greenplumn external 源码
greenplumn external 代码
文件路径：/src/backend/access/external/external.c
/*-------------------------------------------------------------------------
*
* external.c
* routines for getting external info from external table fdw.
*
* Portions Copyright (c) 2020-Present VMware, Inc. or its affiliates.
*
* IDENTIFICATION
* src/backend/access/external/external.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <fstream/gfile.h>
#include "access/external.h"
#include "access/reloptions.h"
#include "access/table.h"
#include "catalog/indexing.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_foreign_table.h"
#include "cdb/cdbsreh.h"
#include "cdb/cdbvars.h"
#include "commands/defrem.h"
#include "foreign/foreign.h"
#include "mb/pg_wchar.h"
#include "nodes/makefuncs.h"
#include "optimizer/optimizer.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/uri.h"
static List *create_external_scan_uri_list(ExtTableEntry *ext, bool *ismasteronly);
void
gfile_printf_then_putc_newline(const char *format,...)
{
char *a;
va_list va;
int i;
va_start(va, format);
i = vsnprintf(0, 0, format, va);
va_end(va);
if (i < 0)
elog(NOTICE, "gfile_printf_then_putc_newline vsnprintf failed.");
else if (!(a = palloc(i + 1)))
elog(NOTICE, "gfile_printf_then_putc_newline palloc failed.");
else
{
va_start(va, format);
vsnprintf(a, i + 1, format, va);
va_end(va);
elog(NOTICE, "%s", a);
pfree(a);
}
}
void *
gfile_malloc(size_t size)
{
return palloc(size);
}
void
gfile_free(void *a)
{
pfree(a);
}
/* transform the locations string to a list */
List*
TokenizeLocationUris(char *uris)
{
char *uri = NULL;
List *result = NIL;
Assert(uris != NULL);
while ((uri = strsep(&uris, "|")) != NULL)
{
result = lappend(result, makeString(uri));
}
return result;
}
/*
* Get the entry for an exttable relation (from pg_foreign_table)
*/
ExtTableEntry*
GetExtTableEntry(Oid relid)
{
ExtTableEntry *extentry;
extentry = GetExtTableEntryIfExists(relid);
if (!extentry)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("missing pg_foreign_table entry for relation \"%s\"",
get_rel_name(relid))));
return extentry;
}
/*
* Like GetExtTableEntry(Oid), but returns NULL instead of throwing
* an error if no pg_foreign_table entry is found.
*/
ExtTableEntry*
GetExtTableEntryIfExists(Oid relid)
{
Relation pg_foreign_table_rel;
ScanKeyData ftkey;
SysScanDesc ftscan;
HeapTuple fttuple;
ExtTableEntry *extentry;
bool isNull;
List *ftoptions_list = NIL;;
pg_foreign_table_rel = table_open(ForeignTableRelationId, RowExclusiveLock);
ScanKeyInit(&ftkey,
Anum_pg_foreign_table_ftrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
ftscan = systable_beginscan(pg_foreign_table_rel, ForeignTableRelidIndexId,
true, NULL, 1, &ftkey);
fttuple = systable_getnext(ftscan);
if (!HeapTupleIsValid(fttuple))
{
systable_endscan(ftscan);
heap_close(pg_foreign_table_rel, RowExclusiveLock);
return NULL;
}
/* get the foreign table options */
Datum ftoptions = heap_getattr(fttuple,
Anum_pg_foreign_table_ftoptions,
RelationGetDescr(pg_foreign_table_rel),
&isNull);
if (isNull)
{
/* options array is always populated, {} if no options set */
elog(ERROR, "could not find options for external protocol");
}
else
{
ftoptions_list = untransformRelOptions(ftoptions);
}
extentry = GetExtFromForeignTableOptions(ftoptions_list, relid);
/* Finish up scan and close catalogs */
systable_endscan(ftscan);
table_close(pg_foreign_table_rel, RowExclusiveLock);
return extentry;
}
ExtTableEntry *
GetExtFromForeignTableOptions(List *ftoptons, Oid relid)
{
ExtTableEntry *extentry;
ListCell *lc;
List *entryOptions = NIL;
char *arg;
bool fmtcode_found = false;
bool rejectlimit_found = false;
