database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-19 15:49:24 +03:00
Code Activity

First phase of memory management rewrite (see backend/utils/mmgr/README

Browse Source 
for details).  It doesn't really do that much yet, since there are no
short-term memory contexts in the executor, but the infrastructure is
in place and long-term contexts are handled reasonably.  A few long-
standing bugs have been fixed, such as 'VACUUM; anything' in a single
query string crashing.  Also, out-of-memory is now considered a
recoverable ERROR, not FATAL.
Eliminate a large amount of crufty, now-dead code in and around
memory management.
Fix problem with holding off SIGTRAP, SIGSEGV, etc in postmaster and
backend startup.
This commit is contained in:
Tom Lane
2000-06-28 03:33:33 +00:00
parent b601c8d882
commit 1aebc3618a
74 changed files with 2325 additions and 3296 deletions
Download Patch File Download Diff File Expand all files Collapse all files

242
src/backend/tcop/postgres.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.161 2000/06/22 22:31:20 petere Exp $
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.162 2000/06/28 03:32:18 tgl Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@@ -79,7 +79,6 @@ bool Log_connections = false;
CommandDest whereToSendOutput = Debug;
extern void BaseInit(void);
extern void StartupXLOG(void);
extern void ShutdownXLOG(void);
@@ -88,10 +87,8 @@ extern void HandleDeadLock(SIGNAL_ARGS);
extern char XLogDir[];
extern char ControlFilePath[];
extern int lockingOff;
extern int NBuffers;
static bool dontExecute = false;
int dontExecute = 0;
static bool IsEmptyQuery = false;
/* note: these declarations had better match tcopprot.h */
@@ -101,8 +98,6 @@ bool Warn_restart_ready = false;
bool InError = false;
bool ExitAfterAbort = false;
extern int NBuffers;
static bool EchoQuery = false; /* default don't echo */
char pg_pathname[MAXPGPATH];
FILE *StatFp = NULL;
@@ -133,7 +128,6 @@ int XfuncMode = 0;
static int InteractiveBackend(StringInfo inBuf);
static int SocketBackend(StringInfo inBuf);
static int ReadCommand(StringInfo inBuf);
static void pg_exec_query(char *query_string);
static void SigHupHandler(SIGNAL_ARGS);
static void FloatExceptionHandler(SIGNAL_ARGS);
static void quickdie(SIGNAL_ARGS);
@@ -331,19 +325,12 @@ SocketBackend(StringInfo inBuf)
static int
ReadCommand(StringInfo inBuf)
{
MemoryContext oldcontext;
int result;
/*
* Make sure any expansion of inBuf happens in permanent memory
* context, so that we can keep using it for future command cycles.
*/
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
if (IsUnderPostmaster)
result = SocketBackend(inBuf);
else
result = InteractiveBackend(inBuf);
MemoryContextSwitchTo(oldcontext);
return result;
}
@@ -355,10 +342,9 @@ ReadCommand(StringInfo inBuf)
* multiple queries and/or the rewriter might expand one query to several.
*/
List *
pg_parse_and_rewrite(char *query_string, /* string to execute */
Oid *typev,/* argument types */
int nargs, /* number of arguments */
bool aclOverride)
pg_parse_and_rewrite(char *query_string, /* string to execute */
Oid *typev, /* parameter types */
int nargs) /* number of parameters */
{
List *querytree_list;
List *querytree_list_item;
@@ -422,30 +408,6 @@ pg_parse_and_rewrite(char *query_string, /* string to execute */
querytree_list = new_list;
/* ----------------
* (3) If ACL override is requested, mark queries for no ACL check.
* ----------------
*/
if (aclOverride)
{
foreach(querytree_list_item, querytree_list)
{
List *l;
querytree = (Query *) lfirst(querytree_list_item);
if (querytree->commandType == CMD_UTILITY)
continue;
foreach(l, querytree->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
rte->skipAcl = TRUE;
}
}
}
if (Debug_print_rewritten)
{
if (Debug_pretty_print)
@@ -516,63 +478,66 @@ pg_plan_query(Query *querytree)
/* ----------------------------------------------------------------
* pg_exec_query()
* pg_exec_query_dest()
*
* Takes a querystring, runs the parser/utilities or
* parser/planner/executor over it as necessary
* Begin Transaction Should have been called before this
* and CommitTransaction After this is called
* This is strictly because we do not allow for nested xactions.
* parser/planner/executor over it as necessary.
*
* NON-OBVIOUS-RESTRICTIONS
* this function _MUST_ allocate a new "parsetree" each time,
* since it may be stored in a named portal and should not
* change its value.
