pgindent run for 9.4

[postgresql] / src / backend / utils / cache / inval.c

/*-------------------------------------------------------------------------
 *
 * inval.c
 *        POSTGRES cache invalidation dispatcher code.
 *
 *      This is subtle stuff, so pay attention:
 *
 *      When a tuple is updated or deleted, our standard time qualification rules
 *      consider that it is *still valid* so long as we are in the same command,
 *      ie, until the next CommandCounterIncrement() or transaction commit.
 *      (See utils/time/tqual.c, and note that system catalogs are generally
 *      scanned under the most current snapshot available, rather than the
 *      transaction snapshot.)  At the command boundary, the old tuple stops
 *      being valid and the new version, if any, becomes valid.  Therefore,
 *      we cannot simply flush a tuple from the system caches during heap_update()
 *      or heap_delete().  The tuple is still good at that point; what's more,
 *      even if we did flush it, it might be reloaded into the caches by a later
 *      request in the same command.  So the correct behavior is to keep a list
 *      of outdated (updated/deleted) tuples and then do the required cache
 *      flushes at the next command boundary.  We must also keep track of
 *      inserted tuples so that we can flush "negative" cache entries that match
 *      the new tuples; again, that mustn't happen until end of command.
 *
 *      Once we have finished the command, we still need to remember inserted
 *      tuples (including new versions of updated tuples), so that we can flush
 *      them from the caches if we abort the transaction.  Similarly, we'd better
 *      be able to flush "negative" cache entries that may have been loaded in
 *      place of deleted tuples, so we still need the deleted ones too.
 *
 *      If we successfully complete the transaction, we have to broadcast all
 *      these invalidation events to other backends (via the SI message queue)
 *      so that they can flush obsolete entries from their caches.  Note we have
 *      to record the transaction commit before sending SI messages, otherwise
 *      the other backends won't see our updated tuples as good.
 *
 *      When a subtransaction aborts, we can process and discard any events
 *      it has queued.  When a subtransaction commits, we just add its events
 *      to the pending lists of the parent transaction.
 *
 *      In short, we need to remember until xact end every insert or delete
 *      of a tuple that might be in the system caches.  Updates are treated as
 *      two events, delete + insert, for simplicity.  (If the update doesn't
 *      change the tuple hash value, catcache.c optimizes this into one event.)
 *
 *      We do not need to register EVERY tuple operation in this way, just those
 *      on tuples in relations that have associated catcaches.  We do, however,
 *      have to register every operation on every tuple that *could* be in a
 *      catcache, whether or not it currently is in our cache.  Also, if the
 *      tuple is in a relation that has multiple catcaches, we need to register
 *      an invalidation message for each such catcache.  catcache.c's
 *      PrepareToInvalidateCacheTuple() routine provides the knowledge of which
 *      catcaches may need invalidation for a given tuple.
 *
 *      Also, whenever we see an operation on a pg_class or pg_attribute tuple,
 *      we register a relcache flush operation for the relation described by that
 *      tuple.
 *
 *      We keep the relcache flush requests in lists separate from the catcache
 *      tuple flush requests.  This allows us to issue all the pending catcache
 *      flushes before we issue relcache flushes, which saves us from loading
 *      a catcache tuple during relcache load only to flush it again right away.
 *      Also, we avoid queuing multiple relcache flush requests for the same
 *      relation, since a relcache flush is relatively expensive to do.
 *      (XXX is it worth testing likewise for duplicate catcache flush entries?
 *      Probably not.)
 *
 *      If a relcache flush is issued for a system relation that we preload
 *      from the relcache init file, we must also delete the init file so that
 *      it will be rebuilt during the next backend restart.  The actual work of
 *      manipulating the init file is in relcache.c, but we keep track of the
 *      need for it here.
 *
 *      The request lists proper are kept in CurTransactionContext of their
 *      creating (sub)transaction, since they can be forgotten on abort of that
 *      transaction but must be kept till top-level commit otherwise.  For
 *      simplicity we keep the controlling list-of-lists in TopTransactionContext.
 *
 *      Currently, inval messages are sent without regard for the possibility
 *      that the object described by the catalog tuple might be a session-local
 *      object such as a temporary table.  This is because (1) this code has
 *      no practical way to tell the difference, and (2) it is not certain that
 *      other backends don't have catalog cache or even relcache entries for
 *      such tables, anyway; there is nothing that prevents that.  It might be
 *      worth trying to avoid sending such inval traffic in the future, if those
 *      problems can be overcome cheaply.
 *
 *
 * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *        src/backend/utils/cache/inval.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/htup_details.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "miscadmin.h"
#include "storage/sinval.h"
#include "storage/smgr.h"
#include "utils/catcache.h"
#include "utils/inval.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/relmapper.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"


/*
 * To minimize palloc traffic, we keep pending requests in successively-
 * larger chunks (a slightly more sophisticated version of an expansible
 * array).  All request types can be stored as SharedInvalidationMessage
 * records.  The ordering of requests within a list is never significant.
 */
typedef struct InvalidationChunk
{
        struct InvalidationChunk *next;         /* list link */
        int                     nitems;                 /* # items currently stored in chunk */
        int                     maxitems;               /* size of allocated array in this chunk */
        SharedInvalidationMessage msgs[1];      /* VARIABLE LENGTH ARRAY */
} InvalidationChunk;                    /* VARIABLE LENGTH STRUCTURE */

typedef struct InvalidationListHeader
{
        InvalidationChunk *cclist;      /* list of chunks holding catcache msgs */
        InvalidationChunk *rclist;      /* list of chunks holding relcache msgs */
} InvalidationListHeader;

