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cstore_fdw.c
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/*-------------------------------------------------------------------------
*
* cstore_fdw.c
*
* This file contains the function definitions for scanning, analyzing, and
* copying into cstore_fdw foreign tables. Note that this file uses the API
* provided by cstore_reader and cstore_writer for reading and writing cstore
* files.
*
* Copyright (c) 2014, Citus Data, Inc.
*
* $Id$
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "cstore_fdw.h"
#include <sys/stat.h>
#include <unistd.h>
#include <limits.h>
#include "access/htup_details.h"
#include "access/reloptions.h"
#include "access/sysattr.h"
#include "catalog/namespace.h"
#include "catalog/pg_foreign_table.h"
#include "commands/copy.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
#include "commands/explain.h"
#include "commands/vacuum.h"
#include "foreign/fdwapi.h"
#include "foreign/foreign.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/var.h"
#include "tcop/utility.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
/* local functions forward declarations */
static void CStoreProcessUtility(Node *parseTree, const char *queryString,
ProcessUtilityContext context,
ParamListInfo paramListInfo,
DestReceiver *destReceiver, char *completionTag);
static bool CStoreTable(Oid relationId);
static uint64 CopyIntoCStoreTable(const CopyStmt *copyStatement,
const char *queryString);
static void CreateCStoreDatabaseDirectory(Oid databaseOid);
static bool DirectoryExists(StringInfo directoryName);
static void CreateDirectory(StringInfo directoryName);
static void DeleteCStoreTableFiles(char *filename);
static StringInfo OptionNamesString(Oid currentContextId);
static CStoreFdwOptions * CStoreGetOptions(Oid foreignTableId);
static char * CStoreGetOptionValue(Oid foreignTableId, const char *optionName);
static void ValidateForeignTableOptions(char *filename, char *compressionTypeString,
char *stripeRowCountString,
char *blockRowCountString);
static char * CStoreDefaultFilePath(Oid foreignTableId);
static CompressionType ParseCompressionType(const char *compressionTypeString);
static void CStoreGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel,
Oid foreignTableId);
static void CStoreGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel,
Oid foreignTableId);
static ForeignScan * CStoreGetForeignPlan(PlannerInfo *root, RelOptInfo *baserel,
Oid foreignTableId, ForeignPath *bestPath,
List *targetList, List *scanClauses);
static double TupleCountEstimate(RelOptInfo *baserel, const char *filename);
static BlockNumber PageCount(const char *filename);
static List * ColumnList(RelOptInfo *baserel);
static void CStoreExplainForeignScan(ForeignScanState *scanState,
ExplainState *explainState);
static void CStoreBeginForeignScan(ForeignScanState *scanState, int executorFlags);
static TupleTableSlot * CStoreIterateForeignScan(ForeignScanState *scanState);
static void CStoreEndForeignScan(ForeignScanState *scanState);
static void CStoreReScanForeignScan(ForeignScanState *scanState);
static bool CStoreAnalyzeForeignTable(Relation relation,
AcquireSampleRowsFunc *acquireSampleRowsFunc,
BlockNumber *totalPageCount);
static int CStoreAcquireSampleRows(Relation relation, int logLevel,
HeapTuple *sampleRows, int targetRowCount,
double *totalRowCount, double *totalDeadRowCount);
/* declarations for dynamic loading */
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(cstore_ddl_event_end_trigger);
PG_FUNCTION_INFO_V1(cstore_table_size);
PG_FUNCTION_INFO_V1(cstore_fdw_handler);
PG_FUNCTION_INFO_V1(cstore_fdw_validator);
/* saved hook value in case of unload */
static ProcessUtility_hook_type PreviousProcessUtilityHook = NULL;
/*
* _PG_init is called when the module is loaded. In this function we save the
* previous utility hook, and then install our hook to pre-intercept calls to
* the copy command.
*/
void _PG_init(void)
{
PreviousProcessUtilityHook = ProcessUtility_hook;
ProcessUtility_hook = CStoreProcessUtility;
}
/*
* _PG_fini is called when the module is unloaded. This function uninstalls the
* extension's hooks.
