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matview.c
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matview.c
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/*-------------------------------------------------------------------------
*
* matview.c
* Incremental view maintenance extension
* Routines for incremental maintenance of IMMVs
*
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
* Portions Copyright (c) 2022, IVM Development Group
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/multixact.h"
#include "access/table.h"
#include "access/tableam.h"
#include "access/xact.h"
#include "catalog/pg_depend.h"
#include "catalog/heap.h"
#include "catalog/pg_trigger.h"
#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/matview.h"
#include "commands/tablecmds.h"
#include "executor/execdesc.h"
#include "executor/executor.h"
#include "executor/spi.h"
#include "executor/tstoreReceiver.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/analyze.h"
#include "parser/parse_clause.h"
#include "parser/parse_func.h"
#include "parser/parse_relation.h"
#include "parser/parser.h"
#include "pgstat.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rowsecurity.h"
#include "storage/lmgr.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/fmgrprotos.h"
#include "utils/hsearch.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/typcache.h"
#include "pg_ivm.h"
#define MV_INIT_QUERYHASHSIZE 16
/* MV query type codes */
#define MV_PLAN_RECALC 1
#define MV_PLAN_SET_VALUE 2
/*
* MI_QueryKey
*
* The key identifying a prepared SPI plan in our query hashtable
*/
typedef struct MV_QueryKey
{
Oid matview_id; /* OID of materialized view */
int32 query_type; /* query type ID, see MV_PLAN_XXX above */
} MV_QueryKey;
/*
* MV_QueryHashEntry
*
* Hash entry for cached plans used to maintain materialized views.
*/
typedef struct MV_QueryHashEntry
{
MV_QueryKey key;
SPIPlanPtr plan;
#if PG_VERSION_NUM < 170000
OverrideSearchPath *search_path; /* search_path used for parsing
* and planning */
#else
SearchPathMatcher *search_path; /* search_path used for parsing
* and planning */
#endif
} MV_QueryHashEntry;
/*
* MV_TriggerHashEntry
*
* Hash entry for base tables on which IVM trigger is invoked
*/
typedef struct MV_TriggerHashEntry
{
Oid matview_id; /* OID of the materialized view */
int before_trig_count; /* count of before triggers invoked */
int after_trig_count; /* count of after triggers invoked */
Snapshot snapshot; /* Snapshot just before table change */
List *tables; /* List of MV_TriggerTable */
bool has_old; /* tuples are deleted from any table? */
bool has_new; /* tuples are inserted into any table? */
} MV_TriggerHashEntry;
/*
* MV_TriggerTable
*
* IVM related data for tables on which the trigger is invoked.
*/
typedef struct MV_TriggerTable
{
Oid table_id; /* OID of the modified table */
List *old_tuplestores; /* tuplestores for deleted tuples */
List *new_tuplestores; /* tuplestores for inserted tuples */
List *old_rtes; /* RTEs of ENRs for old_tuplestores*/
List *new_rtes; /* RTEs of ENRs for new_tuplestores */
List *rte_paths; /* List of paths to RTE index of the modified table */
RangeTblEntry *original_rte; /* the original RTE saved before rewriting query */
Relation rel; /* relation of the modified table */
TupleTableSlot *slot; /* for checking visibility in the pre-state table */
} MV_TriggerTable;
static HTAB *mv_query_cache = NULL;
static HTAB *mv_trigger_info = NULL;
static bool in_delta_calculation = false;
/* kind of IVM operation for the view */
typedef enum
{
IVM_ADD,
IVM_SUB
} IvmOp;
/* ENR name for materialized view delta */
#define NEW_DELTA_ENRNAME "new_delta"
#define OLD_DELTA_ENRNAME "old_delta"
static int immv_maintenance_depth = 0;
static uint64 refresh_immv_datafill(DestReceiver *dest, Query *query,
QueryEnvironment *queryEnv,
TupleDesc *resultTupleDesc,
const char *queryString);
static void refresh_by_heap_swap(Oid matviewOid, Oid OIDNewHeap, char relpersistence);
static void OpenImmvIncrementalMaintenance(void);
