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Add wait event type "InjectionPoint", a custom type like "Extension".

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Both injection points and customization of type "Extension" are new in
v17, so this just changes a detail of an unreleased feature.

Reported by Robert Haas.  Reviewed by Michael Paquier.

Discussion: https://postgr.es/m/CA+TgmobfMU5pdXP36D5iAwxV5WKE_vuDLtp_1QyH+H5jMMt21g@mail.gmail.com
This commit is contained in:
Noah Misch
2024-06-27 19:21:05 -07:00
parent 0844b39689
commit bb93640a68
13 changed files with 215 additions and 131 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
src/backend/utils/activity/generate-wait_event_types.pl
View File

@@ -181,9 +181,10 @@ if ($gen_code)
foreach my $waitclass (sort { uc($a) cmp uc($b) } keys %hashwe)
{
# Don't generate the pgstat_wait_event.c and wait_event_types.h files
# for Extension, LWLock and Lock, these are handled independently.
# for types handled independently.
next
if ( $waitclass eq 'WaitEventExtension'
|| $waitclass eq 'WaitEventInjectionPoint'
|| $waitclass eq 'WaitEventLWLock'
|| $waitclass eq 'WaitEventLock');

243
src/backend/utils/activity/wait_event.c
View File

@@ -47,68 +47,69 @@ uint32 *my_wait_event_info = &local_my_wait_event_info;
* Hash tables for storing custom wait event ids and their names in
* shared memory.
*
* WaitEventExtensionHashById is used to find the name from an event id.
* Any backend can search it to find custom wait events.
* WaitEventCustomHashByInfo is used to find the name from wait event
* information. Any backend can search it to find custom wait events.
*
* WaitEventExtensionHashByName is used to find the event ID from a name.
* It is used to ensure that no duplicated entries are registered.
* WaitEventCustomHashByName is used to find the wait event information from a
* name. It is used to ensure that no duplicated entries are registered.
*
* For simplicity, we use the same ID counter across types of custom events.
* We could end that anytime the need arises.
*
* The size of the hash table is based on the assumption that
* WAIT_EVENT_EXTENSION_HASH_INIT_SIZE is enough for most cases, and it seems
* WAIT_EVENT_CUSTOM_HASH_INIT_SIZE is enough for most cases, and it seems
* unlikely that the number of entries will reach
* WAIT_EVENT_EXTENSION_HASH_MAX_SIZE.
* WAIT_EVENT_CUSTOM_HASH_MAX_SIZE.
*/
static HTAB *WaitEventExtensionHashById; /* find names from IDs */
static HTAB *WaitEventExtensionHashByName; /* find IDs from names */
static HTAB *WaitEventCustomHashByInfo; /* find names from infos */
static HTAB *WaitEventCustomHashByName; /* find infos from names */
#define WAIT_EVENT_EXTENSION_HASH_INIT_SIZE 16
#define WAIT_EVENT_EXTENSION_HASH_MAX_SIZE 128
#define WAIT_EVENT_CUSTOM_HASH_INIT_SIZE 16
#define WAIT_EVENT_CUSTOM_HASH_MAX_SIZE 128
/* hash table entries */
typedef struct WaitEventExtensionEntryById
typedef struct WaitEventCustomEntryByInfo
{
uint16 event_id; /* hash key */
uint32 wait_event_info; /* hash key */
char wait_event_name[NAMEDATALEN]; /* custom wait event name */
} WaitEventExtensionEntryById;
} WaitEventCustomEntryByInfo;
typedef struct WaitEventExtensionEntryByName
typedef struct WaitEventCustomEntryByName
{
char wait_event_name[NAMEDATALEN]; /* hash key */
uint16 event_id; /* wait event ID */
} WaitEventExtensionEntryByName;
uint32 wait_event_info;
} WaitEventCustomEntryByName;
/* dynamic allocation counter for custom wait events in extensions */
typedef struct WaitEventExtensionCounterData
/* dynamic allocation counter for custom wait events */
typedef struct WaitEventCustomCounterData
{
int nextId; /* next ID to assign */
slock_t mutex; /* protects the counter */