*/
void _PG_fini(void)
{
ProcessUtility_hook = PreviousProcessUtilityHook;
}
/*
* cstore_ddl_event_end_trigger is the event trigger function which is called on
* ddl_command_end event. This function creates required directories after the
* CREATE SERVER statement and valid data and footer files after the CREATE FOREIGN
* TABLE statement.
*/
Datum
cstore_ddl_event_end_trigger(PG_FUNCTION_ARGS)
{
EventTriggerData *triggerData = NULL;
Node *parseTree = NULL;
/* error if event trigger manager did not call this function */
if (!CALLED_AS_EVENT_TRIGGER(fcinfo))
{
ereport(ERROR, (errmsg("trigger not fired by event trigger manager")));
}
triggerData = (EventTriggerData *) fcinfo->context;
parseTree = triggerData->parsetree;
if (nodeTag(parseTree) == T_CreateForeignServerStmt)
{
CreateForeignServerStmt *serverStatement = (CreateForeignServerStmt *) parseTree;
char *foreignWrapperName = serverStatement->fdwname;
if (strncmp(foreignWrapperName, CSTORE_FDW_NAME, NAMEDATALEN) == 0)
{
CreateCStoreDatabaseDirectory(MyDatabaseId);
}
}
else if (nodeTag(parseTree) == T_CreateForeignTableStmt)
{
CreateForeignTableStmt *createStatement = (CreateForeignTableStmt *) parseTree;
Oid relationId = RangeVarGetRelid(createStatement->base.relation,
AccessShareLock, false);
if (CStoreTable(relationId))
{
TableWriteState *writeState = NULL;
Relation relation = heap_open(relationId, ExclusiveLock);
TupleDesc tupleDescriptor = RelationGetDescr(relation);
CStoreFdwOptions *cstoreFdwOptions = CStoreGetOptions(relationId);
/*
* Initialize state to write to the cstore file. This creates an
* empty data file and a valid footer file for the table.
*/
writeState = CStoreBeginWrite(cstoreFdwOptions->filename,
cstoreFdwOptions->compressionType,
cstoreFdwOptions->stripeRowCount,
cstoreFdwOptions->blockRowCount,
tupleDescriptor);
CStoreEndWrite(writeState);
heap_close(relation, ExclusiveLock);
}
}
PG_RETURN_NULL();
}
/*
* CStoreProcessUtility is the hook for handling utility commands. This function
* intercepts "COPY cstore_table FROM" statements, and redirects execution to
* CopyIntoCStoreTable function. For DROP FOREIGN TABLE commands, it stores the
* file path used for the table before calling the previous/standard utility
* command and then deletes the file once the drop is successful. For all other
* utility statements, the function calls the previous utility hook or the
* standard utility command.
*/
static void
CStoreProcessUtility(Node *parseTree, const char *queryString,
ProcessUtilityContext context, ParamListInfo paramListInfo,
DestReceiver *destReceiver, char *completionTag)
{
bool copyIntoCStoreTable = false;
bool dropCStoreTable = false;
char *tableFilename = NULL;
/* check if the statement is a "COPY cstore_table FROM ..." statement */
if (nodeTag(parseTree) == T_CopyStmt)
{
CopyStmt *copyStatement = (CopyStmt *) parseTree;
if (copyStatement->is_from)
{
Oid relationId = RangeVarGetRelid(copyStatement->relation,
AccessShareLock, false);
if (CStoreTable(relationId))
{
copyIntoCStoreTable = true;
}
}
}
/*
* Check if the statement is a "DROP FOREIGN TABLE cstore_table ..."
* statement and store the filename for that table if it is.
