greenplumn misc 源码
greenplumn misc 代码
文件路径：/src/backend/utils/adt/misc.c
/*-------------------------------------------------------------------------
*
* misc.c
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/adt/misc.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/file.h>
#include <dirent.h>
#include <math.h>
#include <unistd.h>
#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/catalog.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "commands/tablespace.h"
#include "common/keywords.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "parser/scansup.h"
#include "postmaster/syslogger.h"
#include "rewrite/rewriteHandler.h"
#include "storage/fd.h"
#include "utils/lsyscache.h"
#include "utils/ruleutils.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/timestamp.h"
#include "catalog/pg_authid.h"
#include "postmaster/fts.h"
#include "storage/pmsignal.h"
#include "storage/procarray.h"
#include "utils/backend_cancel.h"
/*
* Common subroutine for num_nulls() and num_nonnulls().
* Returns true if successful, false if function should return NULL.
* If successful, total argument count and number of nulls are
* returned into *nargs and *nulls.
*/
static bool
count_nulls(FunctionCallInfo fcinfo,
int32 *nargs, int32 *nulls)
{
int32 count = 0;
int i;
/* Did we get a VARIADIC array argument, or separate arguments? */
if (get_fn_expr_variadic(fcinfo->flinfo))
{
ArrayType *arr;
int ndims,
nitems,
*dims;
bits8 *bitmap;
Assert(PG_NARGS() == 1);
/*
* If we get a null as VARIADIC array argument, we can't say anything
* useful about the number of elements, so return NULL. This behavior
* is consistent with other variadic functions - see concat_internal.
*/
if (PG_ARGISNULL(0))
return false;
/*
* Non-null argument had better be an array. We assume that any call
* context that could let get_fn_expr_variadic return true will have
* checked that a VARIADIC-labeled parameter actually is an array. So
* it should be okay to just Assert that it's an array rather than
* doing a full-fledged error check.
*/
Assert(OidIsValid(get_base_element_type(get_fn_expr_argtype(fcinfo->flinfo, 0))));
/* OK, safe to fetch the array value */
arr = PG_GETARG_ARRAYTYPE_P(0);
/* Count the array elements */
ndims = ARR_NDIM(arr);
dims = ARR_DIMS(arr);
nitems = ArrayGetNItems(ndims, dims);
/* Count those that are NULL */
bitmap = ARR_NULLBITMAP(arr);
if (bitmap)
{
int bitmask = 1;
for (i = 0; i < nitems; i++)
{
if ((*bitmap & bitmask) == 0)
count++;
bitmask <<= 1;
if (bitmask == 0x100)
{
bitmap++;
bitmask = 1;
}
}
}
*nargs = nitems;
*nulls = count;
}
else
{
/* Separate arguments, so just count 'em */
for (i = 0; i < PG_NARGS(); i++)
{
if (PG_ARGISNULL(i))
count++;
}
*nargs = PG_NARGS();
*nulls = count;
}
return true;
}
/*
* num_nulls()
* Count the number of NULL arguments
*/
Datum
pg_num_nulls(PG_FUNCTION_ARGS)
{
int32 nargs,
nulls;
if (!count_nulls(fcinfo, &nargs, &nulls))
PG_RETURN_NULL();
PG_RETURN_INT32(nulls);
}
/*
* num_nonnulls()
* Count the number of non-NULL arguments
*/
Datum
pg_num_nonnulls(PG_FUNCTION_ARGS)
{
int32 nargs,
nulls;
if (!count_nulls(fcinfo, &nargs, &nulls))
PG_RETURN_NULL();
PG_RETURN_INT32(nargs - nulls);
}
/*
* current_database()
* Expose the current database to the user
*/
Datum
current_database(PG_FUNCTION_ARGS)
{
Name db;
db = (Name) palloc(NAMEDATALEN);
namestrcpy(db, get_database_name(MyDatabaseId));
PG_RETURN_NAME(db);
}
/*
* current_query()
* Expose the current query to the user (useful in stored procedures)
* We might want to use ActivePortal->sourceText someday.
