static void
collectLocalMemoryStats(QueryDesc *queryDesc, int eflags)
{
BackendMemoryStat *myStat;
MemoryContextIteratorState state;
if (prev_ExecutorStart)
prev_ExecutorStart(queryDesc, eflags);
else
standard_ExecutorStart(queryDesc, eflags);
if (MyBackendProcNo < 0)
{
on_proc_exit(cleanupMyStat, 0);
MyBackendProcNo = MyProc->pgprocno;
Assert(MyBackendProcNo >= 0);
}
if (checkTick() == false)
return;
Assert(MyBackendProcNo < PROCARRAY_MAXPROCS);
myStat = NthBMS(MyBackendProcNo);
/*
* do not wait if reader currently locks our slot
*/
if (LWLockConditionalAcquire(myStat->lock, LW_EXCLUSIVE) == false)
return;
myStat->pid = MyProc->pid;
myStat->nContext = 0;
state.context = TopMemoryContext;
state.level = 0;
/*
* walk through all memory context and fill stat table in shared memory
*/
do {
MemoryContextStat *mcs = myStat->stats + myStat->nContext;
int namelen = strlen(state.context->name);
if (namelen > NAMEDATALEN - 1)
namelen = NAMEDATALEN - 1;
memcpy(mcs->name.data, state.context->name, namelen);
mcs->name.data[namelen] = '\0';
mcs->level = state.level;
getMemoryContextStat(state.context, &mcs->stat);
myStat->nContext++;
iterateMemoryContext(&state);
} while (state.context && myStat->nContext < N_MC_STAT);
LWLockRelease(myStat->lock);
}
/*
* CS186: Called when the specified buffer is unpinned and becomes
* available for replacement.
*/
void
BufferUnpinned(int bufIndex)
{
volatile BufferDesc *buf = &BufferDescriptors[bufIndex];
if (!LWLockConditionalAcquire(BufFreelistLock, LW_EXCLUSIVE))
return;
/*
* CS186 TODO: When this function is called, the specified buffer has
* just been unpinned. That means you can start to manage this buffer
* using your buffer replacement policy. You can access the
* StrategyControl global variable from inside this function.
* This function was added by the GSIs.
*/
if (BufferReplacementPolicy == POLICY_LRU || BufferReplacementPolicy == POLICY_MRU) {
UnpinnedHelper(&buf, &(StrategyControl->head), &(StrategyControl->tail));
}
else if (BufferReplacementPolicy == POLICY_2Q) {
if (buf->queueTag == 2) {
UnpinnedHelper(&buf, &(StrategyControl->head), &(StrategyControl->tail));
}
else if (buf->queueTag == 1) {
// Removes buf from A1 queue
if (StrategyControl->head2Q == StrategyControl->tail2Q) {
StrategyControl->head2Q = NULL;
StrategyControl->tail2Q = NULL;
}
else {
buf->prev->next = buf->next;
buf->next->prev = buf->prev;
if (buf == StrategyControl->head2Q) {
StrategyControl->head2Q = buf->next;
}
else if (buf == StrategyControl->tail2Q) {
StrategyControl->tail2Q= buf->prev;
}
}
// Put buff on Am queue
buf->queueTag = 2;
buf->next = NULL;
buf->prev = NULL;
UnpinnedHelper(&buf, &(StrategyControl->head), &(StrategyControl->tail));
}
// first time unpinning
else {
buf->queueTag = 1;
UnpinnedHelper(&buf, &(StrategyControl->head2Q), &(StrategyControl->tail2Q));
}
}
LWLockRelease(BufFreelistLock);
}
/*
* CS186: Called when the specified buffer is unpinned and becomes
* available for replacement.
*/
void
BufferUnpinned(int bufIndex)
{
volatile BufferDesc *buf = &BufferDescriptors[bufIndex];
//lock the buffer?
if (!LWLockConditionalAcquire(BufFreelistLock, LW_EXCLUSIVE))
return;
/*
* CS186 TODO: When this function is called, the specified buffer has
* just been unpinned. That means you can start to manage this buffer
* using your buffer replacement policy. You can access the
* StrategyControl global variable from inside this function.