static void CloseImmvIncrementalMaintenance(void);
static Query *rewrite_query_for_preupdate_state(Query *query, List *tables,
ParseState *pstate, List *rte_path, Oid matviewid);
static void register_delta_ENRs(ParseState *pstate, Query *query, List *tables);
static char *make_delta_enr_name(const char *prefix, Oid relid, int count);
static RangeTblEntry *get_prestate_rte(RangeTblEntry *rte, MV_TriggerTable *table,
QueryEnvironment *queryEnv, Oid matviewid);
static RangeTblEntry *union_ENRs(RangeTblEntry *rte, Oid relid, List *enr_rtes, const char *prefix,
QueryEnvironment *queryEnv);
static Query *rewrite_query_for_distinct_and_aggregates(Query *query, ParseState *pstate);
static void calc_delta(MV_TriggerTable *table, List *rte_path, Query *query,
DestReceiver *dest_old, DestReceiver *dest_new,
TupleDesc *tupdesc_old, TupleDesc *tupdesc_new,
QueryEnvironment *queryEnv);
static Query *rewrite_query_for_postupdate_state(Query *query, MV_TriggerTable *table, List *rte_path);
static ListCell *getRteListCell(Query *query, List *rte_path);
static void apply_delta(Oid matviewOid, Tuplestorestate *old_tuplestores, Tuplestorestate *new_tuplestores,
TupleDesc tupdesc_old, TupleDesc tupdesc_new,
Query *query, bool use_count, char *count_colname);
static void append_set_clause_for_count(const char *resname, StringInfo buf_old,
StringInfo buf_new,StringInfo aggs_list);
static void append_set_clause_for_sum(const char *resname, StringInfo buf_old,
StringInfo buf_new, StringInfo aggs_list);
static void append_set_clause_for_avg(const char *resname, StringInfo buf_old,
StringInfo buf_new, StringInfo aggs_list,
const char *aggtype);
static void append_set_clause_for_minmax(const char *resname, StringInfo buf_old,
StringInfo buf_new, StringInfo aggs_list,
bool is_min);
static char *get_operation_string(IvmOp op, const char *col, const char *arg1, const char *arg2,
const char* count_col, const char *castType);
static char *get_null_condition_string(IvmOp op, const char *arg1, const char *arg2,
const char* count_col);
static void apply_old_delta(const char *matviewname, const char *deltaname_old,
List *keys);
static void apply_old_delta_with_count(const char *matviewname, const char *deltaname_old,
List *keys, StringInfo aggs_list, StringInfo aggs_set,
List *minmax_list, List *is_min_list,
const char *count_colname,
SPITupleTable **tuptable_recalc, uint64 *num_recalc);
static void apply_new_delta(const char *matviewname, const char *deltaname_new,
StringInfo target_list);
static void apply_new_delta_with_count(const char *matviewname, const char* deltaname_new,
List *keys, StringInfo target_list, StringInfo aggs_set,
const char* count_colname, bool distinct);
static char *get_matching_condition_string(List *keys);
static char *get_returning_string(List *minmax_list, List *is_min_list, List *keys);
static char *get_minmax_recalc_condition_string(List *minmax_list, List *is_min_list);
static char *get_select_for_recalc_string(List *keys);
static void recalc_and_set_values(SPITupleTable *tuptable_recalc, int64 num_tuples,
List *namelist, List *keys, Relation matviewRel);
static SPIPlanPtr get_plan_for_recalc(Relation matviewRel, List *namelist, List *keys, Oid *keyTypes);
static SPIPlanPtr get_plan_for_set_values(Relation matviewRel, List *namelist, Oid *valTypes);
static void generate_equal(StringInfo querybuf, Oid opttype,
const char *leftop, const char *rightop);
static void mv_InitHashTables(void);
static SPIPlanPtr mv_FetchPreparedPlan(MV_QueryKey *key);
static void mv_HashPreparedPlan(MV_QueryKey *key, SPIPlanPtr plan);
static void mv_BuildQueryKey(MV_QueryKey *key, Oid matview_id, int32 query_type);
static void clean_up_IVM_hash_entry(MV_TriggerHashEntry *entry, bool is_abort);
/* SQL callable functions */
PG_FUNCTION_INFO_V1(IVM_immediate_before);
PG_FUNCTION_INFO_V1(IVM_immediate_maintenance);
PG_FUNCTION_INFO_V1(ivm_visible_in_prestate);
/*
* ExecRefreshImmv -- execute a refresh_immv() function
*
* This imitates PostgreSQL's ExecRefreshMatView().
