Re: convert elog(LOG) calls to ereport

On Wed, Dec 02, 2020 at 02:26:24PM +0100, Peter Eisentraut wrote:
> There are a number of elog(LOG) calls that appear to be user-facing, so they
> should be ereport()s.

> @@ -8591,25 +8604,46 @@ LogCheckpointEnd(bool restartpoint)
> CheckpointStats.ckpt_sync_rels;
> average_msecs = (long) ((average_sync_time + 999) / 1000);
>
> - elog(LOG, "%s complete: wrote %d buffers (%.1f%%); "
> - "%d WAL file(s) added, %d removed, %d recycled; "
> - "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
> - "sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
> - "distance=%d kB, estimate=%d kB",

+1 to this change.

> @@ -1763,7 +1771,8 @@ pq_setkeepalivesidle(int idle, Port *port)
> #else
> if (idle != 0)
> {
> - elog(LOG, "setting the keepalive idle time is not supported");
> + ereport(LOG,
> + (errmsg("setting the keepalive idle time is not supported")));

+1

> --- a/src/backend/optimizer/geqo/geqo_erx.c
> +++ b/src/backend/optimizer/geqo/geqo_erx.c
> @@ -420,7 +420,8 @@ edge_failure(PlannerInfo *root, Gene *gene, int index, Edge *edge_table, int num
> }
> }
>
> - elog(LOG, "no edge found via random decision and total_edges == 4");
> + ereport(LOG,
> + (errmsg("no edge found via random decision and total_edges == 4")));

The user can't act upon this without reading the source code. This and the
other messages proposed in this file are better as elog().

> @@ -343,7 +346,8 @@ PGSharedMemoryCreate(Size size,
> * care.
> */
> if (!CloseHandle(hmap))
> - elog(LOG, "could not close handle to shared memory: error code %lu", GetLastError());
> + ereport(LOG,
> + (errmsg("could not close handle to shared memory: error code %lu", GetLastError())));

The numerous messages proposed in src/backend/port/ files are can't-happen
events, and there's little a DBA can do without reading the source code.
They're better as elog().

> @@ -6108,8 +6111,9 @@ backend_read_statsfile(void)
> /* Copy because timestamptz_to_str returns a static buffer */
> filetime = pstrdup(timestamptz_to_str(file_ts));
> mytime = pstrdup(timestamptz_to_str(cur_ts));
> - elog(LOG, "stats collector's time %s is later than backend local time %s",
> - filetime, mytime);
> + ereport(LOG,
> + (errmsg("statistics collector's time %s is later than backend local time %s",
> + filetime, mytime)));

+1

> @@ -769,10 +769,11 @@ StartupReplicationOrigin(void)
> replication_states[last_state].remote_lsn = disk_state.remote_lsn;
> last_state++;
>
> - elog(LOG, "recovered replication state of node %u to %X/%X",
> - disk_state.roident,
> - (uint32) (disk_state.remote_lsn >> 32),
> - (uint32) disk_state.remote_lsn);
> + ereport(LOG,
> + (errmsg("recovered replication state of node %u to %X/%X",
> + disk_state.roident,
> + (uint32) (disk_state.remote_lsn >> 32),
> + (uint32) disk_state.remote_lsn)));

+1

> @@ -1914,7 +1914,8 @@ FileClose(File file)
>
> /* in any case do the unlink */
> if (unlink(vfdP->fileName))
> - elog(LOG, "could not unlink file \"%s\": %m", vfdP->fileName);
> + ereport(LOG,
> + (errmsg("could not unlink file \"%s\": %m", vfdP->fileName)));

+1

>
> /* and last report the stat results */
> if (stat_errno == 0)
> @@ -1922,7 +1923,8 @@ FileClose(File file)
> else
> {
> errno = stat_errno;
> - elog(LOG, "could not stat file \"%s\": %m", vfdP->fileName);
> + ereport(LOG,
> + (errmsg("could not stat file \"%s\": %m", vfdP->fileName)));

+1

For the changes I didn't mention explicitly (most of them), I'm -0.5. Many of
them "can't happen", use source code terms of art, and/or breach guideline
"Avoid mentioning called function names, either; instead say what the code was
trying to do" (https://www.postgresql.org/docs/devel/error-style-guide.html).