* This function was added by the GSIs.
*/
if(BufferReplacementPolicy == POLICY_2Q){
if(buf->inList == true){
removeFromList(buf);
addToList(buf);
}
else if(buf->inA1 == true){
removeFromA1(buf);
addToList(buf);
}
else{
addToA1(buf);
}
}
else{
if(buf->inList == true){
removeFromList(buf);
}
addToList(buf);
}
LWLockRelease(BufFreelistLock);
}
/*
* Wait for any active I/O on a page slot to finish. (This does not
* guarantee that new I/O hasn't been started before we return, though.)
*
* Control lock must be held at entry, and will be held at exit.
*/
static void
SimpleLruWaitIO(SlruCtl ctl, int slotno)
{
SlruShared shared = ctl->shared;
/* See notes at top of file */
LWLockRelease(shared->ControlLock);
LWLockAcquire(shared->buffer_locks[slotno], LW_SHARED);
LWLockRelease(shared->buffer_locks[slotno]);
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
/*
* If the slot is still in an io-in-progress state, then either someone
* already started a new I/O on the slot, or a previous I/O failed and
* neglected to reset the page state. That shouldn't happen, really, but
* it seems worth a few extra cycles to check and recover from it. We can
* cheaply test for failure by seeing if the buffer lock is still held (we
* assume that transaction abort would release the lock).
*/
if (shared->page_status[slotno] == SLRU_PAGE_READ_IN_PROGRESS ||
shared->page_status[slotno] == SLRU_PAGE_WRITE_IN_PROGRESS)
{
if (LWLockConditionalAcquire(shared->buffer_locks[slotno], LW_SHARED))
{
/* indeed, the I/O must have failed */
if (shared->page_status[slotno] == SLRU_PAGE_READ_IN_PROGRESS)
shared->page_status[slotno] = SLRU_PAGE_EMPTY;
else
/* write_in_progress */
{
shared->page_status[slotno] = SLRU_PAGE_VALID;
shared->page_dirty[slotno] = true;
}
LWLockRelease(shared->buffer_locks[slotno]);
}
}
}
/*
* ss_report_location --- update the current scan location
*
* Writes an entry into the shared Sync Scan state of the form
* (relfilenode, blocknumber), overwriting any existing entry for the
* same relfilenode.
*/
void
ss_report_location(Relation rel, BlockNumber location)
{
#ifdef TRACE_SYNCSCAN
if (trace_syncscan)
{
if ((location % 1024) == 0)
elog(LOG,
"SYNC_SCAN: scanning \"%s\" at %u",
RelationGetRelationName(rel), location);
}
#endif
/*
* To reduce lock contention, only report scan progress every N pages. For
* the same reason, don't block if the lock isn't immediately available.
* Missing a few updates isn't critical, it just means that a new scan
* that wants to join the pack will start a little bit behind the head of
* the scan. Hopefully the pages are still in OS cache and the scan
* catches up quickly.
*/
if ((location % SYNC_SCAN_REPORT_INTERVAL) == 0)
{
if (LWLockConditionalAcquire(SyncScanLock, LW_EXCLUSIVE))
{
(void) ss_search(rel->rd_node, location, true);
LWLockRelease(SyncScanLock);
}
#ifdef TRACE_SYNCSCAN
else if (trace_syncscan)
elog(LOG,
"SYNC_SCAN: missed update for \"%s\" at %u",
RelationGetRelationName(rel), location);
#endif
}
}
/*
* Write a page from a shared buffer, if necessary.
* Does nothing if the specified slot is not dirty.
*
* NOTE: only one write attempt is made here. Hence, it is possible that
* the page is still dirty at exit (if someone else re-dirtied it during
* the write). However, we *do* attempt a fresh write even if the page
* is already being written; this is for checkpoints.
*
* Control lock must be held at entry, and will be held at exit.
