On Thu, Mar 1, 2018 at 2:47 PM, Peter Geoghegan <p...@bowt.ie> wrote: > No. Just an oversight. Looks like _bt_parallel_build_main() should > call pgstat_report_activity(), just like ParallelQueryMain(). > > I'll come up with a patch soon.
Attached patch has parallel CREATE INDEX propagate debug_query_string to workers. Workers go on to use this string as their own debug_query_string, as well as registering it using pgstat_report_activity(). Parallel CREATE INDEX pg_stat_activity entries will have a query text, too, which addresses Phil's complaint. I wasn't 100% sure if I should actually show the leader's debug_query_string within worker pg_stat_activity entries, since that isn't what parallel query uses (the QueryDesc/Estate query string in shared memory is *restored* as the debug_query_string for a parallel query worker, though). I eventually decided that this debug_query_string approach was okay. There is nothing remotely like a QueryDesc or EState passed to btbuild(). I can imagine specific issues with what I've done, such as a CREATE EXTENSION command that contains a CREATE INDEX, and yet shows a CREATE EXTENSION in pg_stat_activity for parallel workers. However, that's no different to what you'd see with a serial index build. Existing tcop/postgres.c pgstat_report_activity() calls are aligned with setting debug_query_string. -- Peter Geoghegan
From 1c380b337be86bb3c69cf70b39da1d3dd1fba18a Mon Sep 17 00:00:00 2001 From: Peter Geoghegan <p...@bowt.ie> Date: Wed, 7 Mar 2018 14:22:56 -0800 Subject: [PATCH] Report query text in parallel CREATE INDEX workers. Commit 4c728f38297 established that parallel query should propagate a debug_query_string to worker processes, and display query text in worker pg_stat_activity entries. Parallel CREATE INDEX should follow this precedent. This fixes an oversight in commit 9da0cc35. Author: Peter Geoghegan Reported-By: Phil Florent Discussion: https://postgr.es/m/cah2-wzkryapcqohbjkudkfni-hgfny31yjcbm-yp5ho-71i...@mail.gmail.com --- src/backend/access/nbtree/nbtsort.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c index f0c276b52a..098e0ce1be 100644 --- a/src/backend/access/nbtree/nbtsort.c +++ b/src/backend/access/nbtree/nbtsort.c @@ -86,6 +86,7 @@ #define PARALLEL_KEY_BTREE_SHARED UINT64CONST(0xA000000000000001) #define PARALLEL_KEY_TUPLESORT UINT64CONST(0xA000000000000002) #define PARALLEL_KEY_TUPLESORT_SPOOL2 UINT64CONST(0xA000000000000003) +#define PARALLEL_KEY_QUERY_TEXT UINT64CONST(0xA000000000000004) /* * DISABLE_LEADER_PARTICIPATION disables the leader's participation in @@ -1195,6 +1196,8 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) BTSpool *btspool = buildstate->spool; BTLeader *btleader = (BTLeader *) palloc0(sizeof(BTLeader)); bool leaderparticipates = true; + char *sharedquery; + int querylen; #ifdef DISABLE_LEADER_PARTICIPATION leaderparticipates = false; @@ -1223,9 +1226,8 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) snapshot = RegisterSnapshot(GetTransactionSnapshot()); /* - * Estimate size for at least two keys -- our own - * PARALLEL_KEY_BTREE_SHARED workspace, and PARALLEL_KEY_TUPLESORT - * tuplesort workspace + * Estimate size for our own PARALLEL_KEY_BTREE_SHARED workspace, and + * PARALLEL_KEY_TUPLESORT tuplesort workspace */ estbtshared = _bt_parallel_estimate_shared(snapshot); shm_toc_estimate_chunk(&pcxt->estimator, estbtshared); @@ -1234,7 +1236,7 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) /* * Unique case requires a second spool, and so we may have to account for - * a third shared workspace -- PARALLEL_KEY_TUPLESORT_SPOOL2 + * another shared workspace for that -- PARALLEL_KEY_TUPLESORT_SPOOL2 */ if (!btspool->isunique) shm_toc_estimate_keys(&pcxt->estimator, 2); @@ -1244,6 +1246,11 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) shm_toc_estimate_keys(&pcxt->estimator, 3); } + /* Finally, estimate PARALLEL_KEY_QUERY_TEXT space */ + querylen = strlen(debug_query_string); + shm_toc_estimate_chunk(&pcxt->estimator, querylen + 1); + shm_toc_estimate_keys(&pcxt->estimator, 1); + /* Everyone's had a chance to ask for space, so now create the DSM */ InitializeParallelDSM(pcxt); @@ -1293,6 +1300,11 @@ _bt_begin_parallel(BTBuildState *buildstate, bool isconcurrent, int request) shm_toc_insert(pcxt->toc, PARALLEL_KEY_TUPLESORT_SPOOL2, sharedsort2); } + /* Store query string for workers */ + sharedquery = (char *) shm_toc_allocate(pcxt->toc, querylen + 1); + memcpy(sharedquery, debug_query_string, querylen + 1); + shm_toc_insert(pcxt->toc, PARALLEL_KEY_QUERY_TEXT, sharedquery); + /* Launch workers, saving status for leader/caller */ LaunchParallelWorkers(pcxt); btleader->pcxt = pcxt; @@ -1459,6 +1471,7 @@ _bt_leader_participate_as_worker(BTBuildState *buildstate) void _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc) { + char *sharedquery; BTSpool *btspool; BTSpool *btspool2; BTShared *btshared; @@ -1475,7 +1488,14 @@ _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc) ResetUsage(); #endif /* BTREE_BUILD_STATS */ - /* Look up shared state */ + /* Set debug_query_string for individual workers first */ + sharedquery = shm_toc_lookup(toc, PARALLEL_KEY_QUERY_TEXT, false); + debug_query_string = sharedquery; + + /* Report the query string from leader */ + pgstat_report_activity(STATE_RUNNING, debug_query_string); + + /* Look up nbtree shared state */ btshared = shm_toc_lookup(toc, PARALLEL_KEY_BTREE_SHARED, false); /* Open relations using lock modes known to be obtained by index.c */ -- 2.14.1