/*----------------
 * Invalidation info is divided into two lists:
 *      1) events so far in current command, not yet reflected to caches.
 *      2) events in previous commands of current transaction; these have
 *         been reflected to local caches, and must be either broadcast to
 *         other backends or rolled back from local cache when we commit
 *         or abort the transaction.
 * Actually, we need two such lists for each level of nested transaction,
 * so that we can discard events from an aborted subtransaction.  When
 * a subtransaction commits, we append its lists to the parent's lists.
 *
 * The relcache-file-invalidated flag can just be a simple boolean,
 * since we only act on it at transaction commit; we don't care which
 * command of the transaction set it.
 *----------------
 */

typedef struct TransInvalidationInfo
{
        /* Back link to parent transaction's info */
        struct TransInvalidationInfo *parent;

        /* Subtransaction nesting depth */
        int                     my_level;

        /* head of current-command event list */
        InvalidationListHeader CurrentCmdInvalidMsgs;

        /* head of previous-commands event list */
        InvalidationListHeader PriorCmdInvalidMsgs;

        /* init file must be invalidated? */
        bool            RelcacheInitFileInval;
} TransInvalidationInfo;

static TransInvalidationInfo *transInvalInfo = NULL;

static SharedInvalidationMessage *SharedInvalidMessagesArray;
static int      numSharedInvalidMessagesArray;
static int      maxSharedInvalidMessagesArray;


/*
 * Dynamically-registered callback functions.  Current implementation
 * assumes there won't be very many of these at once; could improve if needed.
 */

#define MAX_SYSCACHE_CALLBACKS 32
#define MAX_RELCACHE_CALLBACKS 10

static struct SYSCACHECALLBACK
{
        int16           id;                             /* cache number */
        SyscacheCallbackFunction function;
        Datum           arg;
}       syscache_callback_list[MAX_SYSCACHE_CALLBACKS];

static int      syscache_callback_count = 0;

static struct RELCACHECALLBACK
{
        RelcacheCallbackFunction function;
        Datum           arg;
}       relcache_callback_list[MAX_RELCACHE_CALLBACKS];

static int      relcache_callback_count = 0;

/* ----------------------------------------------------------------
 *                              Invalidation list support functions
 *
 * These three routines encapsulate processing of the "chunked"
 * representation of what is logically just a list of messages.
 * ----------------------------------------------------------------
 */

/*
 * AddInvalidationMessage
 *              Add an invalidation message to a list (of chunks).
 *
 * Note that we do not pay any great attention to maintaining the original
 * ordering of the messages.
 */
static void
AddInvalidationMessage(InvalidationChunk **listHdr,
                                           SharedInvalidationMessage *msg)
{
        InvalidationChunk *chunk = *listHdr;

        if (chunk == NULL)
        {
                /* First time through; create initial chunk */
#define FIRSTCHUNKSIZE 32
                chunk = (InvalidationChunk *)
                        MemoryContextAlloc(CurTransactionContext,
                                                           sizeof(InvalidationChunk) +
                                        (FIRSTCHUNKSIZE - 1) *sizeof(SharedInvalidationMessage));
                chunk->nitems = 0;
                chunk->maxitems = FIRSTCHUNKSIZE;
                chunk->next = *listHdr;
                *listHdr = chunk;
        }
        else if (chunk->nitems >= chunk->maxitems)
        {
                /* Need another chunk; double size of last chunk */
                int                     chunksize = 2 * chunk->maxitems;

                chunk = (InvalidationChunk *)
                        MemoryContextAlloc(CurTransactionContext,
                                                           sizeof(InvalidationChunk) +
                                                 (chunksize - 1) *sizeof(SharedInvalidationMessage));
                chunk->nitems = 0;
                chunk->maxitems = chunksize;
                chunk->next = *listHdr;
                *listHdr = chunk;
        }
        /* Okay, add message to current chunk */
        chunk->msgs[chunk->nitems] = *msg;
        chunk->nitems++;
}

/*
 * Append one list of invalidation message chunks to another, resetting
 * the source chunk-list pointer to NULL.
 */
static void
AppendInvalidationMessageList(InvalidationChunk **destHdr,
                                                          InvalidationChunk **srcHdr)
{
        InvalidationChunk *chunk = *srcHdr;

        if (chunk == NULL)
                return;                                 /* nothing to do */

        while (chunk->next != NULL)
                chunk = chunk->next;

        chunk->next = *destHdr;

        *destHdr = *srcHdr;

        *srcHdr = NULL;
}

/*
 * Process a list of invalidation messages.
 *
 * This is a macro that executes the given code fragment for each message in
 * a message chunk list.  The fragment should refer to the message as *msg.
 */
#define ProcessMessageList(listHdr, codeFragment) \
        do { \
                InvalidationChunk *_chunk; \
                for (_chunk = (listHdr); _chunk != NULL; _chunk = _chunk->next) \
                { \
                        int             _cindex; \
                        for (_cindex = 0; _cindex < _chunk->nitems; _cindex++) \
                        { \
                                SharedInvalidationMessage *msg = &_chunk->msgs[_cindex]; \
                                codeFragment; \
                        } \
                } \
        } while (0)

/*
 * Process a list of invalidation messages group-wise.
 *
 * As above, but the code fragment can handle an array of messages.
 * The fragment should refer to the messages as msgs[], with n entries.
 */
#define ProcessMessageListMulti(listHdr, codeFragment) \
        do { \
                InvalidationChunk *_chunk; \
                for (_chunk = (listHdr); _chunk != NULL; _chunk = _chunk->next) \
                { \
                        SharedInvalidationMessage *msgs = _chunk->msgs; \
                        int             n = _chunk->nitems; \
                        codeFragment; \
                } \
        } while (0)