*/
void
SimpleLruWritePage(SlruCtl ctl, int slotno, SlruFlush fdata)
{
SlruShared shared = ctl->shared;
int pageno;
bool ok;
/* Do nothing if page does not need writing */
if (shared->page_status[slotno] != SLRU_PAGE_DIRTY &&
shared->page_status[slotno] != SLRU_PAGE_WRITE_IN_PROGRESS)
return;
pageno = shared->page_number[slotno];
/*
* We must grab the per-buffer lock to do I/O. To avoid deadlock, must
* release ControlLock while waiting for per-buffer lock. Fortunately,
* most of the time the per-buffer lock shouldn't be already held, so we
* can do this:
*/
if (!LWLockConditionalAcquire(shared->buffer_locks[slotno],
LW_EXCLUSIVE))
{
LWLockRelease(shared->ControlLock);
LWLockAcquire(shared->buffer_locks[slotno], LW_EXCLUSIVE);
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
}
/*
* Check to see if someone else already did the write, or took the buffer
* away from us. If so, do nothing. NOTE: we really should never see
* WRITE_IN_PROGRESS here, since that state should only occur while the
* writer is holding the buffer lock. But accept it so that we have a
* recovery path if a writer aborts.
*/
if (shared->page_number[slotno] != pageno ||
(shared->page_status[slotno] != SLRU_PAGE_DIRTY &&
shared->page_status[slotno] != SLRU_PAGE_WRITE_IN_PROGRESS))
{
LWLockRelease(shared->buffer_locks[slotno]);
return;
}
/*
* Mark the slot write-busy. After this point, a transaction status
* update on this page will mark it dirty again.
*/
shared->page_status[slotno] = SLRU_PAGE_WRITE_IN_PROGRESS;
/* Okay, release the control lock and do the write */
LWLockRelease(shared->ControlLock);
ok = SlruPhysicalWritePage(ctl, pageno, slotno, fdata);
/* If we failed, and we're in a flush, better close the files */
if (!ok && fdata)
{
int i;
for (i = 0; i < fdata->num_files; i++)
close(fdata->fd[i]);
}
/* Re-acquire shared control lock and update page state */
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
Assert(shared->page_number[slotno] == pageno &&
(shared->page_status[slotno] == SLRU_PAGE_WRITE_IN_PROGRESS ||
shared->page_status[slotno] == SLRU_PAGE_DIRTY));
/* Cannot set CLEAN if someone re-dirtied page since write started */
if (shared->page_status[slotno] == SLRU_PAGE_WRITE_IN_PROGRESS)
shared->page_status[slotno] = ok ? SLRU_PAGE_CLEAN : SLRU_PAGE_DIRTY;
LWLockRelease(shared->buffer_locks[slotno]);
/* Now it's okay to ereport if we failed */
if (!ok)
SlruReportIOError(ctl, pageno, InvalidTransactionId);
}
/*
* Find a page in a shared buffer, reading it in if necessary.
* The page number must correspond to an already-initialized page.
*
* The passed-in xid is used only for error reporting, and may be
* InvalidTransactionId if no specific xid is associated with the action.
*
* Return value is the shared-buffer slot number now holding the page.
* The buffer's LRU access info is updated.
*
* Control lock must be held at entry, and will be held at exit.
*/
int
SimpleLruReadPage(SlruCtl ctl, int pageno, TransactionId xid)
{
SlruShared shared = ctl->shared;
/* Outer loop handles restart if we lose the buffer to someone else */
for (;;)
{
int slotno;
bool ok;
/* See if page already is in memory; if not, pick victim slot */
slotno = SlruSelectLRUPage(ctl, pageno);
/* Did we find the page in memory? */
if (shared->page_number[slotno] == pageno &&
shared->page_status[slotno] != SLRU_PAGE_EMPTY)
{
/* If page is still being read in, we cannot use it yet */
if (shared->page_status[slotno] != SLRU_PAGE_READ_IN_PROGRESS)
{
/* otherwise, it's ready to use */
SlruRecentlyUsed(shared, slotno);
return slotno;
}
}
else
{
/* We found no match; assert we selected a freeable slot */
Assert(shared->page_status[slotno] == SLRU_PAGE_EMPTY ||
shared->page_status[slotno] == SLRU_PAGE_CLEAN);
}
/* Mark the slot read-busy (no-op if it already was) */
shared->page_number[slotno] = pageno;
shared->page_status[slotno] = SLRU_PAGE_READ_IN_PROGRESS;
/*
* Temporarily mark page as recently-used to discourage
* SlruSelectLRUPage from selecting it again for someone else.
