/*------------------------------------------------------------------------- * * subscriptioncmds.c * subscription catalog manipulation functions * * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION * subscriptioncmds.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/htup_details.h" #include "access/table.h" #include "access/xact.h" #include "catalog/catalog.h" #include "catalog/dependency.h" #include "catalog/indexing.h" #include "catalog/namespace.h" #include "catalog/objectaccess.h" #include "catalog/objectaddress.h" #include "catalog/pg_subscription.h" #include "catalog/pg_subscription_rel.h" #include "catalog/pg_type.h" #include "commands/defrem.h" #include "commands/event_trigger.h" #include "commands/subscriptioncmds.h" #include "executor/executor.h" #include "miscadmin.h" #include "nodes/makefuncs.h" #include "replication/logicallauncher.h" #include "replication/origin.h" #include "replication/slot.h" #include "replication/walreceiver.h" #include "replication/walsender.h" #include "replication/worker_internal.h" #include "storage/lmgr.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/guc.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/syscache.h" static List *fetch_table_list(WalReceiverConn *wrconn, List *publications); static void ReportSlotConnectionError(List *rstates, Oid subid, char *slotname, char *err); /* * Common option parsing function for CREATE and ALTER SUBSCRIPTION commands. * * Since not all options can be specified in both commands, this function * will report an error on options if the target output pointer is NULL to * accommodate that. */ static void parse_subscription_options(List *options, bool *connect, bool *enabled_given, bool *enabled, bool *create_slot, bool *slot_name_given, char **slot_name, bool *copy_data, char **synchronous_commit, bool *refresh, bool *binary_given, bool *binary, bool *streaming_given, bool *streaming) { ListCell *lc; bool connect_given = false; bool create_slot_given = false; bool copy_data_given = false; bool refresh_given = false; /* If connect is specified, the others also need to be. */ Assert(!connect || (enabled && create_slot && copy_data)); if (connect) *connect = true; if (enabled) { *enabled_given = false; *enabled = true; } if (create_slot) *create_slot = true; if (slot_name) { *slot_name_given = false; *slot_name = NULL; } if (copy_data) *copy_data = true; if (synchronous_commit) *synchronous_commit = NULL; if (refresh) *refresh = true; if (binary) { *binary_given = false; *binary = false; } if (streaming) { *streaming_given = false; *streaming = false; } /* Parse options */ foreach(lc, options) { DefElem *defel = (DefElem *) lfirst(lc); if (strcmp(defel->defname, "connect") == 0 && connect) { if (connect_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); connect_given = true; *connect = defGetBoolean(defel); } else if (strcmp(defel->defname, "enabled") == 0 && enabled) { if (*enabled_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); *enabled_given = true; *enabled = defGetBoolean(defel); } else if (strcmp(defel->defname, "create_slot") == 0 && create_slot) { if (create_slot_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); create_slot_given = true; *create_slot = defGetBoolean(defel); } else if (strcmp(defel->defname, "slot_name") == 0 && slot_name) { if (*slot_name_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); *slot_name_given = true; *slot_name = defGetString(defel); /* Setting slot_name = NONE is treated as no slot name. */ if (strcmp(*slot_name, "none") == 0) *slot_name = NULL; } else if (strcmp(defel->defname, "copy_data") == 0 && copy_data) { if (copy_data_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); copy_data_given = true; *copy_data = defGetBoolean(defel); } else if (strcmp(defel->defname, "synchronous_commit") == 0 && synchronous_commit) { if (*synchronous_commit) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); *synchronous_commit = defGetString(defel); /* Test if the given value is valid for synchronous_commit GUC. */ (void) set_config_option("synchronous_commit", *synchronous_commit, PGC_BACKEND, PGC_S_TEST, GUC_ACTION_SET, false, 0, false); } else if (strcmp(defel->defname, "refresh") == 0 && refresh) { if (refresh_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); refresh_given = true; *refresh = defGetBoolean(defel); } else if (strcmp(defel->defname, "binary") == 0 && binary) { if (*binary_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); *binary_given = true; *binary = defGetBoolean(defel); } else if (strcmp(defel->defname, "streaming") == 0 && streaming) { if (*streaming_given) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("conflicting or redundant options"))); *streaming_given = true; *streaming = defGetBoolean(defel); } else ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("unrecognized subscription parameter: \"%s\"", defel->defname))); } /* * We've been explicitly asked to not connect, that requires some * additional processing. */ if (connect && !