/* ----------------------------------------------------------------
 *                              Invalidation set support functions
 *
 * These routines understand about the division of a logical invalidation
 * list into separate physical lists for catcache and relcache entries.
 * ----------------------------------------------------------------
 */

/*
 * Add a catcache inval entry
 */
static void
AddCatcacheInvalidationMessage(InvalidationListHeader *hdr,
                                                           int id, uint32 hashValue, Oid dbId)
{
        SharedInvalidationMessage msg;

        Assert(id < CHAR_MAX);
        msg.cc.id = (int8) id;
        msg.cc.dbId = dbId;
        msg.cc.hashValue = hashValue;
        AddInvalidationMessage(&hdr->cclist, &msg);
}

/*
 * Add a whole-catalog inval entry
 */
static void
AddCatalogInvalidationMessage(InvalidationListHeader *hdr,
                                                          Oid dbId, Oid catId)
{
        SharedInvalidationMessage msg;

        msg.cat.id = SHAREDINVALCATALOG_ID;
        msg.cat.dbId = dbId;
        msg.cat.catId = catId;
        AddInvalidationMessage(&hdr->cclist, &msg);
}

/*
 * Add a relcache inval entry
 */
static void
AddRelcacheInvalidationMessage(InvalidationListHeader *hdr,
                                                           Oid dbId, Oid relId)
{
        SharedInvalidationMessage msg;

        /* Don't add a duplicate item */
        /* We assume dbId need not be checked because it will never change */
        ProcessMessageList(hdr->rclist,
                                           if (msg->rc.id == SHAREDINVALRELCACHE_ID &&
                                                   msg->rc.relId == relId)
                                           return);

        /* OK, add the item */
        msg.rc.id = SHAREDINVALRELCACHE_ID;
        msg.rc.dbId = dbId;
        msg.rc.relId = relId;
        AddInvalidationMessage(&hdr->rclist, &msg);
}

/*
 * Add a snapshot inval entry
 */
static void
AddSnapshotInvalidationMessage(InvalidationListHeader *hdr,
                                                           Oid dbId, Oid relId)
{
        SharedInvalidationMessage msg;

        /* Don't add a duplicate item */
        /* We assume dbId need not be checked because it will never change */
        ProcessMessageList(hdr->rclist,
                                           if (msg->sn.id == SHAREDINVALSNAPSHOT_ID &&
                                                   msg->sn.relId == relId)
                                           return);

        /* OK, add the item */
        msg.sn.id = SHAREDINVALSNAPSHOT_ID;
        msg.sn.dbId = dbId;
        msg.sn.relId = relId;
        AddInvalidationMessage(&hdr->rclist, &msg);
}

/*
 * Append one list of invalidation messages to another, resetting
 * the source list to empty.
 */
static void
AppendInvalidationMessages(InvalidationListHeader *dest,
                                                   InvalidationListHeader *src)
{
        AppendInvalidationMessageList(&dest->cclist, &src->cclist);
        AppendInvalidationMessageList(&dest->rclist, &src->rclist);
}

/*
 * Execute the given function for all the messages in an invalidation list.
 * The list is not altered.
 *
 * catcache entries are processed first, for reasons mentioned above.
 */
static void
ProcessInvalidationMessages(InvalidationListHeader *hdr,
                                                        void (*func) (SharedInvalidationMessage *msg))
{
        ProcessMessageList(hdr->cclist, func(msg));
        ProcessMessageList(hdr->rclist, func(msg));
}

/*
 * As above, but the function is able to process an array of messages
 * rather than just one at a time.
 */
static void
ProcessInvalidationMessagesMulti(InvalidationListHeader *hdr,
                                 void (*func) (const SharedInvalidationMessage *msgs, int n))
{
        ProcessMessageListMulti(hdr->cclist, func(msgs, n));
        ProcessMessageListMulti(hdr->rclist, func(msgs, n));
}

/* ----------------------------------------------------------------
 *                                        private support functions
 * ----------------------------------------------------------------
 */

/*
 * RegisterCatcacheInvalidation
 *
 * Register an invalidation event for a catcache tuple entry.
 */
static void
RegisterCatcacheInvalidation(int cacheId,
                                                         uint32 hashValue,
                                                         Oid dbId)
{
        AddCatcacheInvalidationMessage(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                   cacheId, hashValue, dbId);
}

/*
 * RegisterCatalogInvalidation
 *
 * Register an invalidation event for all catcache entries from a catalog.
 */
static void
RegisterCatalogInvalidation(Oid dbId, Oid catId)
{
        AddCatalogInvalidationMessage(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                  dbId, catId);
}

/*
 * RegisterRelcacheInvalidation
 *
 * As above, but register a relcache invalidation event.
 */
static void
RegisterRelcacheInvalidation(Oid dbId, Oid relId)
{
        AddRelcacheInvalidationMessage(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                   dbId, relId);

        /*
         * Most of the time, relcache invalidation is associated with system
         * catalog updates, but there are a few cases where it isn't.  Quick hack
         * to ensure that the next CommandCounterIncrement() will think that we
         * need to do CommandEndInvalidationMessages().
         */
        (void) GetCurrentCommandId(true);

        /*
         * If the relation being invalidated is one of those cached in the
         * relcache init file, mark that we need to zap that file at commit.
         */
        if (RelationIdIsInInitFile(relId))
                transInvalInfo->RelcacheInitFileInval = true;
}

/*
 * RegisterSnapshotInvalidation
 *
 * Register a invalidation event for MVCC scans against a given catalog.
 * Only needed for catalogs that don't have catcaches.
 */
static void
RegisterSnapshotInvalidation(Oid dbId, Oid relId)
{
        AddSnapshotInvalidationMessage(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                   dbId, relId);
}