bool rejectlimittype_found = false;
bool logerrors_found = false;
bool encoding_found = false;
bool iswritable_found = false;
bool locationuris_found = false;
bool command_found = false;
extentry = (ExtTableEntry *) palloc0(sizeof(ExtTableEntry));
foreach(lc, ftoptons)
{
DefElem *def = (DefElem *) lfirst(lc);
if (pg_strcasecmp(def->defname, "location_uris") == 0)
{
extentry->urilocations = TokenizeLocationUris(defGetString(def));
locationuris_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "execute_on") == 0)
{
extentry->execlocations = list_make1(makeString(defGetString(def)));
continue;
}
if (pg_strcasecmp(def->defname, "command") == 0)
{
extentry->command = defGetString(def);
command_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "format_type") == 0)
{
arg = defGetString(def);
extentry->fmtcode = arg[0];
fmtcode_found = true;
continue;
}
/* only CSV format needs this for ProcessCopyOptions(), will do it later */
if (pg_strcasecmp(def->defname, "format") == 0)
{
continue;
}
if (pg_strcasecmp(def->defname, "reject_limit") == 0)
{
extentry->rejectlimit = atoi(defGetString(def));
rejectlimit_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "reject_limit_type") == 0)
{
arg = defGetString(def);
extentry->rejectlimittype = arg[0];
rejectlimittype_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "log_errors") == 0)
{
arg = defGetString(def);
extentry->logerrors = arg[0];
logerrors_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "encoding") == 0)
{
extentry->encoding = atoi(defGetString(def));
encoding_found = true;
continue;
}
if (pg_strcasecmp(def->defname, "is_writable") == 0)
{
extentry->iswritable = defGetBoolean(def);
iswritable_found = true;
continue;
}
entryOptions = lappend(entryOptions, makeDefElem(def->defname, (Node *) makeString(pstrdup(defGetString(def))), -1));
}
/* If CSV format was chosen, make it visible to ProcessCopyOptions. */
if (fmttype_is_csv(extentry->fmtcode))
entryOptions = lappend(entryOptions, makeDefElem("format", (Node *) makeString("csv"), -1));
/*
* external table syntax does have these for sure, but errors could happen
* if using foreign table syntax
*/
if (!fmtcode_found || !logerrors_found || !encoding_found || !iswritable_found)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("missing format, logerrors, encoding or iswritable options for relation \"%s\"",
get_rel_name(relid))));
if (locationuris_found && command_found)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("locationuris and command options conflict with each other")));
if (!fmttype_is_custom(extentry->fmtcode) &&
!fmttype_is_csv(extentry->fmtcode) &&
!fmttype_is_text(extentry->fmtcode))
elog(ERROR, "unsupported format type %d for external table", extentry->fmtcode);
if (!rejectlimit_found) {
/* mark that no SREH requested */
extentry->rejectlimit = -1;
}
if (rejectlimittype_found)
{
if (extentry->rejectlimittype != 'r' && extentry->rejectlimittype != 'p')
elog(ERROR, "unsupported reject limit type %c for external table",
extentry->rejectlimittype);
}
else
extentry->rejectlimittype = -1;
if (!PG_VALID_ENCODING(extentry->encoding))
elog(ERROR, "invalid encoding found for external table");
extentry->options = entryOptions;
return extentry;
}
ExternalScanInfo *
MakeExternalScanInfo(ExtTableEntry *extEntry)
{
ExternalScanInfo *node = makeNode(ExternalScanInfo);
List *urilist;
bool ismasteronly = false;
bool islimitinrows = false;
int rejectlimit = -1;
char logerrors = LOG_ERRORS_DISABLE;
static uint32 scancounter = 0;
if (extEntry->rejectlimit != -1)
{
/*
* single row error handling is requested, make sure reject limit and
* reject type are valid.