*connect) { /* Check for incompatible options from the user. */ if (enabled && *enabled_given && *enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), /*- translator: both %s are strings of the form "option = value" */ errmsg("%s and %s are mutually exclusive options", "connect = false", "enabled = true"))); if (create_slot && create_slot_given && *create_slot) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("%s and %s are mutually exclusive options", "connect = false", "create_slot = true"))); if (copy_data && copy_data_given && *copy_data) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("%s and %s are mutually exclusive options", "connect = false", "copy_data = true"))); /* Change the defaults of other options. */ *enabled = false; *create_slot = false; *copy_data = false; } /* * Do additional checking for disallowed combination when slot_name = NONE * was used. */ if (slot_name && *slot_name_given && !*slot_name) { if (enabled && *enabled_given && *enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), /*- translator: both %s are strings of the form "option = value" */ errmsg("%s and %s are mutually exclusive options", "slot_name = NONE", "enabled = true"))); if (create_slot && create_slot_given && *create_slot) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("%s and %s are mutually exclusive options", "slot_name = NONE", "create_slot = true"))); if (enabled && !*enabled_given && *enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), /*- translator: both %s are strings of the form "option = value" */ errmsg("subscription with %s must also set %s", "slot_name = NONE", "enabled = false"))); if (create_slot && !create_slot_given && *create_slot) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("subscription with %s must also set %s", "slot_name = NONE", "create_slot = false"))); } } /* * Auxiliary function to build a text array out of a list of String nodes. */ static Datum publicationListToArray(List *publist) { ArrayType *arr; Datum *datums; int j = 0; ListCell *cell; MemoryContext memcxt; MemoryContext oldcxt; /* Create memory context for temporary allocations. */ memcxt = AllocSetContextCreate(CurrentMemoryContext, "publicationListToArray to array", ALLOCSET_DEFAULT_SIZES); oldcxt = MemoryContextSwitchTo(memcxt); datums = (Datum *) palloc(sizeof(Datum) * list_length(publist)); foreach(cell, publist) { char *name = strVal(lfirst(cell)); ListCell *pcell; /* Check for duplicates. */ foreach(pcell, publist) { char *pname = strVal(lfirst(pcell)); if (pcell == cell) break; if (strcmp(name, pname) == 0) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("publication name \"%s\" used more than once", pname))); } datums[j++] = CStringGetTextDatum(name); } MemoryContextSwitchTo(oldcxt); arr = construct_array(datums, list_length(publist), TEXTOID, -1, false, TYPALIGN_INT); MemoryContextDelete(memcxt); return PointerGetDatum(arr); } /* * Create new subscription. */ ObjectAddress CreateSubscription(CreateSubscriptionStmt *stmt, bool isTopLevel) { Relation rel; ObjectAddress myself; Oid subid; bool nulls[Natts_pg_subscription]; Datum values[Natts_pg_subscription]; Oid owner = GetUserId(); HeapTuple tup; bool connect; bool enabled_given; bool enabled; bool copy_data; bool streaming; bool streaming_given; char *synchronous_commit; char *conninfo; char *slotname; bool slotname_given; bool binary; bool binary_given; char originname[NAMEDATALEN]; bool create_slot; List *publications; /* * Parse and check options. * * Connection and publication should not be specified here. */ parse_subscription_options(stmt->options, &connect, &enabled_given, &enabled, &create_slot, &slotname_given, &slotname, ©_data, &synchronous_commit, NULL, /* no "refresh" */ &binary_given, &binary, &streaming_given, &streaming); /* * Since creating a replication slot is not transactional, rolling back * the transaction leaves the created replication slot. So we cannot run * CREATE SUBSCRIPTION inside a transaction block if creating a * replication slot. */ if (create_slot) PreventInTransactionBlock(isTopLevel, "CREATE SUBSCRIPTION ... WITH (create_slot = true)"); if (!superuser()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("must be superuser to create subscriptions"))); /* * If built with appropriate switch, whine when regression-testing * conventions for subscription names are violated. */ #ifdef ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS if (strncmp(stmt->subname, "regress_", 