} WaitEventExtensionCounterData;
} WaitEventCustomCounterData;
/* pointer to the shared memory */
static WaitEventExtensionCounterData *WaitEventExtensionCounter;
static WaitEventCustomCounterData *WaitEventCustomCounter;
/* first event ID of custom wait events for extensions */
#define WAIT_EVENT_EXTENSION_INITIAL_ID 1
/* first event ID of custom wait events */
#define WAIT_EVENT_CUSTOM_INITIAL_ID 1
/* wait event info for extensions */
#define WAIT_EVENT_EXTENSION_INFO(eventId) (PG_WAIT_EXTENSION | eventId)
static const char *GetWaitEventExtensionIdentifier(uint16 eventId);
static uint32 WaitEventCustomNew(uint32 classId, const char *wait_event_name);
static const char *GetWaitEventCustomIdentifier(uint32 wait_event_info);
/*
* Return the space for dynamic shared hash tables and dynamic allocation counter.
*/
Size
WaitEventExtensionShmemSize(void)
WaitEventCustomShmemSize(void)
{
Size sz;
sz = MAXALIGN(sizeof(WaitEventExtensionCounterData));
sz = add_size(sz, hash_estimate_size(WAIT_EVENT_EXTENSION_HASH_MAX_SIZE,
sizeof(WaitEventExtensionEntryById)));
sz = add_size(sz, hash_estimate_size(WAIT_EVENT_EXTENSION_HASH_MAX_SIZE,
sizeof(WaitEventExtensionEntryByName)));
sz = MAXALIGN(sizeof(WaitEventCustomCounterData));
sz = add_size(sz, hash_estimate_size(WAIT_EVENT_CUSTOM_HASH_MAX_SIZE,
sizeof(WaitEventCustomEntryByInfo)));
sz = add_size(sz, hash_estimate_size(WAIT_EVENT_CUSTOM_HASH_MAX_SIZE,
sizeof(WaitEventCustomEntryByName)));
return sz;
}
@@ -116,39 +117,41 @@ WaitEventExtensionShmemSize(void)
* Allocate shmem space for dynamic shared hash and dynamic allocation counter.
*/
void
WaitEventExtensionShmemInit(void)
WaitEventCustomShmemInit(void)
{
bool found;
HASHCTL info;
WaitEventExtensionCounter = (WaitEventExtensionCounterData *)
ShmemInitStruct("WaitEventExtensionCounterData",
sizeof(WaitEventExtensionCounterData), &found);
WaitEventCustomCounter = (WaitEventCustomCounterData *)
ShmemInitStruct("WaitEventCustomCounterData",
sizeof(WaitEventCustomCounterData), &found);
if (!found)
{
/* initialize the allocation counter and its spinlock. */
WaitEventExtensionCounter->nextId = WAIT_EVENT_EXTENSION_INITIAL_ID;
SpinLockInit(&WaitEventExtensionCounter->mutex);
WaitEventCustomCounter->nextId = WAIT_EVENT_CUSTOM_INITIAL_ID;
SpinLockInit(&WaitEventCustomCounter->mutex);
}
/* initialize or attach the hash tables to store custom wait events */
info.keysize = sizeof(uint16);
info.entrysize = sizeof(WaitEventExtensionEntryById);
WaitEventExtensionHashById = ShmemInitHash("WaitEventExtension hash by id",
WAIT_EVENT_EXTENSION_HASH_INIT_SIZE,
WAIT_EVENT_EXTENSION_HASH_MAX_SIZE,
&info,
HASH_ELEM | HASH_BLOBS);
info.keysize = sizeof(uint32);
info.entrysize = sizeof(WaitEventCustomEntryByInfo);
WaitEventCustomHashByInfo =
ShmemInitHash("WaitEventCustom hash by wait event information",
WAIT_EVENT_CUSTOM_HASH_INIT_SIZE,
WAIT_EVENT_CUSTOM_HASH_MAX_SIZE,
&info,
HASH_ELEM | HASH_BLOBS);
/* key is a NULL-terminated string */
info.keysize = sizeof(char[NAMEDATALEN]);
info.entrysize = sizeof(WaitEventExtensionEntryByName);
WaitEventExtensionHashByName = ShmemInitHash("WaitEventExtension hash by name",
WAIT_EVENT_EXTENSION_HASH_INIT_SIZE,
WAIT_EVENT_EXTENSION_HASH_MAX_SIZE,
&info,
HASH_ELEM | HASH_STRINGS);
info.entrysize = sizeof(WaitEventCustomEntryByName);
WaitEventCustomHashByName =
ShmemInitHash("WaitEventCustom hash by name",
WAIT_EVENT_CUSTOM_HASH_INIT_SIZE,
WAIT_EVENT_CUSTOM_HASH_MAX_SIZE,
&info,
HASH_ELEM | HASH_STRINGS);
}
/*
@@ -159,11 +162,24 @@ WaitEventExtensionShmemInit(void)
*/
uint32
WaitEventExtensionNew(const char *wait_event_name)
{
return WaitEventCustomNew(PG_WAIT_EXTENSION, wait_event_name);
}
uint32
WaitEventInjectionPointNew(const char *wait_event_name)