/*
 * LocalExecuteInvalidationMessage
 *
 * Process a single invalidation message (which could be of any type).
 * Only the local caches are flushed; this does not transmit the message
 * to other backends.
 */
void
LocalExecuteInvalidationMessage(SharedInvalidationMessage *msg)
{
        if (msg->id >= 0)
        {
                if (msg->cc.dbId == MyDatabaseId || msg->cc.dbId == InvalidOid)
                {
                        InvalidateCatalogSnapshot();

                        CatalogCacheIdInvalidate(msg->cc.id, msg->cc.hashValue);

                        CallSyscacheCallbacks(msg->cc.id, msg->cc.hashValue);
                }
        }
        else if (msg->id == SHAREDINVALCATALOG_ID)
        {
                if (msg->cat.dbId == MyDatabaseId || msg->cat.dbId == InvalidOid)
                {
                        InvalidateCatalogSnapshot();

                        CatalogCacheFlushCatalog(msg->cat.catId);

                        /* CatalogCacheFlushCatalog calls CallSyscacheCallbacks as needed */
                }
        }
        else if (msg->id == SHAREDINVALRELCACHE_ID)
        {
                if (msg->rc.dbId == MyDatabaseId || msg->rc.dbId == InvalidOid)
                {
                        int                     i;

                        RelationCacheInvalidateEntry(msg->rc.relId);

                        for (i = 0; i < relcache_callback_count; i++)
                        {
                                struct RELCACHECALLBACK *ccitem = relcache_callback_list + i;

                                (*ccitem->function) (ccitem->arg, msg->rc.relId);
                        }
                }
        }
        else if (msg->id == SHAREDINVALSMGR_ID)
        {
                /*
                 * We could have smgr entries for relations of other databases, so no
                 * short-circuit test is possible here.
                 */
                RelFileNodeBackend rnode;

                rnode.node = msg->sm.rnode;
                rnode.backend = (msg->sm.backend_hi << 16) | (int) msg->sm.backend_lo;
                smgrclosenode(rnode);
        }
        else if (msg->id == SHAREDINVALRELMAP_ID)
        {
                /* We only care about our own database and shared catalogs */
                if (msg->rm.dbId == InvalidOid)
                        RelationMapInvalidate(true);
                else if (msg->rm.dbId == MyDatabaseId)
                        RelationMapInvalidate(false);
        }
        else if (msg->id == SHAREDINVALSNAPSHOT_ID)
        {
                /* We only care about our own database and shared catalogs */
                if (msg->rm.dbId == InvalidOid)
                        InvalidateCatalogSnapshot();
                else if (msg->rm.dbId == MyDatabaseId)
                        InvalidateCatalogSnapshot();
        }
        else
                elog(FATAL, "unrecognized SI message ID: %d", msg->id);
}

/*
 *              InvalidateSystemCaches
 *
 *              This blows away all tuples in the system catalog caches and
 *              all the cached relation descriptors and smgr cache entries.
 *              Relation descriptors that have positive refcounts are then rebuilt.
 *
 *              We call this when we see a shared-inval-queue overflow signal,
 *              since that tells us we've lost some shared-inval messages and hence
 *              don't know what needs to be invalidated.
 */
void
InvalidateSystemCaches(void)
{
        int                     i;

        InvalidateCatalogSnapshot();
        ResetCatalogCaches();
        RelationCacheInvalidate();      /* gets smgr and relmap too */

        for (i = 0; i < syscache_callback_count; i++)
        {
                struct SYSCACHECALLBACK *ccitem = syscache_callback_list + i;

                (*ccitem->function) (ccitem->arg, ccitem->id, 0);
        }

        for (i = 0; i < relcache_callback_count; i++)
        {
                struct RELCACHECALLBACK *ccitem = relcache_callback_list + i;

                (*ccitem->function) (ccitem->arg, InvalidOid);
        }
}


/* ----------------------------------------------------------------
 *                                        public functions
 * ----------------------------------------------------------------
 */

/*
 * AcceptInvalidationMessages
 *              Read and process invalidation messages from the shared invalidation
 *              message queue.
 *
 * Note:
 *              This should be called as the first step in processing a transaction.
 */
void
AcceptInvalidationMessages(void)
{
        ReceiveSharedInvalidMessages(LocalExecuteInvalidationMessage,
                                                                 InvalidateSystemCaches);

        /*
         * Test code to force cache flushes anytime a flush could happen.
         *
         * If used with CLOBBER_FREED_MEMORY, CLOBBER_CACHE_ALWAYS provides a
         * fairly thorough test that the system contains no cache-flush hazards.
         * However, it also makes the system unbelievably slow --- the regression
         * tests take about 100 times longer than normal.
         *
         * If you're a glutton for punishment, try CLOBBER_CACHE_RECURSIVELY. This
         * slows things by at least a factor of 10000, so I wouldn't suggest
         * trying to run the entire regression tests that way.  It's useful to try
         * a few simple tests, to make sure that cache reload isn't subject to
         * internal cache-flush hazards, but after you've done a few thousand
         * recursive reloads it's unlikely you'll learn more.
         */
#if defined(CLOBBER_CACHE_ALWAYS)
        {
                static bool in_recursion = false;

                if (!in_recursion)
                {
                        in_recursion = true;
                        InvalidateSystemCaches();
                        in_recursion = false;
                }
        }
#elif defined(CLOBBER_CACHE_RECURSIVELY)
        InvalidateSystemCaches();
#endif
}

/*
 * AtStart_Inval
 *              Initialize inval lists at start of a main transaction.
 */
void
AtStart_Inval(void)
{
        Assert(transInvalInfo == NULL);
        transInvalInfo = (TransInvalidationInfo *)
                MemoryContextAllocZero(TopTransactionContext,
                                                           sizeof(TransInvalidationInfo));
        transInvalInfo->my_level = GetCurrentTransactionNestLevel();
        SharedInvalidMessagesArray = NULL;
        numSharedInvalidMessagesArray = 0;
}