8) != 0) elog(WARNING, "subscriptions created by regression test cases should have names starting with \"regress_\""); #endif rel = table_open(SubscriptionRelationId, RowExclusiveLock); /* Check if name is used */ subid = GetSysCacheOid2(SUBSCRIPTIONNAME, Anum_pg_subscription_oid, MyDatabaseId, CStringGetDatum(stmt->subname)); if (OidIsValid(subid)) { ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("subscription \"%s\" already exists", stmt->subname))); } if (!slotname_given && slotname == NULL) slotname = stmt->subname; /* The default for synchronous_commit of subscriptions is off. */ if (synchronous_commit == NULL) synchronous_commit = "off"; conninfo = stmt->conninfo; publications = stmt->publication; /* Load the library providing us libpq calls. */ load_file("libpqwalreceiver", false); /* Check the connection info string. */ walrcv_check_conninfo(conninfo); /* Everything ok, form a new tuple. */ memset(values, 0, sizeof(values)); memset(nulls, false, sizeof(nulls)); subid = GetNewOidWithIndex(rel, SubscriptionObjectIndexId, Anum_pg_subscription_oid); values[Anum_pg_subscription_oid - 1] = ObjectIdGetDatum(subid); values[Anum_pg_subscription_subdbid - 1] = ObjectIdGetDatum(MyDatabaseId); values[Anum_pg_subscription_subname - 1] = DirectFunctionCall1(namein, CStringGetDatum(stmt->subname)); values[Anum_pg_subscription_subowner - 1] = ObjectIdGetDatum(owner); values[Anum_pg_subscription_subenabled - 1] = BoolGetDatum(enabled); values[Anum_pg_subscription_subbinary - 1] = BoolGetDatum(binary); values[Anum_pg_subscription_substream - 1] = BoolGetDatum(streaming); values[Anum_pg_subscription_subconninfo - 1] = CStringGetTextDatum(conninfo); if (slotname) values[Anum_pg_subscription_subslotname - 1] = DirectFunctionCall1(namein, CStringGetDatum(slotname)); else nulls[Anum_pg_subscription_subslotname - 1] = true; values[Anum_pg_subscription_subsynccommit - 1] = CStringGetTextDatum(synchronous_commit); values[Anum_pg_subscription_subpublications - 1] = publicationListToArray(publications); tup = heap_form_tuple(RelationGetDescr(rel), values, nulls); /* Insert tuple into catalog. */ CatalogTupleInsert(rel, tup); heap_freetuple(tup); recordDependencyOnOwner(SubscriptionRelationId, subid, owner); snprintf(originname, sizeof(originname), "pg_%u", subid); replorigin_create(originname); /* * Connect to remote side to execute requested commands and fetch table * info. */ if (connect) { char *err; WalReceiverConn *wrconn; List *tables; ListCell *lc; char table_state; /* Try to connect to the publisher. */ wrconn = walrcv_connect(conninfo, true, stmt->subname, &err); if (!wrconn) ereport(ERROR, (errmsg("could not connect to the publisher: %s", err))); PG_TRY(); { /* * Set sync state based on if we were asked to do data copy or * not. */ table_state = copy_data ? SUBREL_STATE_INIT : SUBREL_STATE_READY; /* * Get the table list from publisher and build local table status * info. */ tables = fetch_table_list(wrconn, publications); foreach(lc, tables) { RangeVar *rv = (RangeVar *) lfirst(lc); Oid relid; relid = RangeVarGetRelid(rv, AccessShareLock, false); /* Check for supported relkind. */ CheckSubscriptionRelkind(get_rel_relkind(relid), rv->schemaname, rv->relname); AddSubscriptionRelState(subid, relid, table_state, InvalidXLogRecPtr); } /* * If requested, create permanent slot for the subscription. We * won't use the initial snapshot for anything, so no need to * export it. */ if (create_slot) { Assert(slotname); walrcv_create_slot(wrconn, slotname, false, CRS_NOEXPORT_SNAPSHOT, NULL); ereport(NOTICE, (errmsg("created replication slot \"%s\" on publisher", slotname))); } } PG_FINALLY(); { walrcv_disconnect(wrconn); } PG_END_TRY(); } else ereport(WARNING, /* translator: %s is an SQL ALTER statement */ (errmsg("tables were not subscribed, you will have to run %s to subscribe the tables", "ALTER SUBSCRIPTION ... REFRESH PUBLICATION"))); table_close(rel, RowExclusiveLock); if (enabled) ApplyLauncherWakeupAtCommit(); ObjectAddressSet(myself, SubscriptionRelationId, subid); InvokeObjectPostCreateHook(SubscriptionRelationId, subid, 0); return myself; } static void AlterSubscription_refresh(Subscription *sub, bool copy_data) { char *err; List *pubrel_names; List *subrel_states; Oid *subrel_local_oids; Oid *pubrel_local_oids; ListCell *lc; int off; int remove_rel_len; Relation rel = NULL; typedef struct SubRemoveRels { Oid relid; char state; } SubRemoveRels; SubRemoveRels *sub_remove_rels; /* Load the library providing us libpq calls. */ load_file("libpqwalreceiver", false); PG_TRY(); { /* Try to connect to the publisher. */ wrconn = walrcv_connect(sub->conninfo, true, sub->name, &err); if (!wrconn) ereport(ERROR, (errmsg("could not connect to the