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846878c6bb
PostgreSQL scan functions might allocate memory that needs to live for the duration of the scan. This applies also to functions that are called during the scan, such as getting the next tuple. To avoid situations when such functions are accidentally called on, e.g., a short-lived per-tuple context, add a explicit scan memory context to the Scanner interface that wraps the PostgreSQL scan API.
132 lines
4.1 KiB
C
132 lines
4.1 KiB
C
/*
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* This file and its contents are licensed under the Apache License 2.0.
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* Please see the included NOTICE for copyright information and
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* LICENSE-APACHE for a copy of the license.
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*/
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#ifndef TIMESCALEDB_SCAN_ITERATOR_H
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#define TIMESCALEDB_SCAN_ITERATOR_H
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#include <postgres.h>
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#include <utils/palloc.h>
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#include "scanner.h"
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#include "ts_catalog/catalog.h"
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#define EMBEDDED_SCAN_KEY_SIZE 5
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typedef struct ScanIterator
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{
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ScannerCtx ctx;
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TupleInfo *tinfo;
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ScanKeyData scankey[EMBEDDED_SCAN_KEY_SIZE];
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} ScanIterator;
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#define ts_scan_iterator_create(catalog_table_id, lock_mode, mctx) \
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(ScanIterator) \
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{ \
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.ctx = { \
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.internal = { \
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.ended = true, \
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.scan_mcxt = CurrentMemoryContext, \
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}, \
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.table = catalog_get_table_id(ts_catalog_get(), catalog_table_id), \
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.nkeys = 0, \
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.scandirection = ForwardScanDirection, \
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.lockmode = lock_mode, \
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.result_mctx = mctx, \
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.flags = SCANNER_F_NOFLAGS, \
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}, \
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}
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static inline TupleInfo *
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ts_scan_iterator_tuple_info(const ScanIterator *iterator)
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{
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return iterator->tinfo;
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}
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static inline TupleTableSlot *
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ts_scan_iterator_slot(const ScanIterator *iterator)
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{
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return iterator->tinfo->slot;
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}
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static inline HeapTuple
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ts_scan_iterator_fetch_heap_tuple(const ScanIterator *iterator, bool materialize, bool *should_free)
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{
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return ts_scanner_fetch_heap_tuple(iterator->tinfo, materialize, should_free);
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}
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static inline TupleDesc
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ts_scan_iterator_tupledesc(const ScanIterator *iterator)
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{
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return ts_scanner_get_tupledesc(iterator->tinfo);
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}
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static inline MemoryContext
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ts_scan_iterator_get_result_memory_context(const ScanIterator *iterator)
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{
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return iterator->ctx.result_mctx;
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}
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static inline void *
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ts_scan_iterator_alloc_result(const ScanIterator *iterator, Size size)
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{
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return MemoryContextAllocZero(iterator->ctx.result_mctx, size);
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}
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static inline void
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ts_scan_iterator_start_scan(ScanIterator *iterator)
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{
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ts_scanner_start_scan(&(iterator)->ctx);
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}
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static inline TupleInfo *
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ts_scan_iterator_next(ScanIterator *iterator)
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{
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iterator->tinfo = ts_scanner_next(&(iterator)->ctx);
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return iterator->tinfo;
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}
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static inline void
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ts_scan_iterator_scan_key_reset(ScanIterator *iterator)
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{
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iterator->ctx.nkeys = 0;
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}
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static inline bool
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ts_scan_iterator_is_started(ScanIterator *iterator)
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{
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return iterator->ctx.internal.started;
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}
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void TSDLLEXPORT ts_scan_iterator_set_index(ScanIterator *iterator, CatalogTable table,
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int indexid);
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void TSDLLEXPORT ts_scan_iterator_end(ScanIterator *iterator);
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void TSDLLEXPORT ts_scan_iterator_close(ScanIterator *iterator);
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void TSDLLEXPORT ts_scan_iterator_scan_key_init(ScanIterator *iterator, AttrNumber attributeNumber,
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StrategyNumber strategy, RegProcedure procedure,
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Datum argument);
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/*
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* Reset the scan to use a new scan key.
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*
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* Note that the scan key should typically be reinitialized before a rescan.
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*/
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void TSDLLEXPORT ts_scan_iterator_rescan(ScanIterator *iterator);
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static inline void
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ts_scan_iterator_start_or_restart_scan(ScanIterator *iterator)
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{
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if (ts_scan_iterator_is_started(iterator))
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ts_scan_iterator_rescan(iterator);
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else
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ts_scan_iterator_start_scan(iterator);
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}
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/* You must use `ts_scan_iterator_close` if terminating this loop early */
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#define ts_scanner_foreach(scan_iterator) \
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for (ts_scan_iterator_start_scan((scan_iterator)); \
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ts_scan_iterator_next(scan_iterator) != NULL;)
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#endif /* TIMESCALEDB_SCAN_ITERATOR_H */
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