*/
SlruRecentlyUsed(shared, slotno);
/*
* We must grab the per-buffer lock to do I/O. To avoid deadlock,
* must release ControlLock while waiting for per-buffer lock.
* Fortunately, most of the time the per-buffer lock shouldn't be
* already held, so we can do this:
*/
if (!LWLockConditionalAcquire(shared->buffer_locks[slotno],
LW_EXCLUSIVE))
{
LWLockRelease(shared->ControlLock);
LWLockAcquire(shared->buffer_locks[slotno], LW_EXCLUSIVE);
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
}
/*
* Check to see if someone else already did the read, or took the
* buffer away from us. If so, restart from the top.
*/
if (shared->page_number[slotno] != pageno ||
shared->page_status[slotno] != SLRU_PAGE_READ_IN_PROGRESS)
{
LWLockRelease(shared->buffer_locks[slotno]);
continue;
}
/* Okay, release control lock and do the read */
LWLockRelease(shared->ControlLock);
ok = SlruPhysicalReadPage(ctl, pageno, slotno);
/* Re-acquire shared control lock and update page state */
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
Assert(shared->page_number[slotno] == pageno &&
shared->page_status[slotno] == SLRU_PAGE_READ_IN_PROGRESS);
shared->page_status[slotno] = ok ? SLRU_PAGE_CLEAN : SLRU_PAGE_EMPTY;
LWLockRelease(shared->buffer_locks[slotno]);
/* Now it's okay to ereport if we failed */
if (!ok)
SlruReportIOError(ctl, pageno, xid);
SlruRecentlyUsed(shared, slotno);
return slotno;
}
}
void
CheckForQDMirroringWork(void)
{
QDMIRRORUpdateMask updateMask;
bool validFlag;
QDMIRRORState state;
QDMIRRORDisabledReason disabledReason;
struct timeval lastLogTimeVal;
char errorMessage[QDMIRRORErrorMessageSize];
if (ftsQDMirrorInfo == NULL)
return;
/*
* Test without taking lock.
*/
if (ftsQDMirrorInfo->updateMask == QDMIRROR_UPDATEMASK_NONE)
return;
if (IsTransactionOrTransactionBlock())
return;
/*
* NOTE: We are trying to use the longer-term update config lock here.
*/
if (!LWLockConditionalAcquire(ftsQDMirrorUpdateConfigLock, LW_EXCLUSIVE))
return;
LWLockAcquire(ftsQDMirrorLock, LW_EXCLUSIVE);
if (ftsQDMirrorInfo->updateMask == QDMIRROR_UPDATEMASK_NONE)
{
LWLockRelease(ftsQDMirrorLock);
LWLockRelease(ftsQDMirrorUpdateConfigLock);
return;
}
updateMask = ftsQDMirrorInfo->updateMask;
ftsQDMirrorInfo->updateMask = QDMIRROR_UPDATEMASK_NONE;
validFlag = false;
if ((updateMask & QDMIRROR_UPDATEMASK_VALIDFLAG) != 0)
{
validFlag = !ftsQDMirrorInfo->valid;
/*
* Assume we are successful...