*/
if (nodeTag(parseTree) == T_DropStmt)
{
DropStmt *dropStatement = (DropStmt *) parseTree;
if (dropStatement->removeType == OBJECT_FOREIGN_TABLE)
{
ListCell *dropObjectCell = NULL;
foreach(dropObjectCell, dropStatement->objects)
{
List *tableNameList = (List *) lfirst(dropObjectCell);
RangeVar *rangeVar = makeRangeVarFromNameList(tableNameList);
Oid relationId = RangeVarGetRelid(rangeVar, AccessShareLock, true);
if (CStoreTable(relationId))
{
CStoreFdwOptions *cstoreFdwOptions = CStoreGetOptions(relationId);
tableFilename = cstoreFdwOptions->filename;
/* mark that this is a drop command for a cstore table */
dropCStoreTable = true;
}
}
}
}
if (copyIntoCStoreTable)
{
uint64 processed = CopyIntoCStoreTable((CopyStmt *) parseTree, queryString);
if (completionTag != NULL)
{
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
"COPY " UINT64_FORMAT, processed);
}
}
else if (PreviousProcessUtilityHook != NULL)
{
PreviousProcessUtilityHook(parseTree, queryString, context, paramListInfo,
destReceiver, completionTag);
}
else
{
standard_ProcessUtility(parseTree, queryString, context, paramListInfo,
destReceiver, completionTag);
}
if (dropCStoreTable)
{
DeleteCStoreTableFiles(tableFilename);
}
}
/*
* CStoreTable checks if the given table name belongs to a foreign columnar store
* table. If it does, the function returns true. Otherwise, it returns false.
*/
static bool
CStoreTable(Oid relationId)
{
bool cstoreTable = false;
char relationKind = 0;
if (relationId == InvalidOid)
{
return false;
}
relationKind = get_rel_relkind(relationId);
if (relationKind == RELKIND_FOREIGN_TABLE)
{
ForeignTable *foreignTable = GetForeignTable(relationId);
ForeignServer *server = GetForeignServer(foreignTable->serverid);
ForeignDataWrapper *foreignDataWrapper = GetForeignDataWrapper(server->fdwid);
char *foreignWrapperName = foreignDataWrapper->fdwname;
if (strncmp(foreignWrapperName, CSTORE_FDW_NAME, NAMEDATALEN) == 0)
{
cstoreTable = true;
}
}
return cstoreTable;
}
/*
* CopyIntoCStoreTable handles a "COPY cstore_table FROM" statement. This
* function uses the COPY command's functions to read and parse rows from
* the data source specified in the COPY statement. The function then writes
* each row to the file specified in the cstore foreign table options. Finally,
* the function returns the number of copied rows.
*/
static uint64
CopyIntoCStoreTable(const CopyStmt *copyStatement, const char *queryString)
{
uint64 processedRowCount = 0;
Relation relation = NULL;
Oid relationId = InvalidOid;
TupleDesc tupleDescriptor = NULL;
uint32 columnCount = 0;
CopyState copyState = NULL;
bool nextRowFound = true;
Datum *columnValues = NULL;
bool *columnNulls = NULL;
TableWriteState *writeState = NULL;
CStoreFdwOptions *cstoreFdwOptions = NULL;
MemoryContext tupleContext = NULL;
List *columnNameList = copyStatement->attlist;
if (columnNameList != NULL)
{
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("copy column list is not supported")));
}
/*
* We disallow copy from file or program except to superusers. These checks
* are based on the checks in DoCopy() function of copy.c.
*/
if (copyStatement->filename != NULL && !superuser())
{
if (copyStatement->is_program)
{
ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from a program"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
else
{
ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from a file"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
}
Assert(copyStatement->relation != NULL);
/*
* Open and lock the relation. We acquire ExclusiveLock to allow concurrent
* reads, but block concurrent writes.
*/
relation = heap_openrv(copyStatement->relation, ExclusiveLock);
relationId = RelationGetRelid(relation);
/* allocate column values and nulls arrays */
tupleDescriptor = RelationGetDescr(relation);
columnCount = tupleDescriptor->natts;
columnValues = palloc0(columnCount * sizeof(Datum));
columnNulls = palloc0(columnCount * sizeof(bool));
cstoreFdwOptions = CStoreGetOptions(relationId);
/*
* We create a new memory context called tuple context, and read and write
* each row's values within this memory context. After each read and write,
* we reset the memory context. That way, we immediately release memory
* allocated for each row, and don't bloat memory usage with large input
* files.