publisher: %s", err))); /* Get the table list from publisher. */ pubrel_names = fetch_table_list(wrconn, sub->publications); /* Get local table list. */ subrel_states = GetSubscriptionRelations(sub->oid); /* * Build qsorted array of local table oids for faster lookup. This can * potentially contain all tables in the database so speed of lookup * is important. */ subrel_local_oids = palloc(list_length(subrel_states) * sizeof(Oid)); off = 0; foreach(lc, subrel_states) { SubscriptionRelState *relstate = (SubscriptionRelState *) lfirst(lc); subrel_local_oids[off++] = relstate->relid; } qsort(subrel_local_oids, list_length(subrel_states), sizeof(Oid), oid_cmp); /* * Rels that we want to remove from subscription and drop any slots * and origins corresponding to them. */ sub_remove_rels = palloc(list_length(subrel_states) * sizeof(SubRemoveRels)); /* * Walk over the remote tables and try to match them to locally known * tables. If the table is not known locally create a new state for * it. * * Also builds array of local oids of remote tables for the next step. */ off = 0; pubrel_local_oids = palloc(list_length(pubrel_names) * sizeof(Oid)); foreach(lc, pubrel_names) { RangeVar *rv = (RangeVar *) lfirst(lc); Oid relid; relid = RangeVarGetRelid(rv, AccessShareLock, false); /* Check for supported relkind. */ CheckSubscriptionRelkind(get_rel_relkind(relid), rv->schemaname, rv->relname); pubrel_local_oids[off++] = relid; if (!bsearch(&relid, subrel_local_oids, list_length(subrel_states), sizeof(Oid), oid_cmp)) { AddSubscriptionRelState(sub->oid, relid, copy_data ? SUBREL_STATE_INIT : SUBREL_STATE_READY, InvalidXLogRecPtr); ereport(DEBUG1, (errmsg_internal("table \"%s.%s\" added to subscription \"%s\"", rv->schemaname, rv->relname, sub->name))); } } /* * Next remove state for tables we should not care about anymore using * the data we collected above */ qsort(pubrel_local_oids, list_length(pubrel_names), sizeof(Oid), oid_cmp); remove_rel_len = 0; for (off = 0; off < list_length(subrel_states); off++) { Oid relid = subrel_local_oids[off]; if (!bsearch(&relid, pubrel_local_oids, list_length(pubrel_names), sizeof(Oid), oid_cmp)) { char state; XLogRecPtr statelsn; /* * Lock pg_subscription_rel with AccessExclusiveLock to * prevent any race conditions with the apply worker * re-launching workers at the same time this code is trying * to remove those tables. * * Even if new worker for this particular rel is restarted it * won't be able to make any progress as we hold exclusive * lock on subscription_rel till the transaction end. It will * simply exit as there is no corresponding rel entry. * * This locking also ensures that the state of rels won't * change till we are done with this refresh operation. */ if (!rel) rel = table_open(SubscriptionRelRelationId, AccessExclusiveLock); /* Last known rel state. */ state = GetSubscriptionRelState(sub->oid, relid, &statelsn); sub_remove_rels[remove_rel_len].relid = relid; sub_remove_rels[remove_rel_len++].state = state; RemoveSubscriptionRel(sub->oid, relid); logicalrep_worker_stop(sub->oid, relid); /* * For READY state, we would have already dropped the * tablesync origin. */ if (state != SUBREL_STATE_READY) { char originname[NAMEDATALEN]; /* * Drop the tablesync's origin tracking if exists. * * It is possible that the origin is not yet created for * tablesync worker, this can happen for the states before * SUBREL_STATE_FINISHEDCOPY. The apply worker can also * concurrently try to drop the origin and by this time * the origin might be already removed. For these reasons, * passing missing_ok = true. */ ReplicationOriginNameForTablesync(sub->oid, relid, originname, sizeof(originname)); replorigin_drop_by_name(originname, true, false); } ereport(DEBUG1, (errmsg_internal("table \"%s.%s\" removed from subscription \"%s\"", get_namespace_name(get_rel_namespace(relid)), get_rel_name(relid), sub->name))); } } /* * Drop the tablesync slots associated with removed tables. This has * to be at the end because otherwise if there is an error while doing * the database operations we won't be able to rollback dropped slots. */ for (off = 0; off < remove_rel_len; off++) { if (sub_remove_rels[off].state != SUBREL_STATE_READY && sub_remove_rels[off].state != SUBREL_STATE_SYNCDONE) { char syncslotname[NAMEDATALEN] = {0}; /* * For READY/SYNCDONE states we know the tablesync slot has * already been dropped by the tablesync worker. * * For other states, there is no certainty, maybe the slot * does not exist yet. Also, if we fail after removing some of * the slots, next time, it will again try to drop already * dropped slots and fail. For these reasons, we allow * missing_ok = true for the drop. */ ReplicationSlotNameForTablesync(sub->oid, sub_remove_rels[off].relid, syncslotname, sizeof(syncslotname)); ReplicationSlotDropAtPubNode(wrconn, syncslotname, true); } } } PG_FINALLY(); { if (wrconn) walrcv_disconnect(wrconn); } PG_END_TRY(); if (rel) table_close(rel, NoLock); } /* * Alter the existing subscription. */ ObjectAddress AlterSubscription(AlterSubscriptionStmt *stmt, bool isTopLevel) { Relation rel; ObjectAddress myself; bool nulls[Natts_pg_subscription]; bool replaces[Natts_pg_subscription]; Datum values[Natts_pg_subscription]; HeapTuple tup; Oid subid; bool update_tuple = false; Subscription *sub; Form_pg_subscription form; rel = table_open(SubscriptionRelationId, RowExclusiveLock); /* Fetch the existing tuple. */ tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, MyDatabaseId, CStringGetDatum(stmt->subname)); if (!HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("subscription \"%s\" does not exist", stmt->subname))); form = (Form_pg_subscription) GETSTRUCT(tup); subid = form->oid; /* must be owner */ if (!pg_subscription_ownercheck(subid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_SUBSCRIPTION, stmt->subname); sub = GetSubscription(subid, false); /* Lock the subscription so nobody else can do anything with it. */ LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock); /* Form a new tuple. */ memset(values, 0, sizeof(values)); memset(nulls, false, sizeof(nulls)); memset(replaces, false, sizeof(replaces)); switch (stmt->kind) { case ALTER_SUBSCRIPTION_OPTIONS: { char *slotname; bool slotname_given; char *synchronous_commit; bool binary_given; bool binary; bool streaming_given; bool streaming; parse_subscription_options(stmt->options, NULL, /* no "connect" */ NULL, NULL, /* no "enabled" */ NULL, /* no "create_slot" */ &slotname_given, &slotname, NULL, /* no "copy_data" */ &synchronous_commit, NULL, /* no "refresh" */ &binary_given, &binary, &streaming_given, &streaming); if (slotname_given) { if (sub->enabled && !slotname) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("cannot set %s for enabled subscription", "slot_name = NONE"))); if (slotname) values[Anum_pg_subscription_subslotname - 1] = DirectFunctionCall1(namein, CStringGetDatum(slotname)); else nulls[Anum_pg_subscription_subslotname - 1] = true; replaces[Anum_pg_subscription_subslotname - 1] = true; } if (synchronous_commit) { values[Anum_pg_subscription_subsynccommit - 1] = CStringGetTextDatum(synchronous_commit); replaces[Anum_pg_subscription_subsynccommit - 1] = true; } if (binary_given) { values[Anum_pg_subscription_subbinary - 1] = BoolGetDatum(binary); replaces[Anum_pg_subscription_subbinary - 1] = true; } if (streaming_given) { values[Anum_pg_subscription_substream - 1] = BoolGetDatum(streaming); replaces[Anum_pg_subscription_substream - 1] = true; } update_tuple = true; break; } case ALTER_SUBSCRIPTION_ENABLED: { bool enabled, enabled_given; parse_subscription_options(stmt->options, NULL, /* no "connect" */ &enabled_given, &enabled, NULL, /* no "create_slot" */ NULL, NULL, /* no "slot_name" */ NULL, /* no "copy_data" */ NULL, /* no "synchronous_commit" */ NULL, /* no "refresh" */ NULL, NULL, /* no "binary" */ NULL, NULL); /* no streaming */ Assert(enabled_given); if (!sub->slotname && enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("cannot enable subscription that does not have a slot name"))); values[Anum_pg_subscription_subenabled - 1] = BoolGetDatum(enabled); replaces[Anum_pg_subscription_subenabled - 1] = true; if (enabled) ApplyLauncherWakeupAtCommit(); update_tuple = true; break; } case ALTER_SUBSCRIPTION_CONNECTION: /* Load the library providing us libpq calls. */ load_file("libpqwalreceiver", false); /* Check the connection info string. */ walrcv_check_conninfo(stmt->conninfo); values[Anum_pg_subscription_subconninfo - 1] = CStringGetTextDatum(stmt->conninfo); replaces[Anum_pg_subscription_subconninfo - 1] = true; update_tuple = true; break; case ALTER_SUBSCRIPTION_PUBLICATION: { bool copy_data; bool refresh; parse_subscription_options(stmt->options, NULL, /* no "connect" */ NULL, NULL, /* no "enabled" */ NULL, /* no "create_slot" */ NULL, NULL, /* no "slot_name" */ ©_data, NULL, /* no "synchronous_commit" */ &refresh, NULL, NULL, /* no "binary" */ NULL, NULL); /* no "streaming" */ values[Anum_pg_subscription_subpublications - 1] = publicationListToArray(stmt->publication); replaces[Anum_pg_subscription_subpublications - 1] = true; update_tuple = true; /* Refresh if user asked us to. */ if (refresh) { if (!sub->enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("ALTER SUBSCRIPTION with refresh is not allowed for disabled subscriptions"), errhint("Use ALTER SUBSCRIPTION ... SET PUBLICATION ... WITH (refresh = false)."))); PreventInTransactionBlock(isTopLevel, "ALTER