*
* NOTE: this should never happen unless somebody modified the catalog
* manually. We are just being pedantic here.
*/
VerifyRejectLimit(extEntry->rejectlimittype, extEntry->rejectlimit);
}
/* assign Uris to segments. */
urilist = create_external_scan_uri_list(extEntry, &ismasteronly);
/* single row error handling */
if (extEntry->rejectlimit != -1)
{
islimitinrows = (extEntry->rejectlimittype == 'r' ? true : false);
rejectlimit = extEntry->rejectlimit;
logerrors = extEntry->logerrors;
}
node->uriList = urilist;
node->fmtType = extEntry->fmtcode;
node->isMasterOnly = ismasteronly;
node->rejLimit = rejectlimit;
node->rejLimitInRows = islimitinrows;
node->logErrors = logerrors;
node->encoding = extEntry->encoding;
node->scancounter = scancounter++;
node->extOptions = extEntry->options;
return node;
}
/*
* entry point from ORCA, to create a ForeignScan plan for an external table.
*
* Note: the caller is responsible for filling the cost information.
*/
ForeignScan *
BuildForeignScanForExternalTable(Oid relid, Index scanrelid,
List *qual, List *targetlist)
{
ExtTableEntry *extEntry;
ForeignScan *fscan;
ExternalScanInfo *externalscan_info;
extEntry = GetExtTableEntry(relid);
externalscan_info = MakeExternalScanInfo(extEntry);
fscan = makeNode(ForeignScan);
fscan->scan.scanrelid = scanrelid;
fscan->scan.plan.qual = qual;
fscan->scan.plan.targetlist = targetlist;
/* cost will be filled in by create_foreignscan_plan */
fscan->operation = CMD_SELECT;
/* fs_server will be filled in by create_foreignscan_plan */
fscan->fs_server = get_foreign_server_oid(GP_EXTTABLE_SERVER_NAME, false);
fscan->fdw_exprs = NIL;
fscan->fdw_private = list_make1(externalscan_info);
fscan->fdw_scan_tlist = NIL;
fscan->fdw_recheck_quals = NIL;
fscan->fs_relids = bms_make_singleton(scanrelid);
/*
* Like in create_foreign_plan(), if rel is a base relation, detect
* whether any system columns are requested from the rel.
*/
fscan->fsSystemCol = false;
if (scanrelid > 0)
{
Bitmapset *attrs_used = NULL;
int i;
/*
* First, examine all the attributes needed for joins or final output.
* Note: we must look at rel's targetlist, not the attr_needed data,
* because attr_needed isn't computed for inheritance child rels.