*/
tupleContext = AllocSetContextCreate(CurrentMemoryContext,
"CStore COPY Row Memory Context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* init state to read from COPY data source */
copyState = BeginCopyFrom(relation, copyStatement->filename,
copyStatement->is_program, NIL,
copyStatement->options);
/* init state to write to the cstore file */
writeState = CStoreBeginWrite(cstoreFdwOptions->filename,
cstoreFdwOptions->compressionType,
cstoreFdwOptions->stripeRowCount,
cstoreFdwOptions->blockRowCount,
tupleDescriptor);
while (nextRowFound)
{
/* read the next row in tupleContext */
MemoryContext oldContext = MemoryContextSwitchTo(tupleContext);
nextRowFound = NextCopyFrom(copyState, NULL, columnValues, columnNulls, NULL);
MemoryContextSwitchTo(oldContext);
/* write the row to the cstore file */
if (nextRowFound)
{
CStoreWriteRow(writeState, columnValues, columnNulls);
processedRowCount++;
}
MemoryContextReset(tupleContext);
}
/* end read/write sessions and close the relation */
EndCopyFrom(copyState);
CStoreEndWrite(writeState);
heap_close(relation, ExclusiveLock);
return processedRowCount;
}
/*
* CreateCStoreDatabaseDirectory creates the directory (and parent directories,
* if needed) used to store automatically managed cstore_fdw files. The path to
* the directory is $PGDATA/cstore_fdw/{databaseOid}.
*/
static void
CreateCStoreDatabaseDirectory(Oid databaseOid)
{
bool cstoreDirectoryExists = false;
bool databaseDirectoryExists = false;
StringInfo cstoreDatabaseDirectoryPath = NULL;
StringInfo cstoreDirectoryPath = makeStringInfo();
appendStringInfo(cstoreDirectoryPath, "%s/%s", DataDir, CSTORE_FDW_NAME);
cstoreDirectoryExists = DirectoryExists(cstoreDirectoryPath);
if (!cstoreDirectoryExists)
{
CreateDirectory(cstoreDirectoryPath);
}
cstoreDatabaseDirectoryPath = makeStringInfo();
appendStringInfo(cstoreDatabaseDirectoryPath, "%s/%s/%u", DataDir,
CSTORE_FDW_NAME, databaseOid);
databaseDirectoryExists = DirectoryExists(cstoreDatabaseDirectoryPath);
if (!databaseDirectoryExists)
{
CreateDirectory(cstoreDatabaseDirectoryPath);
}
}
/* DirectoryExists checks if a directory exists for the given directory name. */
static bool
DirectoryExists(StringInfo directoryName)
{
bool directoryExists = true;
struct stat directoryStat;
int statOK = stat(directoryName->data, &directoryStat);
if (statOK == 0)
{
/* file already exists; check that it is a directory */
if (!S_ISDIR(directoryStat.st_mode))
{
ereport(ERROR, (errmsg("\"%s\" is not a directory", directoryName->data),
errhint("You need to remove or rename the file \"%s\".",
directoryName->data)));
}
}
else
{
if (errno == ENOENT)
{
directoryExists = false;
}
else
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not stat directory \"%s\": %m",
directoryName->data)));
}
}
return directoryExists;
}
/* CreateDirectory creates a new directory with the given directory name. */
static void
CreateDirectory(StringInfo directoryName)
{
int makeOK = mkdir(directoryName->data, S_IRWXU);
if (makeOK != 0)
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not create directory \"%s\": %m",
directoryName->data)));
}
}
/*
* DeleteCStoreTableFiles deletes the data and footer files for a cstore table
* whose data filename is given.