SUBSCRIPTION with refresh"); /* Make sure refresh sees the new list of publications. */ sub->publications = stmt->publication; AlterSubscription_refresh(sub, copy_data); } break; } case ALTER_SUBSCRIPTION_REFRESH: { bool copy_data; if (!sub->enabled) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("ALTER SUBSCRIPTION ... REFRESH is not allowed for disabled subscriptions"))); parse_subscription_options(stmt->options, NULL, /* no "connect" */ NULL, NULL, /* no "enabled" */ NULL, /* no "create_slot" */ NULL, NULL, /* no "slot_name" */ ©_data, NULL, /* no "synchronous_commit" */ NULL, /* no "refresh" */ NULL, NULL, /* no "binary" */ NULL, NULL); /* no "streaming" */ PreventInTransactionBlock(isTopLevel, "ALTER SUBSCRIPTION ... REFRESH"); AlterSubscription_refresh(sub, copy_data); break; } default: elog(ERROR, "unrecognized ALTER SUBSCRIPTION kind %d", stmt->kind); } /* Update the catalog if needed. */ if (update_tuple) { tup = heap_modify_tuple(tup, RelationGetDescr(rel), values, nulls, replaces); CatalogTupleUpdate(rel, &tup->t_self, tup); heap_freetuple(tup); } table_close(rel, RowExclusiveLock); ObjectAddressSet(myself, SubscriptionRelationId, subid); InvokeObjectPostAlterHook(SubscriptionRelationId, subid, 0); return myself; } /* * Drop a subscription */ void DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel) { Relation rel; ObjectAddress myself; HeapTuple tup; Oid subid; Datum datum; bool isnull; char *subname; char *conninfo; char *slotname; List *subworkers; ListCell *lc; char originname[NAMEDATALEN]; char *err = NULL; WalReceiverConn *wrconn = NULL; Form_pg_subscription form; List *rstates; /* * Lock pg_subscription with AccessExclusiveLock to ensure that the * launcher doesn't restart new worker during dropping the subscription */ rel = table_open(SubscriptionRelationId, AccessExclusiveLock); tup = SearchSysCache2(SUBSCRIPTIONNAME, MyDatabaseId, CStringGetDatum(stmt->subname)); if (!HeapTupleIsValid(tup)) { table_close(rel, NoLock); if (!stmt->missing_ok) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("subscription \"%s\" does not exist", stmt->subname))); else ereport(NOTICE, (errmsg("subscription \"%s\" does not exist, skipping", stmt->subname))); return; } form = (Form_pg_subscription) GETSTRUCT(tup); subid = form->oid; /* must be owner */ if (!pg_subscription_ownercheck(subid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_SUBSCRIPTION, stmt->subname); /* DROP hook for the subscription being removed */ InvokeObjectDropHook(SubscriptionRelationId, subid, 0); /* * Lock the subscription so nobody else can do anything with it (including * the replication workers). */ LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock); /* Get subname */ datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup, Anum_pg_subscription_subname, &isnull); Assert(!isnull); subname = pstrdup(NameStr(*DatumGetName(datum))); /* Get conninfo */ datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup, Anum_pg_subscription_subconninfo, &isnull); Assert(!isnull); conninfo = TextDatumGetCString(datum); /* Get slotname */ datum = SysCacheGetAttr(SUBSCRIPTIONOID, tup, Anum_pg_subscription_subslotname, &isnull); if (!isnull) slotname = pstrdup(NameStr(*DatumGetName(datum))); else slotname = NULL; /* * Since dropping a replication slot is not transactional, the replication * slot stays dropped even if the transaction rolls back. So we cannot * run DROP SUBSCRIPTION inside a transaction block if dropping the * replication slot. * * XXX The command name should really be something like "DROP SUBSCRIPTION * of a subscription that is associated with a replication slot", but we * don't have the proper facilities for that. */ if (slotname) PreventInTransactionBlock(isTopLevel, "DROP SUBSCRIPTION"); ObjectAddressSet(myself, SubscriptionRelationId, subid); EventTriggerSQLDropAddObject(&myself, true, true); /* Remove the tuple from catalog. */ CatalogTupleDelete(rel, &tup->t_self); ReleaseSysCache(tup); /* * Stop all the subscription workers immediately. * * This is necessary if we are dropping the replication slot, so that the * slot becomes accessible. * * It is also necessary if the subscription is disabled and was disabled * in the same transaction. Then the workers haven't seen the disabling * yet and will still be running, leading to hangs later when we want to * drop the replication origin. If the subscription was disabled before * this transaction, then there shouldn't be any workers left, so this * won't make a difference. * * New workers won't be started because we hold an exclusive lock on the * subscription till the end of the transaction. */ LWLockAcquire(LogicalRepWorkerLock, LW_SHARED); subworkers = logicalrep_workers_find(subid, false); LWLockRelease(LogicalRepWorkerLock); foreach(lc, subworkers) { LogicalRepWorker *w = (LogicalRepWorker *) lfirst(lc); logicalrep_worker_stop(w->subid, w->relid); } list_free(subworkers); /* * Cleanup of tablesync replication origins. * * Any READY-state relations would already have dealt with clean-ups. * * Note that the state can't change because we have already stopped both * the apply and tablesync workers and they can't restart because of * exclusive lock on the subscription. */ rstates = GetSubscriptionNotReadyRelations(subid); foreach(lc, rstates) { SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc); Oid relid = rstate->relid; /* Only cleanup resources of tablesync workers */ if (!OidIsValid(relid)) continue; /* * Drop the tablesync's origin tracking if exists. * * It is possible that the origin is not yet created for tablesync * worker so passing missing_ok = true. This can happen for the states * before SUBREL_STATE_FINISHEDCOPY. */ ReplicationOriginNameForTablesync(subid, relid, originname, sizeof(originname)); replorigin_drop_by_name(originname, true, false); } /* Clean up dependencies */ deleteSharedDependencyRecordsFor(SubscriptionRelationId, subid, 0); /* Remove any associated relation synchronization states. */ RemoveSubscriptionRel(subid, InvalidOid); /* Remove the origin tracking if exists. */ snprintf(originname, sizeof(originname), "pg_%u", subid); replorigin_drop_by_name(originname, true, false); /* * If there is no slot associated with the subscription, we can finish * here. */ if (!slotname && rstates == NIL) { table_close(rel, NoLock); return; } /* * Try to acquire the connection necessary for dropping slots. * * Note: If the slotname is NONE/NULL then we allow the command to finish * and users need to manually cleanup the apply and tablesync worker slots * later. * * This has to be at the end because otherwise if there is an error while * doing the database operations we won't be able to rollback dropped * slot. */ load_file("libpqwalreceiver", false); wrconn = walrcv_connect(conninfo, true, subname, &err); if (wrconn == NULL) { if (!slotname) { /* be tidy */ list_free(rstates); table_close(rel, NoLock); return; } else { ReportSlotConnectionError(rstates, subid, slotname, err); } } PG_TRY(); { foreach(lc, rstates) { SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc); Oid relid = rstate->relid; /* Only cleanup resources of tablesync workers */ if (!OidIsValid(relid)) continue; /* * Drop the tablesync slots associated with removed tables. * * For SYNCDONE/READY states, the tablesync slot is known to have * already been dropped by the tablesync worker. * * For other states, there is no certainty, maybe the slot does * not exist yet. Also, if we fail after removing some of the * slots, next time, it will again try to drop already dropped * slots and fail. For these reasons, we allow missing_ok = true * for the drop. */ if (rstate->state != SUBREL_STATE_SYNCDONE) { char syncslotname[NAMEDATALEN] = {0}; ReplicationSlotNameForTablesync(subid, relid, syncslotname, sizeof(syncslotname)); ReplicationSlotDropAtPubNode(wrconn, syncslotname, true); } } list_free(rstates); /* * If there is a slot associated with the subscription, then drop the * replication slot at the publisher. */ if (slotname) ReplicationSlotDropAtPubNode(wrconn, slotname, false); } PG_FINALLY(); { walrcv_disconnect(wrconn); } PG_END_TRY(); table_close(rel, NoLock); } /* * Drop the replication slot at the publisher node using the replication * connection. * * missing_ok - if true then only issue a LOG message if the slot doesn't * exist. */ void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname, bool missing_ok) { StringInfoData cmd; Assert(wrconn); load_file("libpqwalreceiver", false); initStringInfo(&cmd); appendStringInfo(&cmd, "DROP_REPLICATION_SLOT %s WAIT", quote_identifier(slotname)); PG_TRY(); { WalRcvExecResult *res; res = walrcv_exec(wrconn, cmd.data, 0, NULL); if (res->status == WALRCV_OK_COMMAND) { /* NOTICE. Success. */ ereport(NOTICE, (errmsg("dropped replication slot \"%s\" on publisher", slotname))); } else if (res->status == WALRCV_ERROR && missing_ok && res->sqlstate == ERRCODE_UNDEFINED_OBJECT) { /* LOG. Error, but missing_ok = true. */ ereport(LOG, (errmsg("could not drop the replication slot \"%s\" on publisher", slotname), errdetail("The error was: %s", res->err))); } else { /* ERROR. */ ereport(ERROR, (errmsg("could not drop the replication slot \"%s\" on publisher", slotname), errdetail("The error was: %s", res->err))); } walrcv_clear_result(res); } PG_FINALLY(); { pfree(cmd.data); } PG_END_TRY(); } /* * Internal workhorse for changing a subscription owner */ static void AlterSubscriptionOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId) { Form_pg_subscription