Re: Using COPY FREEZE in pgbench - Mailing list pgsql-hackers

Hi fabien,

>> So overall gain by the patch is around 15%, whereas the last test
>> before the commit was 14%.  It seems the patch is still beneficial
>> after the commit.
> 
> Yes, that's good!

Yeah!

> I had a quick look again, and about the comment:
> 
>  /*
>   * If partitioning is not enabled and server version is 14.0 or later, we
>   * can take account of freeze option of copy.
>   */
> 
> I'd suggest instead the shorter:
> 
>  /* use COPY with FREEZE on v14 and later without partioning */
> 
> Or maybe even to fully drop the comment, because the code is clear
> enough and the doc already says it.

I'd prefer to leave a comment. People (including me) tend to forget
things in the future, that are obvious now:-)

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 0c60077e1f..0f432767c2 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -220,6 +220,9 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
             data is generated in <command>pgbench</command> client and then
             sent to the server. This uses the client/server bandwidth
             extensively through a <command>COPY</command>.
+            <command>pgbench</command> uses the FREEZE option with 14 or later
+            versions of <productname>PostgreSQL</productname> to speed up
+            subsequent <command>VACUUM</command>, unless partitions are enabled.
             Using <literal>g</literal> causes logging to print one message
             every 100,000 rows while generating data for the
             <structname>pgbench_accounts</structname> table.
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 4aeccd93af..54d993075f 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -4119,6 +4119,7 @@ initGenerateDataClientSide(PGconn *con)
     PGresult   *res;
     int            i;
     int64        k;
+    char        *copy_statement;
 
     /* used to track elapsed time and estimate of the remaining time */
     pg_time_usec_t start;
@@ -4165,7 +4166,15 @@ initGenerateDataClientSide(PGconn *con)
     /*
      * accounts is big enough to be worth using COPY and tracking runtime
      */
-    res = PQexec(con, "copy pgbench_accounts from stdin");
+
+    /* use COPY with FREEZE on v14 and later without partioning */
+    if (partitions == 0 && PQserverVersion(con) >= 140000)
+        copy_statement = "copy pgbench_accounts from stdin with (freeze on)";
+    else
+        copy_statement = "copy pgbench_accounts from stdin";
+
+    res = PQexec(con, copy_statement);
+
     if (PQresultStatus(res) != PGRES_COPY_IN)
     {
         pg_log_fatal("unexpected copy in result: %s", PQerrorMessage(con));