*/
static void
DeleteCStoreTableFiles(char *filename)
{
int dataFileRemoved = 0;
int footerFileRemoved = 0;
StringInfo tableFooterFilename = makeStringInfo();
appendStringInfo(tableFooterFilename, "%s%s", filename, CSTORE_FOOTER_FILE_SUFFIX);
/* delete the footer file */
footerFileRemoved = unlink(tableFooterFilename->data);
if (footerFileRemoved != 0)
{
ereport(WARNING, (errcode_for_file_access(),
errmsg("could not delete file \"%s\": %m",
tableFooterFilename->data)));
}
/* delete the data file */
dataFileRemoved = unlink(filename);
if (dataFileRemoved != 0)
{
ereport(WARNING, (errcode_for_file_access(),
errmsg("could not delete file \"%s\": %m",
filename)));
}
}
/*
* cstore_table_size returns the total on-disk size of a cstore table in bytes.
* The result includes the sizes of data file and footer file.
*/
Datum
cstore_table_size(PG_FUNCTION_ARGS)
{
Oid relationId = PG_GETARG_OID(0);
int64 tableSize = 0;
CStoreFdwOptions *cstoreFdwOptions = NULL;
char *dataFilename = NULL;
StringInfo footerFilename = NULL;
int dataFileStatResult = 0;
int footerFileStatResult = 0;
struct stat dataFileStatBuffer;
struct stat footerFileStatBuffer;
bool cstoreTable = CStoreTable(relationId);
if (!cstoreTable)
{
ereport(ERROR, (errmsg("relation is not a cstore table")));
}
cstoreFdwOptions = CStoreGetOptions(relationId);
dataFilename = cstoreFdwOptions->filename;
dataFileStatResult = stat(dataFilename, &dataFileStatBuffer);
if (dataFileStatResult != 0)
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", dataFilename)));
}
footerFilename = makeStringInfo();
appendStringInfo(footerFilename, "%s%s", dataFilename,
CSTORE_FOOTER_FILE_SUFFIX);
footerFileStatResult = stat(footerFilename->data, &footerFileStatBuffer);
if (footerFileStatResult != 0)
{
ereport(ERROR, (errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m",
footerFilename->data)));
}
tableSize += dataFileStatBuffer.st_size;
tableSize += footerFileStatBuffer.st_size;
PG_RETURN_INT64(tableSize);
}
/*
* cstore_fdw_handler creates and returns a struct with pointers to foreign
* table callback functions.
*/
Datum
cstore_fdw_handler(PG_FUNCTION_ARGS)
{
FdwRoutine *fdwRoutine = makeNode(FdwRoutine);
fdwRoutine->GetForeignRelSize = CStoreGetForeignRelSize;
fdwRoutine->GetForeignPaths = CStoreGetForeignPaths;
fdwRoutine->GetForeignPlan = CStoreGetForeignPlan;
fdwRoutine->ExplainForeignScan = CStoreExplainForeignScan;
fdwRoutine->BeginForeignScan = CStoreBeginForeignScan;
fdwRoutine->IterateForeignScan = CStoreIterateForeignScan;
fdwRoutine->ReScanForeignScan = CStoreReScanForeignScan;
fdwRoutine->EndForeignScan = CStoreEndForeignScan;
fdwRoutine->AnalyzeForeignTable = CStoreAnalyzeForeignTable;
PG_RETURN_POINTER(fdwRoutine);
}
/*
* cstore_fdw_validator validates options given to one of the following commands:
* foreign data wrapper, server, user mapping, or foreign table. This function
* errors out if the given option name or its value is considered invalid.
