diff --git a/src/bin/pg_rewind/filemap.c b/src/bin/pg_rewind/filemap.c index 435742d20d..a2e2110fb1 100644 --- a/src/bin/pg_rewind/filemap.c +++ b/src/bin/pg_rewind/filemap.c @@ -39,14 +39,14 @@ * appearing in source and target systems. */ static uint32 hash_string_pointer(const char *s); -#define SH_PREFIX filehash -#define SH_ELEMENT_TYPE file_entry_t -#define SH_KEY_TYPE const char * -#define SH_KEY path +#define SH_PREFIX filehash +#define SH_ELEMENT_TYPE file_entry_t +#define SH_KEY_TYPE const char * +#define SH_KEY path #define SH_HASH_KEY(tb, key) hash_string_pointer(key) #define SH_EQUAL(tb, a, b) (strcmp(a, b) == 0) -#define SH_SCOPE static inline -#define SH_RAW_ALLOCATOR pg_malloc0 +#define SH_SCOPE static inline +#define SH_RAW_ALLOCATOR pg_malloc0 #define SH_DECLARE #define SH_DEFINE #include "lib/simplehash.h" @@ -61,7 +61,36 @@ static char *datasegpath(RelFileLocator rlocator, ForkNumber forknum, static file_entry_t *insert_filehash_entry(const char *path); static file_entry_t *lookup_filehash_entry(const char *path); + +/* + * A separate hash table which tracks WAL files that must not be deleted. + */ +typedef struct keepwal_entry +{ + const char *path; + uint32 status; +} keepwal_entry; + +#define SH_PREFIX keepwal +#define SH_ELEMENT_TYPE keepwal_entry +#define SH_KEY_TYPE const char * +#define SH_KEY path +#define SH_HASH_KEY(tb, key) hash_string_pointer(key) +#define SH_EQUAL(tb, a, b) (strcmp(a, b) == 0) +#define SH_SCOPE static inline +#define SH_RAW_ALLOCATOR pg_malloc0 +#define SH_DECLARE +#define SH_DEFINE +#include "lib/simplehash.h" + +#define KEEPWAL_INITIAL_SIZE 1000 + + +static keepwal_hash *keepwal = NULL; +static bool keepwal_entry_exists(const char *path); + static int final_filemap_cmp(const void *a, const void *b); + static bool check_file_excluded(const char *path, bool is_source); /* @@ -207,6 +236,39 @@ lookup_filehash_entry(const char *path) return filehash_lookup(filehash, path); } +/* + * Initialize a hash table to store WAL file names that must be kept. + */ +void +keepwal_init(void) +{ + /* An initial hash size out of thin air */ + keepwal = keepwal_create(KEEPWAL_INITIAL_SIZE, NULL); +} + +/* Mark the given file to prevent its removal */ +void +keepwal_add_entry(const char *path) +{ + keepwal_entry *entry; + bool found; + + /* Should only be called with keepwal initialized */ + Assert(keepwal != NULL); + + entry = keepwal_insert(keepwal, path, &found); + + if (!found) + entry->path = pg_strdup(path); +} + +/* Return true if file is marked as not to be removed, false otherwise */ +static bool +keepwal_entry_exists(const char *path) +{ + return keepwal_lookup(keepwal, path) != NULL; +} + /* * Callback for processing source file list. * @@ -686,7 +748,15 @@ decide_file_action(file_entry_t *entry) } else if (entry->target_exists && !entry->source_exists) { - /* File exists in target, but not source. Remove it. */ + /* + * For files that exist in target but not in source, we check the + * keepwal hash table; any files listed therein must not be removed. + */ + if (keepwal_entry_exists(path)) + { + pg_log_debug("Not removing file \"%s\" because it is required for recovery", path); + return FILE_ACTION_NONE; + } return FILE_ACTION_REMOVE; } else if (!entry->target_exists && !entry->source_exists) diff --git a/src/bin/pg_rewind/filemap.h b/src/bin/pg_rewind/filemap.h index 48f240dff1..289ae9cab6 100644 --- a/src/bin/pg_rewind/filemap.h +++ b/src/bin/pg_rewind/filemap.h @@ -110,4 +110,7 @@ extern filemap_t *decide_file_actions(void); extern void calculate_totals(filemap_t *filemap); extern