diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 4835c48b448..b0e50307a0e 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -407,12 +407,6 @@ index_beginscan_internal(Relation indexRelation, scan->parallel_scan = pscan; scan->xs_temp_snap = temp_snap; - /* - * No batching by default, so set it to NULL. Will be initialized later if - * batching is requested and AM supports it. - */ - scan->xs_batches = NULL; - return scan; } @@ -463,6 +457,17 @@ index_rescan(IndexScanDesc scan, orderbys, norderbys); } +void +index_get_prefetch_stats(IndexScanDesc scan, int *accum, int *count, int *stalls, int *resets, int *skips) +{ + /* ugly */ + if (scan->xs_heapfetch->rs != NULL) + { + read_stream_prefetch_stats(scan->xs_heapfetch->rs, + accum, count, stalls, resets, skips); + } +} + /* ---------------- * index_endscan - end a scan * ---------------- @@ -1883,6 +1888,7 @@ index_scan_stream_read_next(ReadStream *stream, /* same block as before, don't need to read it */ if (scan->xs_batches->lastBlock == ItemPointerGetBlockNumber(tid)) { + read_stream_skip_block(stream); DEBUG_LOG("index_scan_stream_read_next: skip block (lastBlock)"); continue; } diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index 7e2792ead71..9c95b4e2878 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -136,6 +136,7 @@ static void show_memoize_info(MemoizeState *mstate, List *ancestors, ExplainState *es); static void show_hashagg_info(AggState *aggstate, ExplainState *es); static void show_indexsearches_info(PlanState *planstate, ExplainState *es); +static void show_indexprefetch_info(PlanState *planstate, ExplainState *es); static void show_tidbitmap_info(BitmapHeapScanState *planstate, ExplainState *es); static void show_instrumentation_count(const char *qlabel, int which, @@ -1966,6 +1967,7 @@ ExplainNode(PlanState *planstate, List *ancestors, show_instrumentation_count("Rows Removed by Filter", 1, planstate, es); show_indexsearches_info(planstate, es); + show_indexprefetch_info(planstate, es); break; case T_IndexOnlyScan: show_scan_qual(((IndexOnlyScan *) plan)->indexqual, @@ -1983,6 +1985,7 @@ ExplainNode(PlanState *planstate, List *ancestors, ExplainPropertyFloat("Heap Fetches", NULL, planstate->instrument->ntuples2, 0, es); show_indexsearches_info(planstate, es); + show_indexprefetch_info(planstate, es); break; case T_BitmapIndexScan: show_scan_qual(((BitmapIndexScan *) plan)->indexqualorig, @@ -3889,6 +3892,50 @@ show_indexsearches_info(PlanState *planstate, ExplainState *es) ExplainPropertyUInteger("Index Searches", NULL, nsearches, es); } +static void +show_indexprefetch_info(PlanState *planstate, ExplainState *es) +{ + Plan *plan = planstate->plan; + + int count = 0, + accum = 0, + stalls = 0, + resets = 0, + skips = 0; + + if (!es->analyze) + return; + + /* Initialize counters with stats from the local process first */ + switch (nodeTag(plan)) + { + case T_IndexScan: + { + IndexScanState *indexstate = ((IndexScanState *) planstate); + + count = indexstate->iss_PrefetchCount; + accum = indexstate->iss_PrefetchAccum; + stalls = indexstate->iss_PrefetchStalls; + resets = indexstate->iss_ResetCount; + skips = indexstate->iss_SkipCount; + + break; + } + default: + break; + } + + if (count > 0) + { + ExplainPropertyFloat("Prefetch Distance", NULL, (accum * 1.0 / count), 3, es); + ExplainPropertyUInteger("Prefetch Count", NULL, count, es); + ExplainPropertyUInteger("Prefetch Stalls", NULL, stalls, es); + ExplainPropertyUInteger("Prefetch Skips", NULL, skips, es); + ExplainPropertyUInteger("Prefetch Resets", NULL, resets, es); + } +} + + /* * Show exact/lossy pages for a BitmapHeapScan node */ diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c index 7fcaa37fe62..707badc4fdc 100644 --- a/src/backend/executor/nodeIndexscan.c +++ b/src/backend/executor/nodeIndexscan.c @@ -125,6 +125,13 @@ IndexNext(IndexScanState *node) node->iss_OrderByKeys, node->iss_NumOrderByKeys); } + index_get_prefetch_stats(scandesc, + &node->iss_PrefetchAccum, + &node->iss_PrefetchCount, + &node->iss_PrefetchStalls, + &node->iss_ResetCount, + &node->iss_SkipCount); + /* * ok, now that we have what we need, fetch the next tuple. */ @@ -1088,6 +1095,12 