*/
ObjectAddress
ExecRefreshImmv(const RangeVar *relation, bool skipData,
const char *queryString, QueryCompletion *qc)
{
Oid matviewOid;
LOCKMODE lockmode;
/* Determine strength of lock needed. */
//concurrent = stmt->concurrent;
//lockmode = concurrent ? ExclusiveLock : AccessExclusiveLock;
lockmode = AccessExclusiveLock;
/*
* Get a lock until end of transaction.
*/
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM < 170000)
matviewOid = RangeVarGetRelidExtended(relation,
lockmode, 0,
RangeVarCallbackOwnsTable,
NULL);
#else
matviewOid = RangeVarGetRelidExtended(relation,
lockmode, 0,
RangeVarCallbackMaintainsTable,
NULL);
#endif
return RefreshImmvByOid(matviewOid, skipData, queryString, qc);
}
/*
* RefreshMatViewByOid -- refresh IMMV view by OID
*
* This imitates PostgreSQL's RefreshMatViewByOid().
*/
ObjectAddress
RefreshImmvByOid(Oid matviewOid, bool skipData,
const char *queryString, QueryCompletion *qc)
{
Relation matviewRel;
Query *dataQuery = NULL; /* initialized to keep compiler happy */
Query *viewQuery;
Oid tableSpace;
Oid relowner;
Oid OIDNewHeap;
DestReceiver *dest;
uint64 processed = 0;
char relpersistence;
Oid save_userid;
int save_sec_context;
int save_nestlevel;
ObjectAddress address;
bool oldPopulated;
Relation pgIvmImmv;
TupleDesc tupdesc;
ScanKeyData key;
SysScanDesc scan;
HeapTuple tup;
bool isnull;
Datum datum;
matviewRel = table_open(matviewOid, NoLock);
relowner = matviewRel->rd_rel->relowner;
/*
* Switch to the owner's userid, so that any functions are run as that
* user. Also lock down security-restricted operations and arrange to
* make GUC variable changes local to this command.
*/
GetUserIdAndSecContext(&save_userid, &save_sec_context);
SetUserIdAndSecContext(relowner,
save_sec_context | SECURITY_RESTRICTED_OPERATION);
save_nestlevel = NewGUCNestLevel();
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 170000)
RestrictSearchPath();
#endif
/*
* Make sure it is an IMMV:
* Get the entry in pg_ivm_immv. If it doesn't exist, the relation
* is not IMMV.
*/
pgIvmImmv = table_open(PgIvmImmvRelationId(), RowExclusiveLock);
tupdesc = RelationGetDescr(pgIvmImmv);
ScanKeyInit(&key,
Anum_pg_ivm_immv_immvrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(matviewRel)));
scan = systable_beginscan(pgIvmImmv, PgIvmImmvPrimaryKeyIndexId(),
true, NULL, 1, &key);
tup = systable_getnext(scan);
if (!HeapTupleIsValid(tup))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("\"%s\" is not an IMMV",
RelationGetRelationName(matviewRel))));
datum = heap_getattr(tup, Anum_pg_ivm_immv_ispopulated, tupdesc, &isnull);
Assert(!isnull);
oldPopulated = DatumGetBool(datum);
/*
* Check for active uses of the relation in the current transaction, such
* as open scans.
*
* NB: We count on this to protect us against problems with refreshing the
* data using TABLE_INSERT_FROZEN.
*/
CheckTableNotInUse(matviewRel, "refresh an IMMV");
/* Tentatively mark the IMMV as populated or not (this will roll back
* if we fail later).