*/
Datum
current_query(PG_FUNCTION_ARGS)
{
/* there is no easy way to access the more concise 'query_string' */
if (debug_query_string)
PG_RETURN_TEXT_P(cstring_to_text(debug_query_string));
else
PG_RETURN_NULL();
}
/* Function to find out which databases make use of a tablespace */
typedef struct
{
char *location;
DIR *dirdesc;
} ts_db_fctx;
Datum
pg_tablespace_databases(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
struct dirent *de;
ts_db_fctx *fctx;
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
Oid tablespaceOid = PG_GETARG_OID(0);
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
fctx = palloc(sizeof(ts_db_fctx));
if (tablespaceOid == GLOBALTABLESPACE_OID)
{
fctx->dirdesc = NULL;
ereport(WARNING,
(errmsg("global tablespace never has databases")));
}
else
{
if (tablespaceOid == DEFAULTTABLESPACE_OID)
fctx->location = psprintf("base");
else
fctx->location = psprintf("pg_tblspc/%u/%s", tablespaceOid,
GP_TABLESPACE_VERSION_DIRECTORY);
fctx->dirdesc = AllocateDir(fctx->location);
if (!fctx->dirdesc)
{
/* the only expected error is ENOENT */
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
fctx->location)));
ereport(WARNING,
(errmsg("%u is not a tablespace OID", tablespaceOid)));
}
}
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
fctx = (ts_db_fctx *) funcctx->user_fctx;
if (!fctx->dirdesc) /* not a tablespace */
SRF_RETURN_DONE(funcctx);
while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
{
Oid datOid = atooid(de->d_name);
char *subdir;
bool isempty;
/* this test skips . and .., but is awfully weak */
if (!datOid)
continue;
/* if database subdir is empty, don't report tablespace as used */
subdir = psprintf("%s/%s", fctx->location, de->d_name);
isempty = directory_is_empty(subdir);
pfree(subdir);
if (isempty)
continue; /* indeed, nothing in it */
SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(datOid));
}
FreeDir(fctx->dirdesc);
SRF_RETURN_DONE(funcctx);
}
/*
* pg_tablespace_location - get location for a tablespace
*/
Datum
pg_tablespace_location(PG_FUNCTION_ARGS)
{
Oid tablespaceOid = PG_GETARG_OID(0);
char sourcepath[MAXPGPATH];
char targetpath[MAXPGPATH];
int rllen;
/*
* It's useful to apply this function to pg_class.reltablespace, wherein
* zero means "the database's default tablespace". So, rather than
* throwing an error for zero, we choose to assume that's what is meant.
*/
if (tablespaceOid == InvalidOid)
tablespaceOid = MyDatabaseTableSpace;
/*
* Return empty string for the cluster's default tablespaces
*/
if (tablespaceOid == DEFAULTTABLESPACE_OID ||
tablespaceOid == GLOBALTABLESPACE_OID)
PG_RETURN_TEXT_P(cstring_to_text(""));
#if defined(HAVE_READLINK) || defined(WIN32)
/*
* Find the location of the tablespace by reading the symbolic link that
* is in pg_tblspc/<oid>.
*/
snprintf(sourcepath, sizeof(sourcepath), "pg_tblspc/%u", tablespaceOid);
rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
if (rllen < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read symbolic link \"%s\": %m",
sourcepath)));
if (rllen >= sizeof(targetpath))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("symbolic link \"%s\" target is too long",
sourcepath)));
targetpath[rllen] = '\0';
get_parent_directory(targetpath);
if (strcmp(targetpath, "") == 0)
ereport(ERROR,
(errmsg("path to tablespace is not a valid path: \"%s\"",
sourcepath)));
PG_RETURN_TEXT_P(cstring_to_text(targetpath));
#else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablespaces are not supported on this platform")));
PG_RETURN_NULL();
#endif
}
/*
* pg_sleep - delay for N seconds
*/
Datum
pg_sleep(PG_FUNCTION_ARGS)
{
float8 secs = PG_GETARG_FLOAT8(0);
float8 endtime;
/*
* We sleep using WaitLatch, to ensure that we'll wake up promptly if an
* important signal (such as SIGALRM or SIGINT) arrives. Because
* WaitLatch's upper limit of delay is INT_MAX milliseconds, and the user
* might ask for more than that, we sleep for at most 10 minutes and then
* loop.
*
* By computing the intended stop time initially, we avoid accumulation of
* extra delay across multiple sleeps. This also ensures we won't delay
* less than the specified time when WaitLatch is terminated early by a
* non-query-canceling signal such as SIGHUP.