*/
pull_varattnos((Node *) targetlist, scanrelid, &attrs_used);
/* Now, are any system columns requested from rel? */
for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
{
if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used))
{
fscan->fsSystemCol = true;
break;
}
}
bms_free(attrs_used);
}
return fscan;
}
static List *
create_external_scan_uri_list(ExtTableEntry *ext, bool *ismasteronly)
{
ListCell *c;
List *modifiedloclist = NIL;
int i;
CdbComponentDatabases *db_info;
int total_primaries;
char **segdb_file_map;
/* various processing flags */
bool using_execute = false; /* true if EXECUTE is used */
bool using_location; /* true if LOCATION is used */
bool found_candidate = false;
bool found_match = false;
bool done = false;
List *filenames;
/* gpfdist(s) or EXECUTE specific variables */
int total_to_skip = 0;
int max_participants_allowed = 0;
int num_segs_participating = 0;
bool *skip_map = NULL;
bool should_skip_randomly = false;
Uri *uri;
char *on_clause;
*ismasteronly = false;
/* is this an EXECUTE table or a LOCATION (URI) table */
if (ext->command)
{
using_execute = true;
using_location = false;
}
else
{
using_execute = false;
using_location = true;
}
/* is this an EXECUTE table or a LOCATION (URI) table */
if (ext->command && !gp_external_enable_exec)
{
ereport(ERROR,
(errcode(ERRCODE_GP_FEATURE_NOT_CONFIGURED), /* any better errcode? */
errmsg("using external tables with OS level commands (EXECUTE clause) is disabled"),
errhint("To enable set gp_external_enable_exec=on.")));
}
/* various validations */
if (ext->iswritable)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot read from a WRITABLE external table"),
errhint("Create the table as READABLE instead.")));
/*
* take a peek at the first URI so we know which protocol we'll deal with
*/
if (!using_execute)
{
char *first_uri_str;
first_uri_str = strVal(linitial(ext->urilocations));
uri = ParseExternalTableUri(first_uri_str);
}
else
uri = NULL;
/* get the ON clause information, and restrict 'ON COORDINATOR' to custom
* protocols only */
on_clause = (char *) strVal(linitial(ext->execlocations));
if ((strcmp(on_clause, "COORDINATOR_ONLY") == 0)
&& using_location && (uri->protocol != URI_CUSTOM)) {
ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("\'ON COORDINATOR\' is not supported by this protocol yet")));
}
/* get the total valid primary segdb count */
db_info = cdbcomponent_getCdbComponents();
total_primaries = 0;
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
total_primaries++;
}
/*
* initialize a file-to-segdb mapping. segdb_file_map string array indexes
* segindex and the entries are the external file path is assigned to this
* segment database. For example if segdb_file_map[2] has "/tmp/emp.1" then
* this file is assigned to primary segdb 2. if an entry has NULL then
* that segdb isn't assigned any file.
*/
segdb_file_map = (char **) palloc0(total_primaries * sizeof(char *));
/*
* Now we do the actual assignment of work to the segment databases (where
* work is either a URI to open or a command to execute). Due to the big
* differences between the different protocols we handle each one
* separately. Unfortunately this means some code duplication, but keeping
* this separation makes the code much more understandable and (even) more
* maintainable.
*
* Outline of the following code blocks (from simplest to most complex):
* (only one of these will get executed for a statement)
*
* 1) segment mapping for tables with LOCATION http:// or file:// .
*
* These two protocols are very similar in that they enforce a
* 1-URI:1-segdb relationship. The only difference between them is that
* file:// URI must be assigned to a segdb on a host that is local to that
* URI.
*
* 2) segment mapping for tables with LOCATION gpfdist(s):// or custom
* protocol
*
* This protocol is more complicated - in here we usually duplicate the
* user supplied gpfdist(s):// URIs until there is one available to every
* segdb. However, in some cases (as determined by gp_external_max_segs
* GUC) we don't want to use *all* segdbs but instead figure out how many
* and pick them randomly (this is mainly for better performance and
* resource mgmt).
*
* 3) segment mapping for tables with EXECUTE 'cmd' ON.
*
* In here we don't have URI's. We have a single command string and a
* specification of the segdb granularity it should get executed on (the
* ON clause). Depending on the ON clause specification we could go many
* different ways, for example: assign the command to all segdb, or one
* command per host, or assign to 5 random segments, etc...
*/
/* (1) */
if (using_location && (uri->protocol == URI_FILE || uri->protocol == URI_HTTP))
{
/*
* extract file path and name from URI strings and assign them a
* primary segdb
*/
foreach(c, ext->urilocations)
{
const char *uri_str = (char *) strVal(lfirst(c));
uri = ParseExternalTableUri(uri_str);
found_candidate = false;
found_match = false;
/*
* look through our segment database list and try to find a
* database that can handle this uri.