*/
if (skipData != (!oldPopulated))
{
Datum values[Natts_pg_ivm_immv];
bool nulls[Natts_pg_ivm_immv];
bool replaces[Natts_pg_ivm_immv];
HeapTuple newtup = NULL;
memset(values, 0, sizeof(values));
values[Anum_pg_ivm_immv_ispopulated -1 ] = BoolGetDatum(!skipData);
MemSet(nulls, false, sizeof(nulls));
MemSet(replaces, false, sizeof(replaces));
replaces[Anum_pg_ivm_immv_ispopulated -1 ] = true;
newtup = heap_modify_tuple(tup, tupdesc, values, nulls, replaces);
CatalogTupleUpdate(pgIvmImmv, &newtup->t_self, newtup);
heap_freetuple(newtup);
/*
* Advance command counter to make the updated pg_ivm_immv row locally
* visible.
*/
CommandCounterIncrement();
}
systable_endscan(scan);
table_close(pgIvmImmv, NoLock);
viewQuery = get_immv_query(matviewRel);
/* For IMMV, we need to rewrite matview query */
if (!skipData)
dataQuery = rewriteQueryForIMMV(viewQuery,NIL);
tableSpace = matviewRel->rd_rel->reltablespace;
relpersistence = matviewRel->rd_rel->relpersistence;
/* delete IMMV triggers. */
if (skipData)
{
Relation tgRel;
Relation depRel;
ObjectAddresses *immv_triggers;
immv_triggers = new_object_addresses();
tgRel = table_open(TriggerRelationId, RowExclusiveLock);
depRel = table_open(DependRelationId, RowExclusiveLock);
/* search triggers that depends on IMMV. */
ScanKeyInit(&key,
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(matviewOid));
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
NULL, 1, &key);
while ((tup = systable_getnext(scan)) != NULL)
{
ObjectAddress obj;
Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
if (foundDep->classid == TriggerRelationId)
{
HeapTuple tgtup;
ScanKeyData tgkey[1];
SysScanDesc tgscan;
Form_pg_trigger tgform;
/* Find the trigger name. */
ScanKeyInit(&tgkey[0],
Anum_pg_trigger_oid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(foundDep->objid));
tgscan = systable_beginscan(tgRel, TriggerOidIndexId, true,
NULL, 1, tgkey);
tgtup = systable_getnext(tgscan);
if (!HeapTupleIsValid(tgtup))
elog(ERROR, "could not find tuple for immv trigger %u", foundDep->objid);
tgform = (Form_pg_trigger) GETSTRUCT(tgtup);
/* If trigger is created by IMMV, delete it. */
if (strncmp(NameStr(tgform->tgname), "IVM_trigger_", 12) == 0)
{
obj.classId = foundDep->classid;
obj.objectId = foundDep->objid;
obj.objectSubId = foundDep->refobjsubid;
add_exact_object_address(&obj, immv_triggers);
}
systable_endscan(tgscan);
}
}
systable_endscan(scan);
performMultipleDeletions(immv_triggers, DROP_RESTRICT, PERFORM_DELETION_INTERNAL);
table_close(depRel, RowExclusiveLock);
table_close(tgRel, RowExclusiveLock);
free_object_addresses(immv_triggers);
}
/*
* Create the transient table that will receive the regenerated data. Lock
* it against access by any other process until commit (by which time it
* will be gone).
*/
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 150000)
OIDNewHeap = make_new_heap(matviewOid, tableSpace,
matviewRel->rd_rel->relam, relpersistence, ExclusiveLock);
#else
OIDNewHeap = make_new_heap(matviewOid, tableSpace,
relpersistence, ExclusiveLock);
#endif
LockRelationOid(OIDNewHeap, AccessExclusiveLock);
dest = CreateTransientRelDestReceiver(OIDNewHeap);
/* Generate the data, if wanted. */
if (!skipData)
processed = refresh_immv_datafill(dest, dataQuery, NULL, NULL, queryString);
/* Make the matview match the newly generated data. */
refresh_by_heap_swap(matviewOid, OIDNewHeap, relpersistence);
/*
* Inform cumulative stats system about our activity: basically, we
* truncated the matview and inserted some new data. (The concurrent
* code path above doesn't need to worry about this because the
* inserts and deletes it issues get counted by lower-level code.)