/*
 * PostPrepare_Inval
 *              Clean up after successful PREPARE.
 *
 * Here, we want to act as though the transaction aborted, so that we will
 * undo any syscache changes it made, thereby bringing us into sync with the
 * outside world, which doesn't believe the transaction committed yet.
 *
 * If the prepared transaction is later aborted, there is nothing more to
 * do; if it commits, we will receive the consequent inval messages just
 * like everyone else.
 */
void
PostPrepare_Inval(void)
{
        AtEOXact_Inval(false);
}

/*
 * AtSubStart_Inval
 *              Initialize inval lists at start of a subtransaction.
 */
void
AtSubStart_Inval(void)
{
        TransInvalidationInfo *myInfo;

        Assert(transInvalInfo != NULL);
        myInfo = (TransInvalidationInfo *)
                MemoryContextAllocZero(TopTransactionContext,
                                                           sizeof(TransInvalidationInfo));
        myInfo->parent = transInvalInfo;
        myInfo->my_level = GetCurrentTransactionNestLevel();
        transInvalInfo = myInfo;
}

/*
 * Collect invalidation messages into SharedInvalidMessagesArray array.
 */
static void
MakeSharedInvalidMessagesArray(const SharedInvalidationMessage *msgs, int n)
{
        /*
         * Initialise array first time through in each commit
         */
        if (SharedInvalidMessagesArray == NULL)
        {
                maxSharedInvalidMessagesArray = FIRSTCHUNKSIZE;
                numSharedInvalidMessagesArray = 0;

                /*
                 * Although this is being palloc'd we don't actually free it directly.
                 * We're so close to EOXact that we now we're going to lose it anyhow.
                 */
                SharedInvalidMessagesArray = palloc(maxSharedInvalidMessagesArray
                                                                                * sizeof(SharedInvalidationMessage));
        }

        if ((numSharedInvalidMessagesArray + n) > maxSharedInvalidMessagesArray)
        {
                while ((numSharedInvalidMessagesArray + n) > maxSharedInvalidMessagesArray)
                        maxSharedInvalidMessagesArray *= 2;

                SharedInvalidMessagesArray = repalloc(SharedInvalidMessagesArray,
                                                                                          maxSharedInvalidMessagesArray
                                                                                * sizeof(SharedInvalidationMessage));
        }

        /*
         * Append the next chunk onto the array
         */
        memcpy(SharedInvalidMessagesArray + numSharedInvalidMessagesArray,
                   msgs, n * sizeof(SharedInvalidationMessage));
        numSharedInvalidMessagesArray += n;
}

/*
 * xactGetCommittedInvalidationMessages() is executed by
 * RecordTransactionCommit() to add invalidation messages onto the
 * commit record. This applies only to commit message types, never to
 * abort records. Must always run before AtEOXact_Inval(), since that
 * removes the data we need to see.
 *
 * Remember that this runs before we have officially committed, so we
 * must not do anything here to change what might occur *if* we should
 * fail between here and the actual commit.
 *
 * see also xact_redo_commit() and xact_desc_commit()
 */
int
xactGetCommittedInvalidationMessages(SharedInvalidationMessage **msgs,
                                                                         bool *RelcacheInitFileInval)
{
        MemoryContext oldcontext;

        /* Must be at top of stack */
        Assert(transInvalInfo != NULL && transInvalInfo->parent == NULL);

        /*
         * Relcache init file invalidation requires processing both before and
         * after we send the SI messages.  However, we need not do anything unless
         * we committed.
         */
        *RelcacheInitFileInval = transInvalInfo->RelcacheInitFileInval;

        /*
         * Walk through TransInvalidationInfo to collect all the messages into a
         * single contiguous array of invalidation messages. It must be contiguous
         * so we can copy directly into WAL message. Maintain the order that they
         * would be processed in by AtEOXact_Inval(), to ensure emulated behaviour
         * in redo is as similar as possible to original. We want the same bugs,
         * if any, not new ones.
         */
        oldcontext = MemoryContextSwitchTo(CurTransactionContext);

        ProcessInvalidationMessagesMulti(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                         MakeSharedInvalidMessagesArray);
        ProcessInvalidationMessagesMulti(&transInvalInfo->PriorCmdInvalidMsgs,
                                                                         MakeSharedInvalidMessagesArray);
        MemoryContextSwitchTo(oldcontext);

        Assert(!(numSharedInvalidMessagesArray > 0 &&
                         SharedInvalidMessagesArray == NULL));

        *msgs = SharedInvalidMessagesArray;

        return numSharedInvalidMessagesArray;
}

/*
 * ProcessCommittedInvalidationMessages is executed by xact_redo_commit()
 * to process invalidation messages added to commit records.
 *
 * Relcache init file invalidation requires processing both
 * before and after we send the SI messages. See AtEOXact_Inval()
 */
void
ProcessCommittedInvalidationMessages(SharedInvalidationMessage *msgs,
                                                                         int nmsgs, bool RelcacheInitFileInval,
                                                                         Oid dbid, Oid tsid)
{
        if (nmsgs <= 0)
                return;

        elog(trace_recovery(DEBUG4), "replaying commit with %d messages%s", nmsgs,
                 (RelcacheInitFileInval ? " and relcache file invalidation" : ""));

        if (RelcacheInitFileInval)
        {
                /*
                 * RelationCacheInitFilePreInvalidate requires DatabasePath to be set,
                 * but we should not use SetDatabasePath during recovery, since it is
                 * intended to be used only once by normal backends.  Hence, a quick
                 * hack: set DatabasePath directly then unset after use.
                 */
                DatabasePath = GetDatabasePath(dbid, tsid);
                elog(trace_recovery(DEBUG4), "removing relcache init file in \"%s\"",
                         DatabasePath);
                RelationCacheInitFilePreInvalidate();
                pfree(DatabasePath);
                DatabasePath = NULL;
        }

