pgbench: Ensure previous progress message is fully cleared when updating.

During pgbench's table initialization, progress updates could display
leftover characters from the previous message if the new message
was shorter. This commit resolves the issue by appending spaces to
the current message to fully overwrite any remaining characters from
the previous line.

Back-patch to all the supported versions.

Author: Yushi Ogiwara, Tatsuo Ishii, Fujii Masao
Reviewed-by: Tatsuo Ishii, Fujii Masao
Discussion: https://postgr.es/m/9a9b8b95b6a709877ae48ad5b0c59bb9@oss.nttdata.com

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index e5ee1a0ffa2f0eb8a6569787271c4e3dec835576..c0825ae6790b5b52c1dffafc31fd91ebfd6c62a4 100644 (file)
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -4916,6 +4916,8 @@ initGenerateDataClientSide(PGconn *con)
        PGresult   *res;
        int                     i;
        int64           k;
+       int                     chars = 0;
+       int                     prev_chars = 0;
        char       *copy_statement;
 
        /* used to track elapsed time and estimate of the remaining time */
@@ -5001,10 +5003,10 @@ initGenerateDataClientSide(PGconn *con)
                        double          elapsed_sec = PG_TIME_GET_DOUBLE(pg_time_now() - start);
                        double          remaining_sec = ((double) scale * naccounts - j) * elapsed_sec / j;
 
-                       fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)%c",
-                                       j, (int64) naccounts * scale,
-                                       (int) (((int64) j * 100) / (naccounts * (int64) scale)),
-                                       elapsed_sec, remaining_sec, eol);
+                       chars = fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)",
+                                                       j, (int64) naccounts * scale,
+                                                       (int) (((int64) j * 100) / (naccounts * (int64) scale)),
+                                                       elapsed_sec, remaining_sec);
                }
                /* let's not call the timing for each row, but only each 100 rows */
                else if (use_quiet && (j % 100 == 0))
@@ -5015,14 +5017,24 @@ initGenerateDataClientSide(PGconn *con)
                        /* have we reached the next interval (or end)? */
                        if ((j == scale * naccounts) || (elapsed_sec >= log_interval * LOG_STEP_SECONDS))
                        {
-                               fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)%c",
-                                               j, (int64) naccounts * scale,
-                                               (int) (((int64) j * 100) / (naccounts * (int64) scale)), elapsed_sec, remaining_sec, eol);
+                               chars = fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)",
+                                                               j, (int64) naccounts * scale,
+                                                               (int) (((int64) j * 100) / (naccounts * (int64) scale)), elapsed_sec, remaining_sec);
 
                                /* skip to the next interval */
                                log_interval = (int) ceil(elapsed_sec / LOG_STEP_SECONDS);
                        }
                }
+
+               /*
+                * If the previous progress message is longer than the current one,
+                * add spaces to the current line to fully overwrite any remaining
+                * characters from the previous message.
+                */
+               if (prev_chars > chars)
+                       fprintf(stderr, "%*c", prev_chars - chars, ' ');
+               fputc(eol, stderr);
+               prev_chars = chars;
        }
 
        if (eol != '\n')