*/
for (i = 0; i < db_info->total_segment_dbs && !found_match; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
/*
* Assign mapping of external file to this segdb only if:
* 1) This segdb is a valid primary.
* 2) An external file wasn't already assigned to it.
* 3) If 'file' protocol, host of segdb and file must be
* the same.
*
* This logic also guarantees that file that appears first in
* the external location list for the same host gets assigned
* the segdb with the lowest index for this host.
*/
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
{
if (uri->protocol == URI_FILE)
{
if (pg_strcasecmp(uri->hostname, p->config->hostname) != 0 && pg_strcasecmp(uri->hostname, p->config->address) != 0)
continue;
}
/* a valid primary segdb exist on this host */
found_candidate = true;
if (segdb_file_map[segind] == NULL)
{
/* segdb not taken yet. assign this URI to this segdb */
segdb_file_map[segind] = pstrdup(uri_str);
found_match = true;
}
/*
* too bad. this segdb already has an external source
* assigned
*/
}
}
/*
* We failed to find a segdb for this URI.
*/
if (!found_match)
{
if (uri->protocol == URI_FILE)
{
if (found_candidate)
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("could not assign a segment database for \"%s\"",
uri_str),
errdetail("There are more external files than primary segment databases on host \"%s\"",
uri->hostname)));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("could not assign a segment database for \"%s\"",
uri_str),
errdetail("There isn't a valid primary segment database on host \"%s\"",
uri->hostname)));
}
}
else /* HTTP */
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("could not assign a segment database for \"%s\"",
uri_str),
errdetail("There are more URIs than total primary segment databases")));
}
}
}
}
/* (2) */
else if (using_location && (uri->protocol == URI_GPFDIST ||
uri->protocol == URI_GPFDISTS ||
uri->protocol == URI_CUSTOM))
{
if ((strcmp(on_clause, "COORDINATOR_ONLY") == 0) && (uri->protocol == URI_CUSTOM))
{
const char *uri_str = strVal(linitial(ext->urilocations));
segdb_file_map[0] = pstrdup(uri_str);
*ismasteronly = true;
}
else
{
/*
* Re-write the location list for GPFDIST or GPFDISTS before mapping to segments.
*
* If we happen to be dealing with URI's with the 'gpfdist' (or 'gpfdists') protocol
* we do an extra step here.
*
* (*) We modify the urilocationlist so that every
* primary segdb will get a URI (therefore we duplicate the existing
* URI's until the list is of size = total_primaries).
* Example: 2 URIs, 7 total segdbs.
* Original LocationList: URI1->URI2
* Modified LocationList: URI1->URI2->URI1->URI2->URI1->URI2->URI1
*
* (**) We also make sure that we don't allocate more segdbs than
* (# of URIs x gp_external_max_segs).
* Example: 2 URIs, 7 total segdbs, gp_external_max_segs = 3
* Original LocationList: URI1->URI2
* Modified LocationList: URI1->URI2->URI1->URI2->URI1->URI2 (6 total).
*
* (***) In that case that we need to allocate only a subset of primary
* segdbs and not all we then also create a random map of segments to skip.
* Using the previous example a we create a map of 7 entries and need to
* randomly select 1 segdb to skip (7 - 6 = 1). so it may look like this:
* [F F T F F F F] - in which case we know to skip the 3rd segment only.