* Assumptions:
*
* Caller is responsible for calling StartTransactionCommand() beforehand
* and CommitTransactionCommand() afterwards (if successful).
*
* The CurrentMemoryContext at entry references a context that is
* appropriate for execution of individual queries (typically this will be
* TransactionCommandContext). Note that this routine resets that context
* after each individual query, so don't store anything there that
* must outlive the call!
*
* parse_context references a context suitable for holding the
* parse/rewrite trees (typically this will be QueryContext).
* This context must be longer-lived than the CurrentMemoryContext!
* In fact, if the query string might contain BEGIN/COMMIT commands,
* parse_context had better outlive TopTransactionContext!
*
* We could have hard-wired knowledge about QueryContext and
* TransactionCommandContext into this routine, but it seems better
* not to, in case callers from outside this module need to use some
* other contexts.
*
* ----------------------------------------------------------------
*/
static void
pg_exec_query(char *query_string)
{
pg_exec_query_dest(query_string, whereToSendOutput, FALSE);
}
#ifdef NOT_USED
void
pg_exec_query_acl_override(char *query_string)
{
pg_exec_query_dest(query_string, whereToSendOutput, TRUE);
}
#endif
void
pg_exec_query_dest(char *query_string, /* string to execute */
CommandDest dest, /* where results should go */
bool aclOverride) /* to give utility commands power
* of superusers */
MemoryContext parse_context) /* context for parsetrees */
{
List *querytree_list;
/* parse and rewrite the queries */
querytree_list = pg_parse_and_rewrite(query_string, NULL, 0,
aclOverride);
MemoryContext oldcontext;
List *querytree_list,
*querytree_item;
/*
* NOTE: we do not use "foreach" here because we want to be sure the
* list pointer has been advanced before the query is executed. We
* need to do that because VACUUM has a nasty little habit of doing
* CommitTransactionCommand at startup, and that will release the
* memory holding our parse list :-(. This needs a better solution
* --- currently, the code will crash if someone submits "vacuum;
* something-else" in a single query string. But memory allocation
* needs redesigned anyway, so this will have to do for now.
* Switch to appropriate context for constructing parsetrees.
*/
while (querytree_list)
{
Query *querytree = (Query *) lfirst(querytree_list);
oldcontext = MemoryContextSwitchTo(parse_context);
querytree_list = lnext(querytree_list);
/*
* Parse and rewrite the query or queries.
*/
querytree_list = pg_parse_and_rewrite(query_string, NULL, 0);
/*
* Switch back to execution context for planning and execution.
*/
MemoryContextSwitchTo(oldcontext);
/*
* Run through the query or queries and execute each one.
*/
foreach(querytree_item, querytree_list)
{
Query *querytree = (Query *) lfirst(querytree_item);
/* if we got a cancel signal in parsing or prior command, quit */
if (QueryCancel)
@@ -636,9 +601,17 @@ pg_exec_query_dest(char *query_string, /* string to execute */
if (Show_executor_stats)
ResetUsage();
if (DebugLvl > 1)
elog(DEBUG, "ProcessQuery");
ProcessQuery(querytree, plan, dest);
if (dontExecute)
{
/* don't execute it, just show the query plan */
print_plan(plan, querytree);
}
else
{
if (DebugLvl > 1)
elog(DEBUG, "ProcessQuery");
ProcessQuery(querytree, plan, dest);
}
if (Show_executor_stats)
{
@@ -652,8 +625,15 @@ pg_exec_query_dest(char *query_string, /* string to execute */
* between queries so that the effects of early queries are
* visible to subsequent ones.
*/
CommandCounterIncrement();
/*
* Also, clear the execution context to recover temporary
* memory used by the query. NOTE: if query string contains
* BEGIN/COMMIT transaction commands, execution context may
* now be different from what we were originally passed;
* so be careful to clear current context not "oldcontext".
*/
MemoryContextResetAndDeleteChildren(CurrentMemoryContext);
}
}
@@ -821,6 +801,17 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
extern char *optarg;
extern int DebugLvl;
/*
* Fire up essential subsystems: error and memory management
*
* If we are running under the postmaster, this is done already.
*/
if (!IsUnderPostmaster)
{
EnableExceptionHandling(true);
MemoryContextInit();
}
/*
* Set default values for command-line options.
*/
@@ -973,7 +964,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
break;
case 'i':
dontExecute = 1;
dontExecute = true;
break;
case 'L':
@@ -1182,11 +1173,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
*
* Note that postmaster already blocked ALL signals to make us happy.