*/
#define GetNowFloat() ((float8) GetCurrentTimestamp() / 1000000.0)
endtime = GetNowFloat() + secs;
for (;;)
{
float8 delay;
long delay_ms;
CHECK_FOR_INTERRUPTS();
delay = endtime - GetNowFloat();
if (delay >= 600.0)
delay_ms = 600000;
else if (delay > 0.0)
delay_ms = (long) ceil(delay * 1000.0);
else
break;
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
delay_ms,
WAIT_EVENT_PG_SLEEP);
ResetLatch(MyLatch);
}
PG_RETURN_VOID();
}
/* Function to return the list of grammar keywords */
Datum
pg_get_keywords(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
TupleDesc tupdesc;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
tupdesc = CreateTemplateTupleDesc(3);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "word",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "catcode",
CHAROID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "catdesc",
TEXTOID, -1, 0);
funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
if (funcctx->call_cntr < ScanKeywords.num_keywords)
{
char *values[3];
HeapTuple tuple;
/* cast-away-const is ugly but alternatives aren't much better */
values[0] = unconstify(char *,
GetScanKeyword(funcctx->call_cntr,
&ScanKeywords));
switch (ScanKeywordCategories[funcctx->call_cntr])
{
case UNRESERVED_KEYWORD:
values[1] = "U";
values[2] = _("unreserved");
break;
case COL_NAME_KEYWORD:
values[1] = "C";
values[2] = _("unreserved (cannot be function or type name)");
break;
case TYPE_FUNC_NAME_KEYWORD:
values[1] = "T";
values[2] = _("reserved (can be function or type name)");
break;
case RESERVED_KEYWORD:
values[1] = "R";
values[2] = _("reserved");
break;
default: /* shouldn't be possible */
values[1] = NULL;
values[2] = NULL;
break;
}
tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
}
SRF_RETURN_DONE(funcctx);
}
/*
* Return the type of the argument.
*/
Datum
pg_typeof(PG_FUNCTION_ARGS)
{
PG_RETURN_OID(get_fn_expr_argtype(fcinfo->flinfo, 0));
}
/*
* Implementation of the COLLATE FOR expression; returns the collation
* of the argument.
*/
Datum
pg_collation_for(PG_FUNCTION_ARGS)
{
Oid typeid;
Oid collid;
typeid = get_fn_expr_argtype(fcinfo->flinfo, 0);
if (!typeid)
PG_RETURN_NULL();
if (!type_is_collatable(typeid) && typeid != UNKNOWNOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("collations are not supported by type %s",
format_type_be(typeid))));
collid = PG_GET_COLLATION();
if (!collid)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text(generate_collation_name(collid)));
}
/*
* pg_relation_is_updatable - determine which update events the specified
* relation supports.
*
* This relies on relation_is_updatable() in rewriteHandler.c, which see
* for additional information.
*/
Datum
pg_relation_is_updatable(PG_FUNCTION_ARGS)
{
Oid reloid = PG_GETARG_OID(0);
bool include_triggers = PG_GETARG_BOOL(1);
PG_RETURN_INT32(relation_is_updatable(reloid, include_triggers, NULL));
}
/*
* pg_column_is_updatable - determine whether a column is updatable
*
* This function encapsulates the decision about just what
* information_schema.columns.is_updatable actually means. It's not clear
* whether deletability of the column's relation should be required, so
* we want that decision in C code where we could change it without initdb.
*/
Datum
pg_column_is_updatable(PG_FUNCTION_ARGS)
{
Oid reloid = PG_GETARG_OID(0);
AttrNumber attnum = PG_GETARG_INT16(1);
AttrNumber col = attnum - FirstLowInvalidHeapAttributeNumber;
bool include_triggers = PG_GETARG_BOOL(2);
int events;
/* System columns are never updatable */
if (attnum <= 0)
PG_RETURN_BOOL(false);
events = relation_is_updatable(reloid, include_triggers,
bms_make_singleton(col));
/* We require both updatability and deletability of the relation */
#define REQ_EVENTS ((1 << CMD_UPDATE) | (1 << CMD_DELETE))
PG_RETURN_BOOL((events & REQ_EVENTS) == REQ_EVENTS);
}
/*
* Is character a valid identifier start?
* Must match scan.l's {ident_start} character class.
*/
static bool
is_ident_start(unsigned char c)
{
/* Underscores and ASCII letters are OK */
if (c == '_')
return true;
if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
return true;
/* Any high-bit-set character is OK (might be part of a multibyte char) */
if (IS_HIGHBIT_SET(c))
return true;
return false;
}
/*
* Is character a valid identifier continuation?
* Must match scan.l's {ident_cont} character class.
*/
static bool
is_ident_cont(unsigned char c)
{
/* Can be digit or dollar sign ... */
if ((c >= '0' && c <= '9') || c == '$')
return true;
/* ... or an identifier start character */
return is_ident_start(c);
}
/*
* parse_ident - parse a SQL qualified identifier into separate identifiers.
* When strict mode is active (second parameter), then any chars after
* the last identifier are disallowed.
*/
Datum
parse_ident(PG_FUNCTION_ARGS)
{
text *qualname = PG_GETARG_TEXT_PP(0);
bool strict = PG_GETARG_BOOL(1);
char *qualname_str = text_to_cstring(qualname);
ArrayBuildState *astate = NULL;
char *nextp;
bool after_dot = false;
/*
* The code below scribbles on qualname_str in some cases, so we should
* reconvert qualname if we need to show the original string in error
* messages.
