From d89cbae1851627be4e146efedc92ba9d0a67ad6a Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Sun, 30 Apr 2023 11:10:08 +1200 Subject: [PATCH 07/11] Use copy_file_range() to implement copy_file(). If copy_file_range() is available, use it to implement copy_file(), so that the operating system has opportunities for efficient copying, block cloning and pushdown. This affects the commands CREATE DATABASE STRATEGY=FILE_COPY and ALTER TABLE SET TABLESPACE, which perform bulk file copies. On older Linux systems, copy_file_range() might fail with EXDEV, so we look out for that and fall back to the traditional read/write loop. XXX Should we also let the user opt out? --- doc/src/sgml/monitoring.sgml | 4 ++ src/backend/storage/file/copydir.c | 94 +++++++++++++++++++------ src/backend/utils/activity/wait_event.c | 3 + src/include/utils/wait_event.h | 1 + 4 files changed, 82 insertions(+), 20 deletions(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 99f7f95c39..2161b32b17 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -1317,6 +1317,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser Waiting for a write to update the pg_control file. + + CopyFileRange + Waiting for range to be copied during a file copy operation. + CopyFileRead Waiting for a read during a file copy operation. diff --git a/src/backend/storage/file/copydir.c b/src/backend/storage/file/copydir.c index 82f77536b4..497d357d8c 100644 --- a/src/backend/storage/file/copydir.c +++ b/src/backend/storage/file/copydir.c @@ -126,6 +126,14 @@ copy_file(const char *fromfile, const char *tofile) /* Size of copy buffer (read and write requests) */ #define COPY_BUF_SIZE (8 * BLCKSZ) + /* + * Size of ranges when using copy_file_range(). We could in theory just + * use the whole file size, but we want to check for interrupts + * periodically while copying. We don't want to make it too small though, + * to give the operating system the chance to clone large extents. + */ +#define COPY_FILE_RANGE_CHUNK_SIZE (1024 * 1024) + /* * Size of data flush requests. It seems beneficial on most platforms to * do this every 1MB or so. But macOS, at least with early releases of @@ -138,8 +146,13 @@ copy_file(const char *fromfile, const char *tofile) #define FLUSH_DISTANCE (1024 * 1024) #endif +#ifdef HAVE_COPY_FILE_RANGE + /* Don't allocate the buffer unless we have to fall back to read/write. */ + buffer = NULL; +#else /* Use palloc to ensure we get a maxaligned buffer */ buffer = palloc(COPY_BUF_SIZE); +#endif /* * Open the files @@ -176,27 +189,67 @@ copy_file(const char *fromfile, const char *tofile) flush_offset = offset; } - pgstat_report_wait_start(WAIT_EVENT_COPY_FILE_READ); - nbytes = read(srcfd, buffer, COPY_BUF_SIZE); - pgstat_report_wait_end(); - if (nbytes < 0) - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not read file \"%s\": %m", fromfile))); - if (nbytes == 0) - break; - errno = 0; - pgstat_report_wait_start(WAIT_EVENT_COPY_FILE_WRITE); - if ((int) write(dstfd, buffer, nbytes) != nbytes) + nbytes = 0; /* silence compiler */ + +#ifdef HAVE_COPY_FILE_RANGE + if (buffer == NULL) + { + pgstat_report_wait_start(WAIT_EVENT_COPY_FILE_RANGE); + nbytes = copy_file_range(srcfd, NULL, dstfd, NULL, + COPY_FILE_RANGE_CHUNK_SIZE, 0); + pgstat_report_wait_end(); + + if (nbytes < 0) + { + if (errno == EXDEV) + { + /* + * Linux < 5.3 fails like this for cross-filesystem copies. + * Allocate the buffer to fall back to read/write mode. + */ + buffer = palloc(COPY_BUF_SIZE); + } + else + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not copy to file \"%s\": %m", tofile))); + } + } +#endif + + if (buffer) { - /* if write didn't set errno, assume problem is no disk space */ - if (errno == 0) - errno = ENOSPC; - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not write to file \"%s\": %m", tofile))); + pgstat_report_wait_start(WAIT_EVENT_COPY_FILE_READ); + nbytes = read(srcfd, buffer, COPY_BUF_SIZE); + pgstat_report_wait_end(); + + if (nbytes < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", fromfile))); + + if (nbytes > 0) + { + errno = 0; + pgstat_report_wait_start(WAIT_EVENT_COPY_FILE_WRITE); + if ((int) write(dstfd, buffer, nbytes) != nbytes) + { + /* + * If write didn't set errno, assume problem is no disk + * space. + */ + if (errno == 0) + errno = ENOSPC; + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not write to file \"%s\": %m", tofile))); + } + pgstat_report_wait_end(); + } } - pgstat_report_wait_end(); + + if (nbytes == 0) + break; } if (offset > flush_offset) @@ -212,5 +265,6 @@ copy_file(const char *fromfile, const char *tofile) (errcode_for_file_access(), errmsg("could not close file \"%s\": %m", fromfile))); - pfree(buffer); + if (buffer) + pfree(buffer); } diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.c index 7940d64639..9c3cd088c0 100644 --- a/src/backend/utils/activity/wait_event.c +++ b/src/backend/utils/activity/wait_event.c @@ -567,6 +567,9 @@ pgstat_get_wait_io(WaitEventIO w) case WAIT_EVENT_CONTROL_FILE_WRITE_UPDATE: event_name = "ControlFileWriteUpdate"; break; + case WAIT_EVENT_COPY_FILE_RANGE: + event_name = "CopyFileRange"; + break; case WAIT_EVENT_COPY_FILE_READ: event_name = "CopyFileRead"; break; diff --git a/src/include/utils/wait_event.h b/src/include/utils/wait_event.h index 518d3b0a1f..517de1544b 100644 --- a/src/include/utils/wait_event.h +++ b/src/include/utils/wait_event.h @@ -172,6 +172,7 @@ typedef enum WAIT_EVENT_CONTROL_FILE_SYNC_UPDATE, WAIT_EVENT_CONTROL_FILE_WRITE, WAIT_EVENT_CONTROL_FILE_WRITE_UPDATE, + WAIT_EVENT_COPY_FILE_RANGE, WAIT_EVENT_COPY_FILE_READ, WAIT_EVENT_COPY_FILE_WRITE, WAIT_EVENT_DATA_FILE_EXTEND, -- 2.40.1