*/
if (!IsUnderPostmaster)
{
PG_INITMASK();
PG_SETMASK(&BlockSig);
}
pqinitmask();
#ifdef HAVE_SIGPROCMASK
sigdelset(&BlockSig, SIGUSR1);
@@ -1194,6 +1181,8 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
BlockSig &= ~(sigmask(SIGUSR1));
#endif
PG_SETMASK(&BlockSig); /* block everything except SIGUSR1 */
pqsignal(SIGHUP, SigHupHandler); /* set flag to read config file */
pqsignal(SIGINT, QueryCancelHandler); /* cancel current query */
pqsignal(SIGQUIT, handle_warn); /* handle error */
@@ -1215,8 +1204,6 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
PG_SETMASK(&BlockSig); /* block everything except SIGUSR1 */
/*
* Get user name (needed now in case it is the default database name)
* and check command line validity
@@ -1360,13 +1347,6 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
on_shmem_exit(remove_all_temp_relations, NULL);
{
MemoryContext oldcontext = MemoryContextSwitchTo(TopMemoryContext);
parser_input = makeStringInfo(); /* initialize input buffer */
MemoryContextSwitchTo(oldcontext);
}
/*
* Send this backend's cancellation info to the frontend.
*/
@@ -1386,7 +1366,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
if (!IsUnderPostmaster)
{
puts("\nPOSTGRES backend interactive interface ");
puts("$Revision: 1.161 $ $Date: 2000/06/22 22:31:20 $\n");
puts("$Revision: 1.162 $ $Date: 2000/06/28 03:32:18 $\n");
}
/*
@@ -1397,6 +1377,20 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
SetProcessingMode(NormalProcessing);
/*
* Create the memory context we will use in the main loop.
*
* QueryContext is reset once per iteration of the main loop,
* ie, upon completion of processing of each supplied query string.
* It can therefore be used for any data that should live just as
* long as the query string --- parse trees, for example.
*/
QueryContext = AllocSetContextCreate(TopMemoryContext,
"QueryContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* POSTGRES main processing loop begins here
*
@@ -1406,18 +1400,30 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
if (sigsetjmp(Warn_restart, 1) != 0)
{
/* Make sure we are in a valid memory context */
MemoryContextSwitchTo(TopMemoryContext);
/*
* Make sure we are in a valid memory context during recovery.
*
* We use ErrorContext in hopes that it will have some free space
* even if we're otherwise up against it...
*/
MemoryContextSwitchTo(ErrorContext);
if (DebugLvl >= 1)
elog(DEBUG, "AbortCurrentTransaction");
AbortCurrentTransaction();
InError = false;
if (ExitAfterAbort)
{
ProcReleaseLocks(); /* Just to be sure... */
proc_exit(0);
}
/*
* If we recovered successfully, return to normal top-level context
* and clear ErrorContext for next time.
*/
MemoryContextSwitchTo(TopMemoryContext);
MemoryContextResetAndDeleteChildren(ErrorContext);
InError = false;
}
Warn_restart_ready = true; /* we can now handle elog(ERROR) */
@@ -1430,7 +1436,14 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
for (;;)
{
set_ps_display("idle");
/*
* Release storage left over from prior query cycle, and
* create a new query input buffer in the cleared QueryContext.
*/
MemoryContextSwitchTo(QueryContext);
MemoryContextResetAndDeleteChildren(QueryContext);
parser_input = makeStringInfo();
/* XXX this could be moved after ReadCommand below to get more
* sensical behaviour */
@@ -1462,6 +1475,8 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
* (3) read a command (loop blocks here)
* ----------------
*/
set_ps_display("idle");
firstchar = ReadCommand(parser_input);
QueryCancel = false; /* forget any earlier CANCEL signal */
@@ -1528,7 +1543,9 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
elog(DEBUG, "StartTransactionCommand");
StartTransactionCommand();
pg_exec_query(parser_input->data);
pg_exec_query_dest(parser_input->data,
whereToSendOutput,
QueryContext);
/*
* Invoke IMMEDIATE constraint triggers
@@ -1566,7 +1583,8 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
* (6) commit the current transaction
*
* Note: if we had an empty input buffer, then we didn't
* call pg_exec_query, so we don't bother to commit this transaction.
* call pg_exec_query_dest, so we don't bother to commit
* this transaction.
* ----------------
*/
if (!IsEmptyQuery)
@@ -1578,7 +1596,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
#ifdef SHOW_MEMORY_STATS
/* print global-context stats at each commit for leak tracking */
if (ShowStats)
GlobalMemoryStats();
MemoryContextStats(TopMemoryContext);
#endif
}
else