*/
Datum
cstore_fdw_validator(PG_FUNCTION_ARGS)
{
Datum optionArray = PG_GETARG_DATUM(0);
Oid optionContextId = PG_GETARG_OID(1);
List *optionList = untransformRelOptions(optionArray);
ListCell *optionCell = NULL;
char *filename = NULL;
char *compressionTypeString = NULL;
char *stripeRowCountString = NULL;
char *blockRowCountString = NULL;
foreach(optionCell, optionList)
{
DefElem *optionDef = (DefElem *) lfirst(optionCell);
char *optionName = optionDef->defname;
bool optionValid = false;
int32 optionIndex = 0;
for (optionIndex = 0; optionIndex < ValidOptionCount; optionIndex++)
{
const CStoreValidOption *validOption = &(ValidOptionArray[optionIndex]);
if ((optionContextId == validOption->optionContextId) &&
(strncmp(optionName, validOption->optionName, NAMEDATALEN) == 0))
{
optionValid = true;
break;
}
}
/* if invalid option, display an informative error message */
if (!optionValid)
{
StringInfo optionNamesString = OptionNamesString(optionContextId);
ereport(ERROR, (errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
errmsg("invalid option \"%s\"", optionName),
errhint("Valid options in this context are: %s",
optionNamesString->data)));
}
if (strncmp(optionName, OPTION_NAME_FILENAME, NAMEDATALEN) == 0)
{
filename = defGetString(optionDef);
}
else if (strncmp(optionName, OPTION_NAME_COMPRESSION_TYPE, NAMEDATALEN) == 0)
{
compressionTypeString = defGetString(optionDef);
}
else if (strncmp(optionName, OPTION_NAME_STRIPE_ROW_COUNT, NAMEDATALEN) == 0)
{
stripeRowCountString = defGetString(optionDef);
}
else if (strncmp(optionName, OPTION_NAME_BLOCK_ROW_COUNT, NAMEDATALEN) == 0)
{
blockRowCountString = defGetString(optionDef);
}
}
if (optionContextId == ForeignTableRelationId)
{
ValidateForeignTableOptions(filename, compressionTypeString,
stripeRowCountString, blockRowCountString);
}
PG_RETURN_VOID();
}
/*
* OptionNamesString finds all options that are valid for the current context,
* and concatenates these option names in a comma separated string. The function
* is unchanged from mongo_fdw.
*/
static StringInfo
OptionNamesString(Oid currentContextId)
{
StringInfo optionNamesString = makeStringInfo();
bool firstOptionAppended = false;
int32 optionIndex = 0;
for (optionIndex = 0; optionIndex < ValidOptionCount; optionIndex++)
{
const CStoreValidOption *validOption = &(ValidOptionArray[optionIndex]);
/* if option belongs to current context, append option name */
if (currentContextId == validOption->optionContextId)
{
if (firstOptionAppended)
{
appendStringInfoString(optionNamesString, ", ");
}
appendStringInfoString(optionNamesString, validOption->optionName);
firstOptionAppended = true;
}
}
return optionNamesString;
}
/*
* CStoreGetOptions returns the option values to be used when reading and writing
* the cstore file. To resolve these values, the function checks options for the
* foreign table, and if not present, falls back to default values. This function
* errors out if given option values are considered invalid.
*/
static CStoreFdwOptions *
CStoreGetOptions(Oid foreignTableId)
{
CStoreFdwOptions *cstoreFdwOptions = NULL;
char *filename = NULL;
CompressionType compressionType = DEFAULT_COMPRESSION_TYPE;
int32 stripeRowCount = DEFAULT_STRIPE_ROW_COUNT;
int32 blockRowCount = DEFAULT_BLOCK_ROW_COUNT;
char *compressionTypeString = NULL;
char *stripeRowCountString = NULL;
char *blockRowCountString = NULL;
filename = CStoreGetOptionValue(foreignTableId, OPTION_NAME_FILENAME);
compressionTypeString = CStoreGetOptionValue(foreignTableId,
OPTION_NAME_COMPRESSION_TYPE);
stripeRowCountString = CStoreGetOptionValue(foreignTableId,
OPTION_NAME_STRIPE_ROW_COUNT);
blockRowCountString = CStoreGetOptionValue(foreignTableId,
OPTION_NAME_BLOCK_ROW_COUNT);
ValidateForeignTableOptions(filename, compressionTypeString,
stripeRowCountString, blockRowCountString);
/* parse provided options */
if (compressionTypeString != NULL)
{
compressionType = ParseCompressionType(compressionTypeString);
}
if (stripeRowCountString != NULL)
{
stripeRowCount = pg_atoi(stripeRowCountString, sizeof(int32), 0);
}
if (blockRowCountString != NULL)
{
blockRowCount = pg_atoi(blockRowCountString, sizeof(int32), 0);
}
/* set default filename if it is not provided */
if (filename == NULL)
{
filename = CStoreDefaultFilePath(foreignTableId);
}
cstoreFdwOptions = palloc0(sizeof(CStoreFdwOptions));
cstoreFdwOptions->filename = filename;
cstoreFdwOptions->compressionType = compressionType;
cstoreFdwOptions->stripeRowCount = stripeRowCount;
cstoreFdwOptions->blockRowCount = blockRowCount;
return cstoreFdwOptions;
}
/*
* CStoreGetOptionValue walks over foreign table and foreign server options, and
* looks for the option with the given name. If found, the function returns the
* option's value. This function is unchanged from mongo_fdw.