*/
pgstat_count_truncate(matviewRel);
if (!skipData)
pgstat_count_heap_insert(matviewRel, processed);
/*
* Create triggers on incremental maintainable materialized view
* This argument should use 'dataQuery'. This needs to use a rewritten query,
* because a sublink in jointree is not supported by this function.
*/
if (!skipData && !oldPopulated)
CreateIvmTriggersOnBaseTables(dataQuery, matviewOid);
table_close(matviewRel, NoLock);
/* Roll back any GUC changes */
AtEOXact_GUC(false, save_nestlevel);
/* Restore userid and security context */
SetUserIdAndSecContext(save_userid, save_sec_context);
ObjectAddressSet(address, RelationRelationId, matviewOid);
/*
* Save the rowcount so that pg_stat_statements can track the total number
* of rows processed by REFRESH MATERIALIZED VIEW command. Note that we
* still don't display the rowcount in the command completion tag output,
* i.e., the display_rowcount flag of CMDTAG_REFRESH_MATERIALIZED_VIEW
* command tag is left false in cmdtaglist.h. Otherwise, the change of
* completion tag output might break applications using it.
*/
if (qc)
SetQueryCompletion(qc, CMDTAG_REFRESH_MATERIALIZED_VIEW, processed);
return address;
}
/*
* refresh_immv_datafill
*
* Execute the given query, sending result rows to "dest" (which will
* insert them into the target matview).
*
* Returns number of rows inserted.
*/
static uint64
refresh_immv_datafill(DestReceiver *dest, Query *query,
QueryEnvironment *queryEnv,
TupleDesc *resultTupleDesc,
const char *queryString)
{
List *rewritten;
PlannedStmt *plan;
QueryDesc *queryDesc;
Query *copied_query;
uint64 processed;
/* Lock and rewrite, using a copy to preserve the original query. */
copied_query = copyObject(query);
AcquireRewriteLocks(copied_query, true, false);
rewritten = QueryRewrite(copied_query);
/* SELECT should never rewrite to more or less than one SELECT query */
if (list_length(rewritten) != 1)
elog(ERROR, "unexpected rewrite result for REFRESH MATERIALIZED VIEW");
query = (Query *) linitial(rewritten);
/* Check for user-requested abort. */
CHECK_FOR_INTERRUPTS();
/* Plan the query which will generate data for the refresh. */
plan = pg_plan_query(query, queryString, CURSOR_OPT_PARALLEL_OK, NULL);
/*
* Use a snapshot with an updated command ID to ensure this query sees
* results of any previously executed queries. (This could only matter if
* the planner executed an allegedly-stable function that changed the
* database contents, but let's do it anyway to be safe.)
*/
PushCopiedSnapshot(GetActiveSnapshot());
UpdateActiveSnapshotCommandId();
/* Create a QueryDesc, redirecting output to our tuple receiver */
queryDesc = CreateQueryDesc(plan, queryString,
GetActiveSnapshot(), InvalidSnapshot,
dest, NULL, queryEnv ? queryEnv: NULL, 0);
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, 0);
/* run the plan */
ExecutorRun(queryDesc, ForwardScanDirection, 0, true);
processed = queryDesc->estate->es_processed;
if (resultTupleDesc)
*resultTupleDesc = CreateTupleDescCopy(queryDesc->tupDesc);
/* and clean up */
ExecutorFinish(queryDesc);
ExecutorEnd(queryDesc);
FreeQueryDesc(queryDesc);
PopActiveSnapshot();
return processed;
}
/*
* Swap the physical files of the target and transient tables, then rebuild
* the target's indexes and throw away the transient table. Security context
* swapping is handled by the called function, so it is not needed here.
*/
static void
refresh_by_heap_swap(Oid matviewOid, Oid OIDNewHeap, char relpersistence)
{
finish_heap_swap(matviewOid, OIDNewHeap, false, false, true, true,
RecentXmin, ReadNextMultiXactId(), relpersistence);
}
/*
* This should be used to test whether the backend is in a context where it is
* OK to allow DML statements to modify IMMVs. We only want to
* allow that for internal code driven by the IMMV definition,
* not for arbitrary user-supplied code.