        SendSharedInvalidMessages(msgs, nmsgs);

        if (RelcacheInitFileInval)
                RelationCacheInitFilePostInvalidate();
}

/*
 * AtEOXact_Inval
 *              Process queued-up invalidation messages at end of main transaction.
 *
 * If isCommit, we must send out the messages in our PriorCmdInvalidMsgs list
 * to the shared invalidation message queue.  Note that these will be read
 * not only by other backends, but also by our own backend at the next
 * transaction start (via AcceptInvalidationMessages).  This means that
 * we can skip immediate local processing of anything that's still in
 * CurrentCmdInvalidMsgs, and just send that list out too.
 *
 * If not isCommit, we are aborting, and must locally process the messages
 * in PriorCmdInvalidMsgs.  No messages need be sent to other backends,
 * since they'll not have seen our changed tuples anyway.  We can forget
 * about CurrentCmdInvalidMsgs too, since those changes haven't touched
 * the caches yet.
 *
 * In any case, reset the various lists to empty.  We need not physically
 * free memory here, since TopTransactionContext is about to be emptied
 * anyway.
 *
 * Note:
 *              This should be called as the last step in processing a transaction.
 */
void
AtEOXact_Inval(bool isCommit)
{
        if (isCommit)
        {
                /* Must be at top of stack */
                Assert(transInvalInfo != NULL && transInvalInfo->parent == NULL);

                /*
                 * Relcache init file invalidation requires processing both before and
                 * after we send the SI messages.  However, we need not do anything
                 * unless we committed.
                 */
                if (transInvalInfo->RelcacheInitFileInval)
                        RelationCacheInitFilePreInvalidate();

                AppendInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
                                                                   &transInvalInfo->CurrentCmdInvalidMsgs);

                ProcessInvalidationMessagesMulti(&transInvalInfo->PriorCmdInvalidMsgs,
                                                                                 SendSharedInvalidMessages);

                if (transInvalInfo->RelcacheInitFileInval)
                        RelationCacheInitFilePostInvalidate();
        }
        else if (transInvalInfo != NULL)
        {
                /* Must be at top of stack */
                Assert(transInvalInfo->parent == NULL);

                ProcessInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
                                                                        LocalExecuteInvalidationMessage);
        }

        /* Need not free anything explicitly */
        transInvalInfo = NULL;
}

/*
 * AtEOSubXact_Inval
 *              Process queued-up invalidation messages at end of subtransaction.
 *
 * If isCommit, process CurrentCmdInvalidMsgs if any (there probably aren't),
 * and then attach both CurrentCmdInvalidMsgs and PriorCmdInvalidMsgs to the
 * parent's PriorCmdInvalidMsgs list.
 *
 * If not isCommit, we are aborting, and must locally process the messages
 * in PriorCmdInvalidMsgs.  No messages need be sent to other backends.
 * We can forget about CurrentCmdInvalidMsgs too, since those changes haven't
 * touched the caches yet.
 *
 * In any case, pop the transaction stack.  We need not physically free memory
 * here, since CurTransactionContext is about to be emptied anyway
 * (if aborting).  Beware of the possibility of aborting the same nesting
 * level twice, though.
 */
void
AtEOSubXact_Inval(bool isCommit)
{
        int                     my_level = GetCurrentTransactionNestLevel();
        TransInvalidationInfo *myInfo = transInvalInfo;

        if (isCommit)
        {
                /* Must be at non-top of stack */
                Assert(myInfo != NULL && myInfo->parent != NULL);
                Assert(myInfo->my_level == my_level);

                /* If CurrentCmdInvalidMsgs still has anything, fix it */
                CommandEndInvalidationMessages();

                /* Pass up my inval messages to parent */
                AppendInvalidationMessages(&myInfo->parent->PriorCmdInvalidMsgs,
                                                                   &myInfo->PriorCmdInvalidMsgs);

                /* Pending relcache inval becomes parent's problem too */
                if (myInfo->RelcacheInitFileInval)
                        myInfo->parent->RelcacheInitFileInval = true;

                /* Pop the transaction state stack */
                transInvalInfo = myInfo->parent;

                /* Need not free anything else explicitly */
                pfree(myInfo);
        }
        else if (myInfo != NULL && myInfo->my_level == my_level)
        {
                /* Must be at non-top of stack */
                Assert(myInfo->parent != NULL);

                ProcessInvalidationMessages(&myInfo->PriorCmdInvalidMsgs,
                                                                        LocalExecuteInvalidationMessage);

                /* Pop the transaction state stack */
                transInvalInfo = myInfo->parent;

                /* Need not free anything else explicitly */
                pfree(myInfo);
        }
}

/*
 * CommandEndInvalidationMessages
 *              Process queued-up invalidation messages at end of one command
 *              in a transaction.
 *
 * Here, we send no messages to the shared queue, since we don't know yet if
 * we will commit.  We do need to locally process the CurrentCmdInvalidMsgs
 * list, so as to flush our caches of any entries we have outdated in the
 * current command.  We then move the current-cmd list over to become part
 * of the prior-cmds list.
 *
 * Note:
 *              This should be called during CommandCounterIncrement(),
 *              after we have advanced the command ID.
 */
void
CommandEndInvalidationMessages(void)
{
        /*
         * You might think this shouldn't be called outside any transaction, but
         * bootstrap does it, and also ABORT issued when not in a transaction. So
         * just quietly return if no state to work on.
         */
        if (transInvalInfo == NULL)
                return;