*/
static char *
CStoreGetOptionValue(Oid foreignTableId, const char *optionName)
{
ForeignTable *foreignTable = NULL;
ForeignServer *foreignServer = NULL;
List *optionList = NIL;
ListCell *optionCell = NULL;
char *optionValue = NULL;
foreignTable = GetForeignTable(foreignTableId);
foreignServer = GetForeignServer(foreignTable->serverid);
optionList = list_concat(optionList, foreignTable->options);
optionList = list_concat(optionList, foreignServer->options);
foreach(optionCell, optionList)
{
DefElem *optionDef = (DefElem *) lfirst(optionCell);
char *optionDefName = optionDef->defname;
if (strncmp(optionDefName, optionName, NAMEDATALEN) == 0)
{
optionValue = defGetString(optionDef);
break;
}
}
return optionValue;
}
/*
* ValidateForeignTableOptions verifies if given options are valid cstore_fdw
* foreign table options. This function errors out if given option value is
* considered invalid.
*/
static void
ValidateForeignTableOptions(char *filename, char *compressionTypeString,
char *stripeRowCountString, char *blockRowCountString)
{
/* we currently do not have any checks for filename */
(void) filename;
/* check if the provided compression type is valid */
if (compressionTypeString != NULL)
{
CompressionType compressionType = ParseCompressionType(compressionTypeString);
if (compressionType == COMPRESSION_TYPE_INVALID)
{
ereport(ERROR, (errmsg("invalid compression type"),
errhint("Valid options are: %s",
COMPRESSION_STRING_DELIMITED_LIST)));
}
}
/* check if the provided stripe row count has correct format and range */
if (stripeRowCountString != NULL)
{
/* pg_atoi() errors out if the given string is not a valid 32-bit integer */
int32 stripeRowCount = pg_atoi(stripeRowCountString, sizeof(int32), 0);
if (stripeRowCount < STRIPE_ROW_COUNT_MINIMUM ||
stripeRowCount > STRIPE_ROW_COUNT_MAXIMUM)
{
ereport(ERROR, (errmsg("invalid stripe row count"),
errhint("Stripe row count must be an integer between "
"%d and %d", STRIPE_ROW_COUNT_MINIMUM,
STRIPE_ROW_COUNT_MAXIMUM)));
}
}
/* check if the provided block row count has correct format and range */
if (blockRowCountString != NULL)
{
/* pg_atoi() errors out if the given string is not a valid 32-bit integer */
int32 blockRowCount = pg_atoi(blockRowCountString, sizeof(int32), 0);
if (blockRowCount < BLOCK_ROW_COUNT_MINIMUM ||
blockRowCount > BLOCK_ROW_COUNT_MAXIMUM)
{
ereport(ERROR, (errmsg("invalid block row count"),
errhint("Block row count must be an integer between "
"%d and %d", BLOCK_ROW_COUNT_MINIMUM,
BLOCK_ROW_COUNT_MAXIMUM)));
}
}
}
/*
* CStoreDefaultFilePath constructs the default file path to use for a cstore_fdw
* table. The path is of the form $PGDATA/cstore_fdw/{databaseOid}/{relfilenode}.