form; form = (Form_pg_subscription) GETSTRUCT(tup); if (form->subowner == newOwnerId) return; if (!pg_subscription_ownercheck(form->oid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_SUBSCRIPTION, NameStr(form->subname)); /* New owner must be a superuser */ if (!superuser_arg(newOwnerId)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied to change owner of subscription \"%s\"", NameStr(form->subname)), errhint("The owner of a subscription must be a superuser."))); form->subowner = newOwnerId; CatalogTupleUpdate(rel, &tup->t_self, tup); /* Update owner dependency reference */ changeDependencyOnOwner(SubscriptionRelationId, form->oid, newOwnerId); InvokeObjectPostAlterHook(SubscriptionRelationId, form->oid, 0); } /* * Change subscription owner -- by name */ ObjectAddress AlterSubscriptionOwner(const char *name, Oid newOwnerId) { Oid subid; HeapTuple tup; Relation rel; ObjectAddress address; Form_pg_subscription form; rel = table_open(SubscriptionRelationId, RowExclusiveLock); tup = SearchSysCacheCopy2(SUBSCRIPTIONNAME, MyDatabaseId, CStringGetDatum(name)); if (!HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("subscription \"%s\" does not exist", name))); form = (Form_pg_subscription) GETSTRUCT(tup); subid = form->oid; AlterSubscriptionOwner_internal(rel, tup, newOwnerId); ObjectAddressSet(address, SubscriptionRelationId, subid); heap_freetuple(tup); table_close(rel, RowExclusiveLock); return address; } /* * Change subscription owner -- by OID */ void AlterSubscriptionOwner_oid(Oid subid, Oid newOwnerId) { HeapTuple tup; Relation rel; rel = table_open(SubscriptionRelationId, RowExclusiveLock); tup = SearchSysCacheCopy1(SUBSCRIPTIONOID, ObjectIdGetDatum(subid)); if (!HeapTupleIsValid(tup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("subscription with OID %u does not exist", subid))); AlterSubscriptionOwner_internal(rel, tup, newOwnerId); heap_freetuple(tup); table_close(rel, RowExclusiveLock); } /* * Get the list of tables which belong to specified publications on the * publisher connection. */ static List * fetch_table_list(WalReceiverConn *wrconn, List *publications) { WalRcvExecResult *res; StringInfoData cmd; TupleTableSlot *slot; Oid tableRow[2] = {TEXTOID, TEXTOID}; ListCell *lc; bool first; List *tablelist = NIL; Assert(list_length(publications) > 0); initStringInfo(&cmd); appendStringInfoString(&cmd, "SELECT DISTINCT t.schemaname, t.tablename\n" " FROM pg_catalog.pg_publication_tables t\n" " WHERE t.pubname IN ("); first = true; foreach(lc, publications) { char *pubname = strVal(lfirst(lc)); if (first) first = false; else appendStringInfoString(&cmd, ", "); appendStringInfoString(&cmd, quote_literal_cstr(pubname)); } appendStringInfoChar(&cmd, ')'); res = walrcv_exec(wrconn, cmd.data, 2, tableRow); pfree(cmd.data); if (res->status != WALRCV_OK_TUPLES) ereport(ERROR, (errmsg("could not receive list of replicated tables from the publisher: %s", res->err))); /* Process tables. */ slot = MakeSingleTupleTableSlot(res->tupledesc, &TTSOpsMinimalTuple); while (tuplestore_gettupleslot(res->tuplestore, true, false, slot)) { char *nspname; char *relname; bool isnull; RangeVar *rv; nspname = TextDatumGetCString(slot_getattr(slot, 1, &isnull)); Assert(!isnull); relname = TextDatumGetCString(slot_getattr(slot, 2, &isnull)); Assert(!isnull); rv = makeRangeVar(nspname, relname, -1); tablelist = lappend(tablelist, rv); ExecClearTuple(slot); } ExecDropSingleTupleTableSlot(slot); walrcv_clear_result(res); return tablelist; } /* * This is to report the connection failure while dropping replication slots. * Here, we report the WARNING for all tablesync slots so that user can drop * them manually, if required. */ static void ReportSlotConnectionError(List *rstates, Oid subid, char *slotname, char *err) { ListCell *lc; foreach(lc, rstates) { SubscriptionRelState *rstate = (SubscriptionRelState *) lfirst(lc); Oid relid = rstate->relid; /* Only cleanup resources of tablesync workers */ if (!OidIsValid(relid)) continue; /* * Caller needs to ensure that relstate doesn't change underneath us. * See DropSubscription where we get the relstates. */ if (rstate->state != SUBREL_STATE_SYNCDONE) { char syncslotname[NAMEDATALEN] = {0}; ReplicationSlotNameForTablesync(subid, relid, syncslotname, sizeof(syncslotname)); elog(WARNING, "could not drop tablesync replication slot \"%s\"", syncslotname); } } ereport(ERROR, (errmsg("could not connect to publisher when attempting to " "drop the replication slot \"%s\"", slotname), errdetail("The error was: %s", err), /* translator: %s is an SQL ALTER command */ errhint("Use %s to disassociate the subscription from the slot.", "ALTER SUBSCRIPTION ... SET (slot_name = NONE)"))); }