        ProcessInvalidationMessages(&transInvalInfo->CurrentCmdInvalidMsgs,
                                                                LocalExecuteInvalidationMessage);
        AppendInvalidationMessages(&transInvalInfo->PriorCmdInvalidMsgs,
                                                           &transInvalInfo->CurrentCmdInvalidMsgs);
}


/*
 * CacheInvalidateHeapTuple
 *              Register the given tuple for invalidation at end of command
 *              (ie, current command is creating or outdating this tuple).
 *              Also, detect whether a relcache invalidation is implied.
 *
 * For an insert or delete, tuple is the target tuple and newtuple is NULL.
 * For an update, we are called just once, with tuple being the old tuple
 * version and newtuple the new version.  This allows avoidance of duplicate
 * effort during an update.
 */
void
CacheInvalidateHeapTuple(Relation relation,
                                                 HeapTuple tuple,
                                                 HeapTuple newtuple)
{
        Oid                     tupleRelId;
        Oid                     databaseId;
        Oid                     relationId;

        /* Do nothing during bootstrap */
        if (IsBootstrapProcessingMode())
                return;

        /*
         * We only need to worry about invalidation for tuples that are in system
         * catalogs; user-relation tuples are never in catcaches and can't affect
         * the relcache either.
         */
        if (!IsCatalogRelation(relation))
                return;

        /*
         * IsCatalogRelation() will return true for TOAST tables of system
         * catalogs, but we don't care about those, either.
         */
        if (IsToastRelation(relation))
                return;

        /*
         * First let the catcache do its thing
         */
        tupleRelId = RelationGetRelid(relation);
        if (RelationInvalidatesSnapshotsOnly(tupleRelId))
        {
                databaseId = IsSharedRelation(tupleRelId) ? InvalidOid : MyDatabaseId;
                RegisterSnapshotInvalidation(databaseId, tupleRelId);
        }
        else
                PrepareToInvalidateCacheTuple(relation, tuple, newtuple,
                                                                          RegisterCatcacheInvalidation);

        /*
         * Now, is this tuple one of the primary definers of a relcache entry?
         *
         * Note we ignore newtuple here; we assume an update cannot move a tuple
         * from being part of one relcache entry to being part of another.
         */
        if (tupleRelId == RelationRelationId)
        {
                Form_pg_class classtup = (Form_pg_class) GETSTRUCT(tuple);

                relationId = HeapTupleGetOid(tuple);
                if (classtup->relisshared)
                        databaseId = InvalidOid;
                else
                        databaseId = MyDatabaseId;
        }
        else if (tupleRelId == AttributeRelationId)
        {
                Form_pg_attribute atttup = (Form_pg_attribute) GETSTRUCT(tuple);

                relationId = atttup->attrelid;

                /*
                 * KLUGE ALERT: we always send the relcache event with MyDatabaseId,
                 * even if the rel in question is shared (which we can't easily tell).
                 * This essentially means that only backends in this same database
                 * will react to the relcache flush request.  This is in fact
                 * appropriate, since only those backends could see our pg_attribute
                 * change anyway.  It looks a bit ugly though.  (In practice, shared
                 * relations can't have schema changes after bootstrap, so we should
                 * never come here for a shared rel anyway.)
                 */
                databaseId = MyDatabaseId;
        }
        else if (tupleRelId == IndexRelationId)
        {
                Form_pg_index indextup = (Form_pg_index) GETSTRUCT(tuple);

                /*
                 * When a pg_index row is updated, we should send out a relcache inval
                 * for the index relation.  As above, we don't know the shared status
                 * of the index, but in practice it doesn't matter since indexes of
                 * shared catalogs can't have such updates.
                 */
                relationId = indextup->indexrelid;
                databaseId = MyDatabaseId;
        }
        else
                return;

        /*
         * Yes.  We need to register a relcache invalidation event.
         */
        RegisterRelcacheInvalidation(databaseId, relationId);
}

/*
 * CacheInvalidateCatalog
 *              Register invalidation of the whole content of a system catalog.
 *
 * This is normally used in VACUUM FULL/CLUSTER, where we haven't so much
 * changed any tuples as moved them around.  Some uses of catcache entries
 * expect their TIDs to be correct, so we have to blow away the entries.
 *
 * Note: we expect caller to verify that the rel actually is a system
 * catalog.  If it isn't, no great harm is done, just a wasted sinval message.
 */
void
CacheInvalidateCatalog(Oid catalogId)
{
        Oid                     databaseId;

        if (IsSharedRelation(catalogId))
                databaseId = InvalidOid;
        else
                databaseId = MyDatabaseId;

        RegisterCatalogInvalidation(databaseId, catalogId);
}

/*
 * CacheInvalidateRelcache
 *              Register invalidation of the specified relation's relcache entry
 *              at end of command.
 *
 * This is used in places that need to force relcache rebuild but aren't
 * changing any of the tuples recognized as contributors to the relcache
 * entry by CacheInvalidateHeapTuple.  (An example is dropping an index.)
 */
void
CacheInvalidateRelcache(Relation relation)
{
        Oid                     databaseId;
        Oid                     relationId;

        relationId = RelationGetRelid(relation);
        if (relation->rd_rel->relisshared)
                databaseId = InvalidOid;
        else
                databaseId = MyDatabaseId;

        RegisterRelcacheInvalidation(databaseId, relationId);
}

/*
 * CacheInvalidateRelcacheByTuple
 *              As above, but relation is identified by passing its pg_class tuple.
 */
void
CacheInvalidateRelcacheByTuple(HeapTuple classTuple)
{
        Form_pg_class classtup = (Form_pg_class) GETSTRUCT(classTuple);
        Oid                     databaseId;
        Oid                     relationId;

        relationId = HeapTupleGetOid(classTuple);
        if (classtup->relisshared)
                databaseId = InvalidOid;
        else
                databaseId = MyDatabaseId;
        RegisterRelcacheInvalidation(databaseId, relationId);
}