*/
static char *
CStoreDefaultFilePath(Oid foreignTableId)
{
Relation relation = relation_open(foreignTableId, AccessShareLock);
RelFileNode relationFileNode = relation->rd_node;
Oid databaseOid = relationFileNode.dbNode;
Oid relationFileOid = relationFileNode.relNode;
StringInfo cstoreFilePath = makeStringInfo();
appendStringInfo(cstoreFilePath, "%s/%s/%u/%u", DataDir, CSTORE_FDW_NAME,
databaseOid, relationFileOid);
relation_close(relation, AccessShareLock);
return cstoreFilePath->data;
}
/* ParseCompressionType converts a string to a compression type. */
static CompressionType
ParseCompressionType(const char *compressionTypeString)
{
CompressionType compressionType = COMPRESSION_TYPE_INVALID;
Assert(compressionTypeString != NULL);
if (strncmp(compressionTypeString, COMPRESSION_STRING_NONE, NAMEDATALEN) == 0)
{
compressionType = COMPRESSION_NONE;
}
else if (strncmp(compressionTypeString, COMPRESSION_STRING_PG_LZ, NAMEDATALEN) == 0)
{
compressionType = COMPRESSION_PG_LZ;
}
return compressionType;
}
/*
* CStoreGetForeignRelSize obtains relation size estimates for a foreign table and
* puts its estimate for row count into baserel->rows.
*/
static void
CStoreGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel, Oid foreignTableId)
{
CStoreFdwOptions *cstoreFdwOptions = CStoreGetOptions(foreignTableId);
double tupleCountEstimate = TupleCountEstimate(baserel, cstoreFdwOptions->filename);
double rowSelectivity = clauselist_selectivity(root, baserel->baserestrictinfo,
0, JOIN_INNER, NULL);
double outputRowCount = clamp_row_est(tupleCountEstimate * rowSelectivity);
baserel->rows = outputRowCount;
}
/*
* CStoreGetForeignPaths creates possible access paths for a scan on the foreign
* table. We currently have one possible access path. This path filters out row
* blocks that are refuted by where clauses, and only returns values for the
* projected columns.
*/
static void
CStoreGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel, Oid foreignTableId)
{
Path *foreignScanPath = NULL;
CStoreFdwOptions *cstoreFdwOptions = CStoreGetOptions(foreignTableId);
Relation relation = heap_open(foreignTableId, AccessShareLock);
/*
* We skip reading columns that are not in query. Here we assume that all
* columns in relation have the same width, and estimate the number pages
* that will be read by query.
*
* Ideally, we should also take into account the row blocks that will be
* suppressed. But for that we need to know which columns are used for
* sorting. If we wrongly assume that we are sorted by a specific column
* and underestimate the page count, planner may choose nested loop join
* in a place it shouldn't be used. Choosing merge join or hash join is
* usually safer than nested loop join, so we take the more conservative
* approach and assume all rows in the columnar store file will be read.
* We intend to fix this in later version by improving the row sampling
* algorithm and using the correlation statistics to detect which columns
* are in stored in sorted order.
*/
List *queryColumnList = ColumnList(baserel);
uint32 queryColumnCount = list_length(queryColumnList);
BlockNumber relationPageCount = PageCount(cstoreFdwOptions->filename);
uint32 relationColumnCount = RelationGetNumberOfAttributes(relation);
double queryColumnRatio = (double) queryColumnCount / relationColumnCount;
double queryPageCount = relationPageCount * queryColumnRatio;
double totalDiskAccessCost = seq_page_cost * queryPageCount;
double tupleCountEstimate = TupleCountEstimate(baserel, cstoreFdwOptions->filename);
/*
* We estimate costs almost the same way as cost_seqscan(), thus assuming
* that I/O costs are equivalent to a regular table file of the same size.
*/
double filterCostPerTuple = baserel->baserestrictcost.per_tuple;
double cpuCostPerTuple = cpu_tuple_cost + filterCostPerTuple;
double totalCpuCost = cpuCostPerTuple * tupleCountEstimate;
double startupCost = baserel->baserestrictcost.startup;
double totalCost = startupCost + totalCpuCost + totalDiskAccessCost;
/* create a foreign path node and add it as the only possible path */
foreignScanPath = (Path *) create_foreignscan_path(root, baserel, baserel->rows,
startupCost, totalCost,
NIL, /* no known ordering */
NULL, /* not parameterized */
NIL); /* no fdw_private */