Report sort phase progress in parallel btree build

 We were already reporting it, but only after the parallel workers were
 finished, which is visibly much later than what happens in a serial
 build.
 
 With this change we report it when the leader starts its own sort phase
 when participating in the build (the normal case).  Now this might
 happen a little later than when the workers start their sorting phases,
 but a) communicating the actual phase start from workers is likely to be
 a hassle, and b) the sort phase start is pretty fuzzy anyway, since
 sorting per se is actually initiated by tuplesort.c internally earlier
 than tuplesort_performsort() is called.
 
 Backpatch to pg12, where the progress reporting code for CREATE INDEX
 went in.
 
 Reported-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
 Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
 Reviewed-by: Greg Nancarrow <gregn4422@gmail.com>
 Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
 Discussion: https://postgr.es/m/1128176d-1eee-55d4-37ca-e63644422adb
 
 

diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index 2c4d7f6e25a7c91d534a5bb74f013c21ee55ae99..5fa6ea8ad9a097a53be8d8c8ae8962b5f7b53a69 100644 (file)
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -547,6 +547,7 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
    }
 #endif                         /* BTREE_BUILD_STATS */
 
+   /* Execute the sort */
    pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE,
                                 PROGRESS_BTREE_PHASE_PERFORMSORT_1);
    tuplesort_performsort(btspool->sortstate);
@@ -1971,16 +1972,18 @@ _bt_parallel_scan_and_sort(BTSpool *btspool, BTSpool *btspool2,
                                       true, progress, _bt_build_callback,
                                       (void *) &buildstate, scan);
 
-   /*
-    * Execute this worker's part of the sort.
-    *
-    * Unlike leader and serial cases, we cannot avoid calling
-    * tuplesort_performsort() for spool2 if it ends up containing no dead
-    * tuples (this is disallowed for workers by tuplesort).
-    */
+   /* Execute this worker's part of the sort */
+   if (progress)
+       pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE,
+                                    PROGRESS_BTREE_PHASE_PERFORMSORT_1);
    tuplesort_performsort(btspool->sortstate);
    if (btspool2)
+   {
+       if (progress)
+           pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE,
+                                        PROGRESS_BTREE_PHASE_PERFORMSORT_2);
        tuplesort_performsort(btspool2->sortstate);
+   }
 
    /*
     * Done.  Record ambuild statistics, and whether we encountered a broken