*/
bool
ImmvIncrementalMaintenanceIsEnabled(void)
{
return immv_maintenance_depth > 0;
}
static void
OpenImmvIncrementalMaintenance(void)
{
immv_maintenance_depth++;
}
static void
CloseImmvIncrementalMaintenance(void)
{
immv_maintenance_depth--;
Assert(immv_maintenance_depth >= 0);
}
/*
* get_immv_query - get the Query of IMMV.
*/
Query *
get_immv_query(Relation matviewRel)
{
Relation pgIvmImmv = table_open(PgIvmImmvRelationId(), AccessShareLock);
TupleDesc tupdesc = RelationGetDescr(pgIvmImmv);
SysScanDesc scan;
ScanKeyData key;
HeapTuple tup;
bool isnull;
Datum datum;
Query *query;
ScanKeyInit(&key,
Anum_pg_ivm_immv_immvrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(matviewRel)));
scan = systable_beginscan(pgIvmImmv, PgIvmImmvPrimaryKeyIndexId(),
true, NULL, 1, &key);
tup = systable_getnext(scan);
if (!HeapTupleIsValid(tup))
{
systable_endscan(scan);
table_close(pgIvmImmv, NoLock);
return NULL;
}
datum = heap_getattr(tup, Anum_pg_ivm_immv_viewdef, tupdesc, &isnull);
Assert(!isnull);
query = (Query *) stringToNode(TextDatumGetCString(datum));
systable_endscan(scan);
table_close(pgIvmImmv, NoLock);
return query;
}
static Tuplestorestate *
tuplestore_copy(Tuplestorestate *tuplestore, Relation rel)
{
Tuplestorestate *res = NULL;
TupleDesc tupdesc = RelationGetDescr(rel);
TupleTableSlot *slot = MakeSingleTupleTableSlot(tupdesc, &TTSOpsMinimalTuple);
tuplestore_rescan(tuplestore);
res = tuplestore_begin_heap(false, false, work_mem);
while (tuplestore_gettupleslot(tuplestore, true, false, slot))
tuplestore_puttupleslot(res, slot);
ExecDropSingleTupleTableSlot(slot);
return res;
}
/* ----------------------------------------------------
* Incremental View Maintenance routines
* ---------------------------------------------------
*/
/*
* IVM_immediate_before
*
* IVM trigger function invoked before base table is modified. If this is
* invoked firstly in the same statement, we save the transaction id and the
* command id at that time.
*/
Datum
IVM_immediate_before(PG_FUNCTION_ARGS)
{
TriggerData *trigdata = (TriggerData *) fcinfo->context;
char *matviewOid_text = trigdata->tg_trigger->tgargs[0];
char *ex_lock_text = trigdata->tg_trigger->tgargs[1];
Oid matviewOid;
MV_TriggerHashEntry *entry;
bool found;
bool ex_lock;
matviewOid = DatumGetObjectId(DirectFunctionCall1(oidin, CStringGetDatum(matviewOid_text)));
ex_lock = DatumGetBool(DirectFunctionCall1(boolin, CStringGetDatum(ex_lock_text)));
/* If the view has more than one tables, we have to use an exclusive lock. */
if (ex_lock)
{
/*
* Wait for concurrent transactions which update this materialized view at
* READ COMMITED. This is needed to see changes committed in other
* transactions. No wait and raise an error at REPEATABLE READ or
* SERIALIZABLE to prevent update anomalies of matviews.
* XXX: dead-lock is possible here.
*/
if (!IsolationUsesXactSnapshot())
LockRelationOid(matviewOid, ExclusiveLock);
else if (!ConditionalLockRelationOid(matviewOid, ExclusiveLock))
{
/* try to throw error by name; relation could be deleted... */
char *relname = get_rel_name(matviewOid);
if (!relname)
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on materialized view during incremental maintenance")));
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on materialized view \"%s\" during incremental maintenance",
relname)));
}
}
else
LockRelationOid(matviewOid, RowExclusiveLock);
/*
* On the first call initialize the hashtable
*/
if (!mv_trigger_info)
mv_InitHashTables();
entry = (MV_TriggerHashEntry *) hash_search(mv_trigger_info,
(void *) &matviewOid,
HASH_ENTER, &found);
/* On the first BEFORE to update the view, initialize trigger data */
if (!found)
{
/*
* Get a snapshot just before the table was modified for checking
* tuple visibility in the pre-update state of the table.