/*
 * CacheInvalidateRelcacheByRelid
 *              As above, but relation is identified by passing its OID.
 *              This is the least efficient of the three options; use one of
 *              the above routines if you have a Relation or pg_class tuple.
 */
void
CacheInvalidateRelcacheByRelid(Oid relid)
{
        HeapTuple       tup;

        tup = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
        if (!HeapTupleIsValid(tup))
                elog(ERROR, "cache lookup failed for relation %u", relid);
        CacheInvalidateRelcacheByTuple(tup);
        ReleaseSysCache(tup);
}


/*
 * CacheInvalidateSmgr
 *              Register invalidation of smgr references to a physical relation.
 *
 * Sending this type of invalidation msg forces other backends to close open
 * smgr entries for the rel.  This should be done to flush dangling open-file
 * references when the physical rel is being dropped or truncated.  Because
 * these are nontransactional (i.e., not-rollback-able) operations, we just
 * send the inval message immediately without any queuing.
 *
 * Note: in most cases there will have been a relcache flush issued against
 * the rel at the logical level.  We need a separate smgr-level flush because
 * it is possible for backends to have open smgr entries for rels they don't
 * have a relcache entry for, e.g. because the only thing they ever did with
 * the rel is write out dirty shared buffers.
 *
 * Note: because these messages are nontransactional, they won't be captured
 * in commit/abort WAL entries.  Instead, calls to CacheInvalidateSmgr()
 * should happen in low-level smgr.c routines, which are executed while
 * replaying WAL as well as when creating it.
 *
 * Note: In order to avoid bloating SharedInvalidationMessage, we store only
 * three bytes of the backend ID using what would otherwise be padding space.
 * Thus, the maximum possible backend ID is 2^23-1.
 */
void
CacheInvalidateSmgr(RelFileNodeBackend rnode)
{
        SharedInvalidationMessage msg;

        msg.sm.id = SHAREDINVALSMGR_ID;
        msg.sm.backend_hi = rnode.backend >> 16;
        msg.sm.backend_lo = rnode.backend & 0xffff;
        msg.sm.rnode = rnode.node;
        SendSharedInvalidMessages(&msg, 1);
}

/*
 * CacheInvalidateRelmap
 *              Register invalidation of the relation mapping for a database,
 *              or for the shared catalogs if databaseId is zero.
 *
 * Sending this type of invalidation msg forces other backends to re-read
 * the indicated relation mapping file.  It is also necessary to send a
 * relcache inval for the specific relations whose mapping has been altered,
 * else the relcache won't get updated with the new filenode data.
 *
 * Note: because these messages are nontransactional, they won't be captured
 * in commit/abort WAL entries.  Instead, calls to CacheInvalidateRelmap()
 * should happen in low-level relmapper.c routines, which are executed while
 * replaying WAL as well as when creating it.
 */
void
CacheInvalidateRelmap(Oid databaseId)
{
        SharedInvalidationMessage msg;

        msg.rm.id = SHAREDINVALRELMAP_ID;
        msg.rm.dbId = databaseId;
        SendSharedInvalidMessages(&msg, 1);
}


/*
 * CacheRegisterSyscacheCallback
 *              Register the specified function to be called for all future
 *              invalidation events in the specified cache.  The cache ID and the
 *              hash value of the tuple being invalidated will be passed to the
 *              function.
 *
 * NOTE: Hash value zero will be passed if a cache reset request is received.
 * In this case the called routines should flush all cached state.
 * Yes, there's a possibility of a false match to zero, but it doesn't seem
 * worth troubling over, especially since most of the current callees just
 * flush all cached state anyway.
 */
void
CacheRegisterSyscacheCallback(int cacheid,
                                                          SyscacheCallbackFunction func,
                                                          Datum arg)
{
        if (syscache_callback_count >= MAX_SYSCACHE_CALLBACKS)
                elog(FATAL, "out of syscache_callback_list slots");

        syscache_callback_list[syscache_callback_count].id = cacheid;
        syscache_callback_list[syscache_callback_count].function = func;
        syscache_callback_list[syscache_callback_count].arg = arg;

        ++syscache_callback_count;
}

/*
 * CacheRegisterRelcacheCallback
 *              Register the specified function to be called for all future
 *              relcache invalidation events.  The OID of the relation being
 *              invalidated will be passed to the function.
 *
 * NOTE: InvalidOid will be passed if a cache reset request is received.
 * In this case the called routines should flush all cached state.
 */
void
CacheRegisterRelcacheCallback(RelcacheCallbackFunction func,
                                                          Datum arg)
{
        if (relcache_callback_count >= MAX_RELCACHE_CALLBACKS)
                elog(FATAL, "out of relcache_callback_list slots");

        relcache_callback_list[relcache_callback_count].function = func;
        relcache_callback_list[relcache_callback_count].arg = arg;

        ++relcache_callback_count;
}

/*
 * CallSyscacheCallbacks
 *
 * This is exported so that CatalogCacheFlushCatalog can call it, saving
 * this module from knowing which catcache IDs correspond to which catalogs.
 */
void
CallSyscacheCallbacks(int cacheid, uint32 hashvalue)
{
        int                     i;

        for (i = 0; i < syscache_callback_count; i++)
        {
                struct SYSCACHECALLBACK *ccitem = syscache_callback_list + i;

                if (ccitem->id == cacheid)
                        (*ccitem->function) (ccitem->arg, cacheid, hashvalue);
        }
}