("set-valued function called in context that cannot accept a set")));
+ if (!(rsinfo->allowedModes & SFRM_Materialize))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("materialize mode required, but it is not " \
+ "allowed in this context")));
+
+ /* need to build tuplestore in query context */
+ per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
+ oldcontext = MemoryContextSwitchTo(per_query_ctx);
- /* if the hash table is uninitialized, we're done */
- if (hash_seq == NULL)
- SRF_RETURN_DONE(funcctx);
+ /*
+ * build tupdesc for result tuples. This must match the definition of
+ * the pg_cursors view in system_views.sql
+ */
+ tupdesc = CreateTemplateTupleDesc(6, false);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 3, "is_holdable",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 4, "is_binary",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 5, "is_scrollable",
+ BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 6, "creation_time",
+ TIMESTAMPTZOID, -1, 0);
- /* loop until we find a visible portal or hit the end of the list */
- while ((hentry = hash_seq_search(hash_seq)) != NULL)
- {
- if (hentry->portal->visible)
- break;
- }
+ /*
+ * We put all the tuples into a tuplestore in one scan of the hashtable.
+ * This avoids any issue of the hashtable possibly changing between calls.
+ */
+ tupstore = tuplestore_begin_heap(true, false, work_mem);
- if (hentry)
+ hash_seq_init(&hash_seq, PortalHashTable);
+ while ((hentry = hash_seq_search(&hash_seq)) != NULL)
{
- Portal portal;
- Datum result;
+ Portal portal = hentry->portal;
HeapTuple tuple;
Datum values[6];
bool nulls[6];
- portal = hentry->portal;
+ /* report only "visible" entries */
+ if (!portal->visible)
+ continue;
+
+ /* generate junk in short-term context */
+ MemoryContextSwitchTo(oldcontext);
+
MemSet(nulls, 0, sizeof(nulls));
values[0] = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
values[4] = BoolGetDatum(portal->cursorOptions & CURSOR_OPT_SCROLL);
values[5] = TimestampTzGetDatum(portal->creation_time);
- tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
- result = HeapTupleGetDatum(tuple);
- SRF_RETURN_NEXT(funcctx, result);
+ tuple = heap_form_tuple(tupdesc, values, nulls);
+
+ /* switch to appropriate context while storing the tuple */
+ MemoryContextSwitchTo(per_query_ctx);
+ tuplestore_puttuple(tupstore, tuple);
}
- SRF_RETURN_DONE(funcctx);
+ /* clean up and return the tuplestore */
+ tuplestore_donestoring(tupstore);
+
+ MemoryContextSwitchTo(oldcontext);
+
+ rsinfo->returnMode = SFRM_Materialize;
+ rsinfo->setResult = tupstore;
+ rsinfo->setDesc = tupdesc;
+
+ return (Datum) 0;
}
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.171 2007/03/27 23:21:12 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.172 2007/04/26 23:24:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
typedef HASH_SEQ_STATUS TupleHashIterator;
-#define ResetTupleHashIterator(htable, iter) \
+/*
+ * Use InitTupleHashIterator/TermTupleHashIterator for a read/write scan.
+ * Use ResetTupleHashIterator if the table can be frozen (in this case no
+ * explicit scan termination is needed).
+ */
+#define InitTupleHashIterator(htable, iter) \
hash_seq_init(iter, (htable)->hashtab)
+#define TermTupleHashIterator(iter) \
+ hash_seq_term(iter)
+#define ResetTupleHashIterator(htable, iter) \
+ do { \
+ hash_freeze((htable)->hashtab); \
+ hash_seq_init(iter, (htable)->hashtab); \
+ } while (0)
#define ScanTupleHashTable(iter) \
((TupleHashEntry) hash_seq_search(iter))
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.46 2007/01/05 22:19:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.47 2007/04/26 23:24:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern long hash_get_num_entries(HTAB *hashp);
extern void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp);
extern void *hash_seq_search(HASH_SEQ_STATUS *status);
+extern void hash_seq_term(HASH_SEQ_STATUS *status);
+extern void hash_freeze(HTAB *hashp);
extern Size hash_estimate_size(long num_entries, Size entrysize);
extern long hash_select_dirsize(long num_entries);
extern Size hash_get_shared_size(HASHCTL *info, int flags);
+extern void AtEOXact_HashTables(bool isCommit);
+extern void AtEOSubXact_HashTables(bool isCommit, int nestDepth);
/*
* prototypes for functions in hashfn.c
projects / postgresql.git / commitdiff