{
return WaitEventCustomNew(PG_WAIT_INJECTIONPOINT, wait_event_name);
}
static uint32
WaitEventCustomNew(uint32 classId, const char *wait_event_name)
{
uint16 eventId;
bool found;
WaitEventExtensionEntryByName *entry_by_name;
WaitEventExtensionEntryById *entry_by_id;
WaitEventCustomEntryByName *entry_by_name;
WaitEventCustomEntryByInfo *entry_by_info;
uint32 wait_event_info;
/* Check the limit of the length of the event name */
if (strlen(wait_event_name) >= NAMEDATALEN)
@@ -175,13 +191,24 @@ WaitEventExtensionNew(const char *wait_event_name)
* Check if the wait event info associated to the name is already defined,
* and return it if so.
*/
LWLockAcquire(WaitEventExtensionLock, LW_SHARED);
entry_by_name = (WaitEventExtensionEntryByName *)
hash_search(WaitEventExtensionHashByName, wait_event_name,
LWLockAcquire(WaitEventCustomLock, LW_SHARED);
entry_by_name = (WaitEventCustomEntryByName *)
hash_search(WaitEventCustomHashByName, wait_event_name,
HASH_FIND, &found);
LWLockRelease(WaitEventExtensionLock);
LWLockRelease(WaitEventCustomLock);
if (found)
return WAIT_EVENT_EXTENSION_INFO(entry_by_name->event_id);
{
uint32 oldClassId;
oldClassId = entry_by_name->wait_event_info & WAIT_EVENT_CLASS_MASK;
if (oldClassId != classId)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("wait event \"%s\" already exists in type \"%s\"",
wait_event_name,
pgstat_get_wait_event_type(entry_by_name->wait_event_info))));
return entry_by_name->wait_event_info;
}
/*
* Allocate and register a new wait event. Recheck if the event name
@@ -189,113 +216,123 @@ WaitEventExtensionNew(const char *wait_event_name)
* one with the same name since the LWLock acquired again here was
* previously released.
*/
LWLockAcquire(WaitEventExtensionLock, LW_EXCLUSIVE);
entry_by_name = (WaitEventExtensionEntryByName *)
hash_search(WaitEventExtensionHashByName, wait_event_name,
LWLockAcquire(WaitEventCustomLock, LW_EXCLUSIVE);
entry_by_name = (WaitEventCustomEntryByName *)
hash_search(WaitEventCustomHashByName, wait_event_name,
HASH_FIND, &found);
if (found)
{
LWLockRelease(WaitEventExtensionLock);
return WAIT_EVENT_EXTENSION_INFO(entry_by_name->event_id);
uint32 oldClassId;
LWLockRelease(WaitEventCustomLock);
oldClassId = entry_by_name->wait_event_info & WAIT_EVENT_CLASS_MASK;
if (oldClassId != classId)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("wait event \"%s\" already exists in type \"%s\"",
wait_event_name,
pgstat_get_wait_event_type(entry_by_name->wait_event_info))));
return entry_by_name->wait_event_info;
}
/* Allocate a new event Id */
SpinLockAcquire(&WaitEventExtensionCounter->mutex);
SpinLockAcquire(&WaitEventCustomCounter->mutex);
if (WaitEventExtensionCounter->nextId >= WAIT_EVENT_EXTENSION_HASH_MAX_SIZE)
if (WaitEventCustomCounter->nextId >= WAIT_EVENT_CUSTOM_HASH_MAX_SIZE)
{
SpinLockRelease(&WaitEventExtensionCounter->mutex);
SpinLockRelease(&WaitEventCustomCounter->mutex);
ereport(ERROR,
errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("too many wait events for extensions"));
errmsg("too many custom wait events"));
}
eventId = WaitEventExtensionCounter->nextId++;
eventId = WaitEventCustomCounter->nextId++;
SpinLockRelease(&WaitEventExtensionCounter->mutex);
SpinLockRelease(&WaitEventCustomCounter->mutex);
/* Register the new wait event */
entry_by_id = (WaitEventExtensionEntryById *)
hash_search(WaitEventExtensionHashById, &eventId,
wait_event_info = classId | eventId;
entry_by_info = (WaitEventCustomEntryByInfo *)
hash_search(WaitEventCustomHashByInfo, &wait_event_info,
HASH_ENTER, &found);
Assert(!found);
strlcpy(entry_by_id->wait_event_name, wait_event_name,
sizeof(entry_by_id->wait_event_name));
strlcpy(entry_by_info->wait_event_name, wait_event_name,