*/
Snapshot snapshot = GetActiveSnapshot();
entry->matview_id = matviewOid;
entry->before_trig_count = 0;
entry->after_trig_count = 0;
entry->snapshot = RegisterSnapshot(snapshot);
entry->tables = NIL;
entry->has_old = false;
entry->has_new = false;
}
entry->before_trig_count++;
return PointerGetDatum(NULL);
}
/*
* IVM_immediate_maintenance
*
* IVM trigger function invoked after base table is modified.
* For each table, tuplestores of transition tables are collected.
* and after the last modification
*/
Datum
IVM_immediate_maintenance(PG_FUNCTION_ARGS)
{
TriggerData *trigdata = (TriggerData *) fcinfo->context;
Relation rel;
Oid relid;
Oid matviewOid;
Query *query;
Query *rewritten = NULL;
char *matviewOid_text = trigdata->tg_trigger->tgargs[0];
Relation matviewRel;
int old_depth = immv_maintenance_depth;
Oid relowner;
Tuplestorestate *old_tuplestore = NULL;
Tuplestorestate *new_tuplestore = NULL;
DestReceiver *dest_new = NULL, *dest_old = NULL;
Oid save_userid;
int save_sec_context;
int save_nestlevel;
MV_TriggerHashEntry *entry;
MV_TriggerTable *table;
bool found;
ParseState *pstate;
QueryEnvironment *queryEnv = create_queryEnv();
MemoryContext oldcxt;
ListCell *lc;
int i;
/* Create a ParseState for rewriting the view definition query */
pstate = make_parsestate(NULL);
pstate->p_queryEnv = queryEnv;
pstate->p_expr_kind = EXPR_KIND_SELECT_TARGET;
rel = trigdata->tg_relation;
relid = rel->rd_id;
matviewOid = DatumGetObjectId(DirectFunctionCall1(oidin, CStringGetDatum(matviewOid_text)));
/*
* On the first call initialize the hashtable
*/
if (!mv_trigger_info)
mv_InitHashTables();
/* get the entry for this materialized view */
entry = (MV_TriggerHashEntry *) hash_search(mv_trigger_info,
(void *) &matviewOid,
HASH_FIND, &found);
Assert (found && entry != NULL);
entry->after_trig_count++;
/* search the entry for the modified table and create new entry if not found */
found = false;
foreach(lc, entry->tables)
{
table = (MV_TriggerTable *) lfirst(lc);
if (table->table_id == relid)
{
found = true;
break;
}
}
if (!found)
{
oldcxt = MemoryContextSwitchTo(TopTransactionContext);
table = (MV_TriggerTable *) palloc0(sizeof(MV_TriggerTable));
table->table_id = relid;
table->old_tuplestores = NIL;
table->new_tuplestores = NIL;
table->old_rtes = NIL;
table->new_rtes = NIL;
table->rte_paths = NIL;
table->slot = MakeSingleTupleTableSlot(RelationGetDescr(rel), table_slot_callbacks(rel));
table->rel = table_open(RelationGetRelid(rel), NoLock);
entry->tables = lappend(entry->tables, table);
MemoryContextSwitchTo(oldcxt);
}
/* Save the transition tables and make a request to not free immediately */
if (trigdata->tg_oldtable)
{
oldcxt = MemoryContextSwitchTo(TopTransactionContext);
table->old_tuplestores = lappend(table->old_tuplestores, tuplestore_copy(trigdata->tg_oldtable, rel));
entry->has_old = true;
MemoryContextSwitchTo(oldcxt);
}
if (trigdata->tg_newtable)
{
oldcxt = MemoryContextSwitchTo(TopTransactionContext);
table->new_tuplestores = lappend(table->new_tuplestores, tuplestore_copy(trigdata->tg_newtable, rel));
entry->has_new = true;
MemoryContextSwitchTo(oldcxt);
}
/* If this is not the last AFTER trigger call, immediately exit. */
Assert (entry->before_trig_count >= entry->after_trig_count);
if (entry->before_trig_count != entry->after_trig_count)
return PointerGetDatum(NULL);
/*
* If this is the last AFTER trigger call, continue and update the view.