*/
/* total num of segs that will participate in the external operation */
num_segs_participating = total_primaries;
/* max num of segs that are allowed to participate in the operation */
if ((uri->protocol == URI_GPFDIST) || (uri->protocol == URI_GPFDISTS))
{
max_participants_allowed = list_length(ext->urilocations) *
gp_external_max_segs;
}
else
{
/*
* for custom protocol, set max_participants_allowed to
* num_segs_participating so that assignment to segments will use
* all available segments
*/
max_participants_allowed = num_segs_participating;
}
elog(DEBUG5,
"num_segs_participating = %d. max_participants_allowed = %d. number of URIs = %d",
num_segs_participating, max_participants_allowed, list_length(ext->urilocations));
/* see (**) above */
if (num_segs_participating > max_participants_allowed)
{
total_to_skip = num_segs_participating - max_participants_allowed;
num_segs_participating = max_participants_allowed;
should_skip_randomly = true;
elog(NOTICE, "External scan %s will utilize %d out "
"of %d segment databases",
(uri->protocol == URI_GPFDIST ? "from gpfdist(s) server" : "using custom protocol"),
num_segs_participating,
total_primaries);
}
if (list_length(ext->urilocations) > num_segs_participating)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("there are more external files (URLs) than primary segments that can read them"),
errdetail("Found %d URLs and %d primary segments.",
list_length(ext->urilocations),
num_segs_participating)));
/*
* restart location list and fill in new list until number of
* locations equals the number of segments participating in this
* action (see (*) above for more details).
*/
while (!done)
{
foreach(c, ext->urilocations)
{
char *uri_str = (char *) strVal(lfirst(c));
/* append to a list of Value nodes, size nelems */
modifiedloclist = lappend(modifiedloclist, makeString(pstrdup(uri_str)));
if (list_length(modifiedloclist) == num_segs_participating)
{
done = true;
break;
}
if (list_length(modifiedloclist) > num_segs_participating)
{
elog(ERROR, "External scan location list failed building distribution.");
}
}
}
/* See (***) above for details */
if (should_skip_randomly)
skip_map = makeRandomSegMap(total_primaries, total_to_skip);
/*
* assign each URI from the new location list a primary segdb
*/
foreach(c, modifiedloclist)
{
const char *uri_str = strVal(lfirst(c));
uri = ParseExternalTableUri(uri_str);
found_match = false;
/*
* look through our segment database list and try to find a
* database that can handle this uri.
*/
for (i = 0; i < db_info->total_segment_dbs && !found_match; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
/*
* Assign mapping of external file to this segdb only if:
* 1) This segdb is a valid primary.
* 2) An external file wasn't already assigned to it.
*/
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
{
/*
* skip this segdb if skip_map for this seg index tells us
* to skip it (set to 'true').
*/
if (should_skip_randomly)
{
Assert(segind < total_primaries);
if (skip_map[segind])
continue; /* skip it */
}
if (segdb_file_map[segind] == NULL)
{
/* segdb not taken yet. assign this URI to this segdb */
segdb_file_map[segind] = pstrdup(uri_str);
found_match = true;
}
/*
* too bad. this segdb already has an external source
* assigned
*/
}
}
/* We failed to find a segdb for this gpfdist(s) URI */
if (!found_match)
{
/* should never happen */
elog(LOG,
"external tables gpfdist(s) allocation error. "
"total_primaries: %d, num_segs_participating %d "
"max_participants_allowed %d, total_to_skip %d",
total_primaries, num_segs_participating,
max_participants_allowed, total_to_skip);
elog(ERROR,
"internal error in createplan for external tables when trying to assign segments for gpfdist(s)");
}
}
}
}
/* (3) */
else if (using_execute)
{
const char *command = ext->command;
const char *prefix = "execute:";
char *prefixed_command;
/* build the command string for the executor - 'execute:command' */
StringInfo buf = makeStringInfo();
appendStringInfo(buf, "%s%s", prefix, command);
prefixed_command = pstrdup(buf->data);
pfree(buf->data);
pfree(buf);
buf = NULL;
/*
* Now we handle each one of the ON locations separately:
*
* 1) all segs
* 2) one per host
* 3) all segs on host <foo>
* 4) seg <n> only
* 5) <n> random segs
* 6) master only
*/
if (strcmp(on_clause, "ALL_SEGMENTS") == 0)
{
/* all segments get a copy of the command to execute */
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
segdb_file_map[segind] = pstrdup(prefixed_command);
}
}
else if (strcmp(on_clause, "PER_HOST") == 0)
{
/* 1 seg per host */
List *visited_hosts = NIL;
ListCell *lc;
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
{
bool host_taken = false;
foreach(lc, visited_hosts)
{
const char *hostname = strVal(lfirst(lc));
if (pg_strcasecmp(hostname, p->config->hostname) == 0)
{
host_taken = true;
break;
}
}
/*
* if not assigned to a seg on this host before - do it
* now and add this hostname to the list so that we don't
* use segs on this host again.