sizeof(entry_by_info->wait_event_name));
entry_by_name = (WaitEventExtensionEntryByName *)
hash_search(WaitEventExtensionHashByName, wait_event_name,
entry_by_name = (WaitEventCustomEntryByName *)
hash_search(WaitEventCustomHashByName, wait_event_name,
HASH_ENTER, &found);
Assert(!found);
entry_by_name->event_id = eventId;
entry_by_name->wait_event_info = wait_event_info;
LWLockRelease(WaitEventExtensionLock);
LWLockRelease(WaitEventCustomLock);
return WAIT_EVENT_EXTENSION_INFO(eventId);
return wait_event_info;
}
/*
* Return the name of an wait event ID for extension.
* Return the name of a custom wait event information.
*/
static const char *
GetWaitEventExtensionIdentifier(uint16 eventId)
GetWaitEventCustomIdentifier(uint32 wait_event_info)
{
bool found;
WaitEventExtensionEntryById *entry;
WaitEventCustomEntryByInfo *entry;
/* Built-in event? */
if (eventId < WAIT_EVENT_EXTENSION_INITIAL_ID)
if (wait_event_info == PG_WAIT_EXTENSION)
return "Extension";
/* It is a user-defined wait event, so lookup hash table. */
LWLockAcquire(WaitEventExtensionLock, LW_SHARED);
entry = (WaitEventExtensionEntryById *)
hash_search(WaitEventExtensionHashById, &eventId,
LWLockAcquire(WaitEventCustomLock, LW_SHARED);
entry = (WaitEventCustomEntryByInfo *)
hash_search(WaitEventCustomHashByInfo, &wait_event_info,
HASH_FIND, &found);
LWLockRelease(WaitEventExtensionLock);
LWLockRelease(WaitEventCustomLock);
if (!entry)
elog(ERROR, "could not find custom wait event name for ID %u",
eventId);
elog(ERROR,
"could not find custom name for wait event information %u",
wait_event_info);
return entry->wait_event_name;
}
/*
* Returns a list of currently defined custom wait event names for extensions.
* The result is a palloc'd array, with the number of elements saved in
* *nwaitevents.
* Returns a list of currently defined custom wait event names. The result is
* a palloc'd array, with the number of elements saved in *nwaitevents.
*/
char **
GetWaitEventExtensionNames(int *nwaitevents)
GetWaitEventCustomNames(uint32 classId, int *nwaitevents)
{
char **waiteventnames;
WaitEventExtensionEntryByName *hentry;
WaitEventCustomEntryByName *hentry;
HASH_SEQ_STATUS hash_seq;
int index;
int els;
LWLockAcquire(WaitEventExtensionLock, LW_SHARED);
LWLockAcquire(WaitEventCustomLock, LW_SHARED);
/* Now we can safely count the number of entries */
els = hash_get_num_entries(WaitEventExtensionHashByName);
els = hash_get_num_entries(WaitEventCustomHashByName);
/* Allocate enough space for all entries */
waiteventnames = palloc(els * sizeof(char *));
/* Now scan the hash table to copy the data */
hash_seq_init(&hash_seq, WaitEventExtensionHashByName);
hash_seq_init(&hash_seq, WaitEventCustomHashByName);
index = 0;
while ((hentry = (WaitEventExtensionEntryByName *) hash_seq_search(&hash_seq)) != NULL)
while ((hentry = (WaitEventCustomEntryByName *) hash_seq_search(&hash_seq)) != NULL)
{
if ((hentry->wait_event_info & WAIT_EVENT_CLASS_MASK) != classId)
continue;
waiteventnames[index] = pstrdup(hentry->wait_event_name);
index++;
}
LWLockRelease(WaitEventExtensionLock);
Assert(index == els);
LWLockRelease(WaitEventCustomLock);
*nwaitevents = index;
return waiteventnames;
@@ -374,6 +411,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
case PG_WAIT_IO:
event_type = "IO";
break;
case PG_WAIT_INJECTIONPOINT:
event_type = "InjectionPoint";
break;
default:
event_type = "???";
break;
@@ -411,7 +451,8 @@ pgstat_get_wait_event(uint32 wait_event_info)
event_name = GetLockNameFromTagType(eventId);
break;
case PG_WAIT_EXTENSION:
event_name = GetWaitEventExtensionIdentifier(eventId);
case PG_WAIT_INJECTIONPOINT:
event_name = GetWaitEventCustomIdentifier(wait_event_info);
break;
case PG_WAIT_BUFFERPIN:
{

