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Clean up some dead code in pg_dump with tar format and gzip compression 

Compression with gzip has never been supported in the tar format of
pg_dump since this code has been introduced in c3e18804, as the use of
buffered I/O in gzdopen() changes the file positioning that tar
requires.  The original idea behind the use of compression with the tar
mode is to be able to include compressed data files (named %u.dat.gz)
and blob files (blob_%u.dat.gz) in the tarball generated by the dump,
with toc.dat, that tracks down if compression is used in the dump,
always uncompressed.

Note that this commit removes the dump part of the code as well as the
restore part, removing any dependency to zlib in pg_backup_tar.c.  There
could be an argument behind keeping around the restore part, but this
would require one to change the internals of a tarball previously dumped
so as data and blob files are compressed with toc.dat itself changed to
track down if compression is enabled.  However, the argument about
gzdopen() still holds in the read case with pg_restore.

Removing this code simplifies future additions related to compression in
pg_dump.

Author: Georgios Kokolatos, Rachel Heaton
Discussion: https://postgr.es/m/faUNEOpts9vunEaLnmxmG-DldLSg_ql137OC3JYDmgrOMHm1RvvWY2IdBkv_CRxm5spCCb_OmKNk2T03TMm0fBEWveFF9wA1WizPuAgB7Ss=@protonmail.com
This commit is contained in:
Michael Paquier 2022-03-31 10:34:10 +09:00
parent f8e0d900af
commit 8ac4c25a05
1 changed files with 11 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

89
src/bin/pg_dump/pg_backup_tar.c
View File

@ -65,11 +65,6 @@ static void _EndBlobs(ArchiveHandle *AH, TocEntry *te);
typedef struct
{
#ifdef HAVE_LIBZ
gzFile zFH;
#else
FILE *zFH;
#endif
FILE *nFH;
FILE *tarFH;
FILE *tmpFH;
@ -248,14 +243,7 @@ _ArchiveEntry(ArchiveHandle *AH, TocEntry *te)
ctx = (lclTocEntry *) pg_malloc0(sizeof(lclTocEntry));
if (te->dataDumper != NULL)
{
#ifdef HAVE_LIBZ
if (AH->compression == 0)
sprintf(fn, "%d.dat", te->dumpId);
else
sprintf(fn, "%d.dat.gz", te->dumpId);
#else
sprintf(fn, "%d.dat", te->dumpId);
#endif
snprintf(fn, sizeof(fn), "%d.dat", te->dumpId);
ctx->filename = pg_strdup(fn);
}
else
@ -320,10 +308,6 @@ tarOpen(ArchiveHandle *AH, const char *filename, char mode)
lclContext *ctx = (lclContext *) AH->formatData;
TAR_MEMBER *tm;
#ifdef HAVE_LIBZ
char fmode[14];
#endif
if (mode == 'r')
{
tm = _tarPositionTo(AH, filename);
@ -344,16 +328,10 @@ tarOpen(ArchiveHandle *AH, const char *filename, char mode)
}
}
#ifdef HAVE_LIBZ
if (AH->compression == 0)
tm->nFH = ctx->tarFH;
else
fatal("compression is not supported by tar archive format");
/* tm->zFH = gzdopen(dup(fileno(ctx->tarFH)), "rb"); */
#else
tm->nFH = ctx->tarFH;
#endif
}
else
{
@ -405,21 +383,10 @@ tarOpen(ArchiveHandle *AH, const char *filename, char mode)
umask(old_umask);
#ifdef HAVE_LIBZ
if (AH->compression != 0)
{
sprintf(fmode, "wb%d", AH->compression);
tm->zFH = gzdopen(dup(fileno(tm->tmpFH)), fmode);
if (tm->zFH == NULL)
fatal("could not open temporary file");
}
else
if (AH->compression == 0)
tm->nFH = tm->tmpFH;
#else
tm->nFH = tm->tmpFH;
#endif
else
fatal("compression is not supported by tar archive format");
tm->AH = AH;
tm->targetFile = pg_strdup(filename);
@ -434,15 +401,8 @@ tarOpen(ArchiveHandle *AH, const char *filename, char mode)
static void
tarClose(ArchiveHandle *AH, TAR_MEMBER *th)
{
/*
* Close the GZ file since we dup'd. This will flush the buffers.
*/
if (AH->compression != 0)
{
errno = 0; /* in case gzclose() doesn't set it */
if (GZCLOSE(th->zFH) != 0)
fatal("could not close tar member: %m");
}
fatal("compression is not supported by tar archive format");
if (th->mode == 'w')
_tarAddFile(AH, th); /* This will close the temp file */
@ -456,7 +416,6 @@ tarClose(ArchiveHandle *AH, TAR_MEMBER *th)
free(th->targetFile);
th->nFH = NULL;
th->zFH = NULL;
}
#ifdef __NOT_USED__
@ -542,29 +501,9 @@ _tarReadRaw(ArchiveHandle *AH, void *buf, size_t len, TAR_MEMBER *th, FILE *fh)
}
else if (th)
{
if (th->zFH)
{
res = GZREAD(&((char *) buf)[used], 1, len, th->zFH);
if (res != len && !GZEOF(th->zFH))
{
#ifdef HAVE_LIBZ
int errnum;
const char *errmsg = gzerror(th->zFH, &errnum);
fatal("could not read from input file: %s",
errnum == Z_ERRNO ? strerror(errno) : errmsg);
#else
fatal("could not read from input file: %s",
strerror(errno));
#endif
}
}
else
{
res = fread(&((char *) buf)[used], 1, len, th->nFH);
if (res != len && !feof(th->nFH))
READ_ERROR_EXIT(th->nFH);
}
res = fread(&((char *) buf)[used], 1, len, th->nFH);
if (res != len && !feof(th->nFH))
READ_ERROR_EXIT(th->nFH);
}
}
@ -596,10 +535,7 @@ tarWrite(const void *buf, size_t len, TAR_MEMBER *th)
{
size_t res;
if (th->zFH != NULL)
res = GZWRITE(buf, 1, len, th->zFH);
else
res = fwrite(buf, 1, len, th->nFH);
res = fwrite(buf, 1, len, th->nFH);
th->pos += res;
return res;
@ -949,17 +885,14 @@ _StartBlob(ArchiveHandle *AH, TocEntry *te, Oid oid)
lclContext *ctx = (lclContext *) AH->formatData;
lclTocEntry *tctx = (lclTocEntry *) te->formatData;
char fname[255];
char *sfx;
if (oid == 0)
fatal("invalid OID for large object (%u)", oid);
if (AH->compression != 0)
sfx = ".gz";
else
sfx = "";
fatal("compression is not supported by tar archive format");
sprintf(fname, "blob_%u.dat%s", oid, sfx);
sprintf(fname, "blob_%u.dat", oid);
tarPrintf(ctx->blobToc, "%u %s\n", oid, fname);