*/
/*
* Advance command counter to make the updated base table row locally
* visible.
*/
CommandCounterIncrement();
matviewRel = table_open(matviewOid, NoLock);
/* Make sure IMMV is a table. */
Assert(matviewRel->rd_rel->relkind == RELKIND_RELATION);
/*
* Get and push the latast snapshot to see any changes which is committed
* during waiting in other transactions at READ COMMITTED level.
*/
PushActiveSnapshot(GetTransactionSnapshot());
/*
* Check for active uses of the relation in the current transaction, such
* as open scans.
*
* NB: We count on this to protect us against problems with refreshing the
* data using TABLE_INSERT_FROZEN.
*/
CheckTableNotInUse(matviewRel, "refresh an IMMV incrementally");
/*
* Switch to the owner's userid, so that any functions are run as that
* user. Also arrange to make GUC variable changes local to this command.
* We will switch modes when we are about to execute user code.
*/
relowner = matviewRel->rd_rel->relowner;
GetUserIdAndSecContext(&save_userid, &save_sec_context);
SetUserIdAndSecContext(relowner,
save_sec_context | SECURITY_RESTRICTED_OPERATION);
save_nestlevel = NewGUCNestLevel();
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 170000)
RestrictSearchPath();
#endif
/* get view query*/
query = get_immv_query(matviewRel);
/*
* When a base table is truncated, the view content will be empty if the
* view definition query does not contain an aggregate without a GROUP clause.
* Therefore, such views can be truncated.
*
* Aggregate views without a GROUP clause always have one row. Therefore,
* if a base table is truncated, the view will not be empty and will contain
* a row with NULL value (or 0 for count()). So, in this case, we refresh the
* view instead of truncating it.
*/
if (TRIGGER_FIRED_BY_TRUNCATE(trigdata->tg_event))
{
if (!(query->hasAggs && query->groupClause == NIL))
{
OpenImmvIncrementalMaintenance();
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 160000)
ExecuteTruncateGuts(list_make1(matviewRel), list_make1_oid(matviewOid),
NIL, DROP_RESTRICT, false, false);
#else
ExecuteTruncateGuts(list_make1(matviewRel), list_make1_oid(matviewOid),
NIL, DROP_RESTRICT, false);
#endif
CloseImmvIncrementalMaintenance();
}
else
{
Oid OIDNewHeap;
DestReceiver *dest;
uint64 processed = 0;
Query *dataQuery = rewriteQueryForIMMV(query, NIL);
char relpersistence = matviewRel->rd_rel->relpersistence;
/*
* Create the transient table that will receive the regenerated data. Lock
* it against access by any other process until commit (by which time it
* will be gone).
*/
#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 150000)
OIDNewHeap = make_new_heap(matviewOid, matviewRel->rd_rel->reltablespace,
matviewRel->rd_rel->relam, relpersistence, ExclusiveLock);
#else
OIDNewHeap = make_new_heap(matviewOid, matviewRel->rd_rel->reltablespace,
relpersistence, ExclusiveLock);
#endif
LockRelationOid(OIDNewHeap, AccessExclusiveLock);
dest = CreateTransientRelDestReceiver(OIDNewHeap);
/* Generate the data */
processed = refresh_immv_datafill(dest, dataQuery, NULL, NULL, "");
refresh_by_heap_swap(matviewOid, OIDNewHeap, relpersistence);
/* Inform cumulative stats system about our activity */
pgstat_count_truncate(matviewRel);
pgstat_count_heap_insert(matviewRel, processed);
}
/* Clean up hash entry and delete tuplestores */
clean_up_IVM_hash_entry(entry, false);
/* Pop the original snapshot. */
PopActiveSnapshot();
table_close(matviewRel, NoLock);
/* Roll back any GUC changes */
AtEOXact_GUC(false, save_nestlevel);
/* Restore userid and security context */
SetUserIdAndSecContext(save_userid, save_sec_context);
return PointerGetDatum(NULL);
}