*/
nextp = qualname_str;
/* skip leading whitespace */
while (scanner_isspace(*nextp))
nextp++;
for (;;)
{
char *curname;
bool missing_ident = true;
if (*nextp == '"')
{
char *endp;
curname = nextp + 1;
for (;;)
{
endp = strchr(nextp + 1, '"');
if (endp == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname)),
errdetail("String has unclosed double quotes.")));
if (endp[1] != '"')
break;
memmove(endp, endp + 1, strlen(endp));
nextp = endp;
}
nextp = endp + 1;
*endp = '\0';
if (endp - curname == 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname)),
errdetail("Quoted identifier must not be empty.")));
astate = accumArrayResult(astate, CStringGetTextDatum(curname),
false, TEXTOID, CurrentMemoryContext);
missing_ident = false;
}
else if (is_ident_start((unsigned char) *nextp))
{
char *downname;
int len;
text *part;
curname = nextp++;
while (is_ident_cont((unsigned char) *nextp))
nextp++;
len = nextp - curname;
/*
* We don't implicitly truncate identifiers. This is useful for
* allowing the user to check for specific parts of the identifier
* being too long. It's easy enough for the user to get the
* truncated names by casting our output to name[].
*/
downname = downcase_identifier(curname, len, false, false);
part = cstring_to_text_with_len(downname, len);
astate = accumArrayResult(astate, PointerGetDatum(part), false,
TEXTOID, CurrentMemoryContext);
missing_ident = false;
}
if (missing_ident)
{
/* Different error messages based on where we failed. */
if (*nextp == '.')
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname)),
errdetail("No valid identifier before \".\".")));
else if (after_dot)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname)),
errdetail("No valid identifier after \".\".")));
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname))));
}
while (scanner_isspace(*nextp))
nextp++;
if (*nextp == '.')
{
after_dot = true;
nextp++;
while (scanner_isspace(*nextp))
nextp++;
}
else if (*nextp == '\0')
{
break;
}
else
{
if (strict)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("string is not a valid identifier: \"%s\"",
text_to_cstring(qualname))));
break;
}
}
PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
}
/*
* pg_current_logfile
*
* Report current log file used by log collector by scanning current_logfiles.
*/
Datum
pg_current_logfile(PG_FUNCTION_ARGS)
{
FILE *fd;
char lbuffer[MAXPGPATH];
char *logfmt;
char *log_filepath;
char *log_format = lbuffer;
char *nlpos;
/* The log format parameter is optional */
if (PG_NARGS() == 0 || PG_ARGISNULL(0))
logfmt = NULL;
else
{
logfmt = text_to_cstring(PG_GETARG_TEXT_PP(0));
if (strcmp(logfmt, "stderr") != 0 && strcmp(logfmt, "csvlog") != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("log format \"%s\" is not supported", logfmt),
errhint("The supported log formats are \"stderr\" and \"csvlog\".")));
}
fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
if (fd == NULL)
{
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m",
LOG_METAINFO_DATAFILE)));
PG_RETURN_NULL();
}
/*
* Read the file to gather current log filename(s) registered by the
* syslogger.
*/
while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL)
{
/*
* Extract log format and log file path from the line; lbuffer ==
* log_format, they share storage.
*/
log_filepath = strchr(lbuffer, ' ');
if (log_filepath == NULL)
{
/* Uh oh. No space found, so file content is corrupted. */
elog(ERROR,
"missing space character in \"%s\"", LOG_METAINFO_DATAFILE);
break;
}
*log_filepath = '\0';
log_filepath++;
nlpos = strchr(log_filepath, '\n');
if (nlpos == NULL)
{
/* Uh oh. No newline found, so file content is corrupted. */
elog(ERROR,
"missing newline character in \"%s\"", LOG_METAINFO_DATAFILE);
break;
}
*nlpos = '\0';
if (logfmt == NULL || strcmp(logfmt, log_format) == 0)
{
FreeFile(fd);
PG_RETURN_TEXT_P(cstring_to_text(log_filepath));
}
}
/* Close the current log filename file. */
FreeFile(fd);
PG_RETURN_NULL();
}
/*
* Report current log file used by log collector (1 argument version)
*
* note: this wrapper is necessary to pass the sanity check in opr_sanity,
* which checks that all built-in functions that share the implementing C
* function take the same number of arguments
*/
Datum
pg_current_logfile_1arg(PG_FUNCTION_ARGS)
{
return pg_current_logfile(fcinfo);
}
/*
* SQL wrapper around RelationGetReplicaIndex().
*/
Datum
pg_get_replica_identity_index(PG_FUNCTION_ARGS)
{
Oid reloid = PG_GETARG_OID(0);
Oid idxoid;
Relation rel;
rel = table_open(reloid, AccessShareLock);
idxoid = RelationGetReplicaIndex(rel);
table_close(rel, AccessShareLock);
if (OidIsValid(idxoid))
PG_RETURN_OID(idxoid);
else
PG_RETURN_NULL();
}
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