*/
ftsQDMirrorInfo->valid = validFlag;
}
state = ftsQDMirrorInfo->state;
disabledReason = ftsQDMirrorInfo->disabledReason;
lastLogTimeVal = ftsQDMirrorInfo->lastLogTimeVal;
strcpy(errorMessage, ftsQDMirrorInfo->errorMessage);
LWLockRelease(ftsQDMirrorLock);
QDMirroringUpdate(updateMask, validFlag,
state, disabledReason, &lastLogTimeVal, errorMessage);
LWLockRelease(ftsQDMirrorUpdateConfigLock);
}
void BufferUnpinned(int bufIndex)
{
volatile BufferDesc *buf = &BufferDescriptors[bufIndex];
volatile BufferDesc *first = StrategyControl->firstUnpinned;
volatile BufferDesc *last= StrategyControl->lastUnpinned;
volatile BufferDesc *previous = buf->previous;
volatile BufferDesc *next = buf->next;
if (!LWLockConditionalAcquire(BufFreelistLock, LW_EXCLUSIVE))
return;
if (BufferReplacementPolicy == POLICY_2Q) {
//2Q stuff
//if buf is on the AM queue then put buf on the front of the Am queue
volatile BufferDesc *head = first;
while (head != NULL) {
if (head == buf) {
//buf in AM queue, putting at the tail of AM queue
//if it's in the queue, assume firstUnpinned and lastUnpinned have been set
if (next != NULL) {
if (previous != NULL) { // buf in middle of AM queue
previous->next = next;
next->previous = previous;
last->next = buf;
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
} else { // buf at beginning
next->previous = NULL;
StrategyControl->firstUnpinned = next;
last->next = buf;
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
}
}
LWLockRelease(BufFreelistLock);
return;
} else {
head = head->next;
}
}
//else if buf is on the A1 queue then
head = StrategyControl->a1Head;
while (head != NULL) {
if (head == buf) {
//remove buf from the A1 queue
//put buf on the front of the Am queue
if (next != NULL) {
if (previous != NULL) { // buf in middle of A1 queue
previous->next = next;
next->previous = previous;
// if AM empty
if (first == NULL || last == NULL) {
StrategyControl->firstUnpinned = buf;
} else {
last->next = buf;
}
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
} else { // buf at beginning
next->previous = NULL;
StrategyControl->a1Head = next;
//if AM empty
if (first == NULL || last == NULL) {
StrategyControl->firstUnpinned = buf;
} else {
last->next = buf;
}
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
}
} else if (previous == NULL) { // buf is only thing in A1
StrategyControl->a1Head = NULL;
StrategyControl->a1Tail = NULL;
if (first == NULL || last == NULL) {
StrategyControl->firstUnpinned = buf;
} else {
last->next = buf;
}
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
} else { // buf is last thing in A1
StrategyControl->a1Tail = previous;
previous->next = NULL;
if (first == NULL || last == NULL) {
StrategyControl->firstUnpinned = buf;
} else {
last->next = buf;
}
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
}
LWLockRelease(BufFreelistLock);
return;
} else {
head = head->next;
}
}
//else
//put buf on the front of the A1 queue
if (StrategyControl->a1Head == NULL || StrategyControl->a1Tail == NULL) {
StrategyControl->a1Head = buf;
StrategyControl->a1Tail = buf;
buf->previous = NULL;
} else {
StrategyControl->a1Tail->next = buf;
buf->previous = StrategyControl->a1Tail;
}
buf->next = NULL;
StrategyControl->a1Tail = buf;
} else {
//LRU or MRU or Clock
if (next != NULL) {
if (previous != NULL) { //next and prev != null, buf is already in middle of list
previous->next = next;
next->previous = previous;
last->next = buf;
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
} else { //next != null, prev == null, buf is at beginning of list
next->previous = NULL;
StrategyControl->firstUnpinned = next;
last->next = buf;
buf->previous = last;
buf->next = NULL;
StrategyControl->lastUnpinned = buf;
}
} else if (previous == NULL) { //next == NULL, prev == null, buf is new to list
if (first == NULL) { // if first time, then set firstUnpinned to this buffer
StrategyControl->firstUnpinned = buf;
}
buf->previous = last;
buf->next = NULL;
if (last != NULL) {
last->next = buf;
}
StrategyControl->lastUnpinned = buf;
}
}
LWLockRelease(BufFreelistLock);
}