*/
if (!host_taken)
{
segdb_file_map[segind] = pstrdup(prefixed_command);
visited_hosts = lappend(visited_hosts,
makeString(pstrdup(p->config->hostname)));
}
}
}
}
else if (strncmp(on_clause, "HOST:", strlen("HOST:")) == 0)
{
/* all segs on the specified host get copy of the command */
char *hostname = on_clause + strlen("HOST:");
bool match_found = false;
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
if (SEGMENT_IS_ACTIVE_PRIMARY(p) &&
pg_strcasecmp(hostname, p->config->hostname) == 0)
{
segdb_file_map[segind] = pstrdup(prefixed_command);
match_found = true;
}
}
if (!match_found)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("could not assign a segment database for command \"%s\")",
command),
errdetail("No valid primary segment was found in the requested host name \"%s\".",
hostname)));
}
else if (strncmp(on_clause, "SEGMENT_ID:", strlen("SEGMENT_ID:")) == 0)
{
/* 1 seg with specified id gets a copy of the command */
int target_segid = atoi(on_clause + strlen("SEGMENT_ID:"));
bool match_found = false;
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
if (SEGMENT_IS_ACTIVE_PRIMARY(p) && segind == target_segid)
{
segdb_file_map[segind] = pstrdup(prefixed_command);
match_found = true;
}
}
if (!match_found)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("could not assign a segment database for command \"%s\"",
command),
errdetail("The requested segment id %d is not a valid primary segment or doesn't exist in the database",
target_segid)));
}
else if (strncmp(on_clause, "TOTAL_SEGS:", strlen("TOTAL_SEGS:")) == 0)
{
/* total n segments selected randomly */
int num_segs_to_use = atoi(on_clause + strlen("TOTAL_SEGS:"));
if (num_segs_to_use > total_primaries)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("table defined with EXECUTE ON %d but there are only %d valid primary segments in the database",
num_segs_to_use, total_primaries)));
total_to_skip = total_primaries - num_segs_to_use;
skip_map = makeRandomSegMap(total_primaries, total_to_skip);
for (i = 0; i < db_info->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *p = &db_info->segment_db_info[i];
int segind = p->config->segindex;
if (SEGMENT_IS_ACTIVE_PRIMARY(p))
{
Assert(segind < total_primaries);
if (skip_map[segind])
continue; /* skip it */
segdb_file_map[segind] = pstrdup(prefixed_command);
}
}
}
else if (strcmp(on_clause, "COORDINATOR_ONLY") == 0)
{
/*
* store the command in first array entry and indicate that it is
* meant for the master segment (not seg o).
*/
segdb_file_map[0] = pstrdup(prefixed_command);
*ismasteronly = true;
}
else
{
elog(ERROR, "Internal error in createplan for external tables: got invalid ON clause code %s",
on_clause);
}
}
else
{
/* should never get here */
elog(ERROR, "Internal error in createplan for external tables");
}
/*
* convert array map to a list so it can be serialized as part of the plan
*/
filenames = NIL;
for (i = 0; i < total_primaries; i++)
{
if (segdb_file_map[i] != NULL)
filenames = lappend(filenames, makeString(segdb_file_map[i]));
else
{
/* no file for this segdb. add a null entry */
Value *n = makeNode(Value);
n->type = T_Null;
filenames = lappend(filenames, n);
}
}
return filenames;
}
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