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags) indexstate->iss_RuntimeContext = NULL; } + indexstate->iss_PrefetchAccum = 0; + indexstate->iss_PrefetchCount = 0; + indexstate->iss_PrefetchStalls = 0; + indexstate->iss_ResetCount = 0; + indexstate->iss_SkipCount = 0; + /* * all done. */ diff --git a/src/backend/storage/aio/read_stream.c b/src/backend/storage/aio/read_stream.c index 0e7f5557f5c..e41189f6612 100644 --- a/src/backend/storage/aio/read_stream.c +++ b/src/backend/storage/aio/read_stream.c @@ -106,6 +106,12 @@ struct ReadStream bool advice_enabled; bool temporary; + int distance_accum; + int distance_count; + int distance_stalls; + int reset_count; + int skip_count; + /* * One-block buffer to support 'ungetting' a block number, to resolve flow * control problems when I/Os are split. @@ -180,6 +186,16 @@ read_stream_get_block(ReadStream *stream, void *per_buffer_data) { BlockNumber blocknum; + if (stream->distance > 1) + { + stream->distance_accum += stream->distance; + stream->distance_count += 1; + } + else + { + stream->distance_stalls += 1; + } + blocknum = stream->buffered_blocknum; if (blocknum != InvalidBlockNumber) stream->buffered_blocknum = InvalidBlockNumber; @@ -681,6 +697,12 @@ read_stream_begin_impl(int flags, stream->seq_until_processed = InvalidBlockNumber; stream->temporary = SmgrIsTemp(smgr); + stream->distance_accum = 0; + stream->distance_count = 0; + stream->distance_stalls = 0; + stream->reset_count = 0; + stream->skip_count = 0; + /* * Skip the initial ramp-up phase if the caller says we're going to be * reading the whole relation. This way we start out assuming we'll be @@ -771,6 +793,17 @@ read_stream_next_buffer(ReadStream *stream, void **per_buffer_data) { Buffer buffer; int16 oldest_buffer_index; +/* + if (stream->distance > 0) + { + stream->distance_accum += stream->distance; + stream->distance_count += 1; + } + else + { + stream->distance_stalls += 1; + } +*/ #ifndef READ_STREAM_DISABLE_FAST_PATH @@ -1046,6 +1079,8 @@ read_stream_reset(ReadStream *stream) /* Start off assuming data is cached. */ stream->distance = 1; + + stream->reset_count += 1; } /* @@ -1057,3 +1092,19 @@ read_stream_end(ReadStream *stream) read_stream_reset(stream); pfree(stream); } + +void +read_stream_prefetch_stats(ReadStream *stream, int *accum, int *count, int *stalls, int *resets, int *skips) +{ + *accum = stream->distance_accum; + *count = stream->distance_count; + *stalls = stream->distance_stalls; + *resets = stream->reset_count; + *skips = stream->skip_count; +} + +void +read_stream_skip_block(ReadStream *stream) +{ + stream->skip_count++; +} diff --git a/src/include/access/genam.h b/src/include/access/genam.h index 3a3a44be3a5..f1e5fdfd478 100644 --- a/src/include/access/genam.h +++ b/src/include/access/genam.h @@ -235,6 +235,7 @@ extern bytea *index_opclass_options(Relation indrel, AttrNumber attnum, Datum attoptions, bool validate); extern IndexScanBatch index_batch_alloc(int maxitems, bool want_itup); +extern void index_get_prefetch_stats(IndexScanDesc scan, int *accum, int *count, int *stalls, int *resets, int *skips); /* * index access method support routines (in genam.c) diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index e107d6e5f81..e91bc7ea35f 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -1722,6 +1722,12 @@ typedef struct IndexScanState IndexScanInstrumentation iss_Instrument; SharedIndexScanInstrumentation *iss_SharedInfo; + int iss_PrefetchAccum; + int iss_PrefetchCount; + int iss_PrefetchStalls; + int iss_ResetCount; + int iss_SkipCount; + /* These are needed for re-checking ORDER BY expr ordering */ pairingheap *iss_ReorderQueue; bool iss_ReachedEnd; diff --git a/src/include/storage/read_stream.h b/src/include/storage/read_stream.h index 9b0d65161d0..34e184a1690 100644 --- a/src/include/storage/read_stream.h +++ b/src/include/storage/read_stream.h @@ -102,4 +102,7 @@ extern ReadStream *read_stream_begin_smgr_relation(int flags, extern void read_stream_reset(ReadStream *stream); extern void read_stream_end(ReadStream *stream); +extern void read_stream_prefetch_stats(ReadStream *stream, int *accum, int *count, int *stalls, int *resets, int *skips); +extern void read_stream_skip_block(ReadStream *stream); + #endif /* READ_STREAM_H */