31
src/backend/utils/activity/wait_event_funcs.c
View File

@@ -48,7 +48,7 @@ pg_get_wait_events(PG_FUNCTION_ARGS)
#define PG_GET_WAIT_EVENTS_COLS 3
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
char **waiteventnames;
int nbextwaitevents;
int nbwaitevents;
/* Build tuplestore to hold the result rows */
InitMaterializedSRF(fcinfo, 0);
@@ -67,9 +67,10 @@ pg_get_wait_events(PG_FUNCTION_ARGS)
}
/* Handle custom wait events for extensions */
waiteventnames = GetWaitEventExtensionNames(&nbextwaitevents);
waiteventnames = GetWaitEventCustomNames(PG_WAIT_EXTENSION,
&nbwaitevents);
for (int idx = 0; idx < nbextwaitevents; idx++)
for (int idx = 0; idx < nbwaitevents; idx++)
{
StringInfoData buf;
Datum values[PG_GET_WAIT_EVENTS_COLS] = {0};
@@ -89,5 +90,29 @@ pg_get_wait_events(PG_FUNCTION_ARGS)
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
}
/* Likewise for injection points */
waiteventnames = GetWaitEventCustomNames(PG_WAIT_INJECTIONPOINT,
&nbwaitevents);
for (int idx = 0; idx < nbwaitevents; idx++)
{
StringInfoData buf;
Datum values[PG_GET_WAIT_EVENTS_COLS] = {0};
bool nulls[PG_GET_WAIT_EVENTS_COLS] = {0};
values[0] = CStringGetTextDatum("InjectionPoint");
values[1] = CStringGetTextDatum(waiteventnames[idx]);
initStringInfo(&buf);
appendStringInfo(&buf,
"Waiting for injection point \"%s\"",
waiteventnames[idx]);
values[2] = CStringGetTextDatum(buf.data);
tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
}
return (Datum) 0;
}

2
src/backend/utils/activity/wait_event_names.txt
View File

@@ -340,7 +340,7 @@ LogicalRepWorker "Waiting to read or update the state of logical replication wor
XactTruncation "Waiting to execute <function>pg_xact_status</function> or update the oldest transaction ID available to it."
WrapLimitsVacuum "Waiting to update limits on transaction id and multixact consumption."
NotifyQueueTail "Waiting to update limit on <command>NOTIFY</command> message storage."
WaitEventExtension "Waiting to read or update custom wait events information for extensions."
WaitEventCustom "Waiting to read or update custom wait events information."
WALSummarizer "Waiting to read or update WAL summarization state."
DSMRegistry "Waiting to read or update the dynamic shared memory registry."
InjectionPoint "Waiting to read or update information related to injection points."