void print_filemap(filemap_t *filemap); +extern void keepwal_init(void); +extern void keepwal_add_entry(const char *path); + #endif /* FILEMAP_H */ diff --git a/src/bin/pg_rewind/meson.build b/src/bin/pg_rewind/meson.build index fd22818be4..880346f37b 100644 --- a/src/bin/pg_rewind/meson.build +++ b/src/bin/pg_rewind/meson.build @@ -43,6 +43,7 @@ tests += { 't/007_standby_source.pl', 't/008_min_recovery_point.pl', 't/009_growing_files.pl', + 't/010_keep_recycled_wals.pl', ], }, } diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c index 27782237d0..0ed0884152 100644 --- a/src/bin/pg_rewind/parsexlog.c +++ b/src/bin/pg_rewind/parsexlog.c @@ -175,6 +175,8 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, XLogReaderState *xlogreader; char *errormsg; XLogPageReadPrivate private; + XLogSegNo current_segno = 0; + TimeLineID current_tli = 0; /* * The given fork pointer points to the end of the last common record, @@ -217,6 +219,25 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, int tliIndex, LSN_FORMAT_ARGS(searchptr)); } + /* Detect if a new WAL file has been opened */ + if (xlogreader->seg.ws_tli != current_tli || + xlogreader->seg.ws_segno != current_segno) + { + char xlogfname[MAXFNAMELEN]; + + snprintf(xlogfname, MAXFNAMELEN, XLOGDIR "/"); + + /* update curent values */ + current_tli = xlogreader->seg.ws_tli; + current_segno = xlogreader->seg.ws_segno; + + XLogFileName(xlogfname + sizeof(XLOGDIR), + current_tli, current_segno, WalSegSz); + + /* Track this filename as one to not remove */ + keepwal_add_entry(xlogfname); + } + /* * Check if it is a checkpoint record. This checkpoint record needs to * be the latest checkpoint before WAL forked and not the checkpoint diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c index 53110e0f4b..c2c0f0b9f2 100644 --- a/src/bin/pg_rewind/pg_rewind.c +++ b/src/bin/pg_rewind/pg_rewind.c @@ -446,6 +446,9 @@ main(int argc, char **argv) exit(0); } + /* Initialize hashtable that tracks WAL files protected from removal */ + keepwal_init(); + findLastCheckpoint(datadir_target, divergerec, lastcommontliIndex, &chkptrec, &chkpttli, &chkptredo, restore_command); pg_log_info("rewinding from last common checkpoint at %X/%X on timeline %u", diff --git a/src/bin/pg_rewind/t/010_keep_recycled_wals.pl b/src/bin/pg_rewind/t/010_keep_recycled_wals.pl new file mode 100644 index 0000000000..e6dfce2a54 --- /dev/null +++ b/src/bin/pg_rewind/t/010_keep_recycled_wals.pl @@ -0,0 +1,62 @@ +# Copyright (c) 2021-2024, PostgreSQL Global Development Group +# +# Test situation where a target data directory contains +# WAL files that were already recycled by the new primary. +# + +use strict; +use warnings FATAL => 'all'; +use PostgreSQL::Test::Utils; +use Test::More; + +use FindBin; +use lib $FindBin::RealBin; +use RewindTest; + +RewindTest::setup_cluster(); +$node_primary->enable_archiving(); +RewindTest::start_primary(); + +RewindTest::create_standby(); +$node_standby->enable_restoring($node_primary, 0); +$node_standby->reload(); + +RewindTest::primary_psql("CHECKPOINT"); # last common checkpoint + +# We use "perl -e 'exit(1)'" as an alternative to "false", because the latter +# might not be available on Windows. +my $false = "$^X -e 'exit(1)'"; +$node_primary->append_conf( + 'postgresql.conf', qq( +archive_command = '$false' +)); +$node_primary->reload(); + +# advance WAL on primary; this WAL segment will never make it to the archive +RewindTest::primary_psql("CREATE TABLE t(a int)"); +RewindTest::primary_psql("INSERT INTO t VALUES(0)"); +RewindTest::primary_psql("SELECT pg_switch_wal()"); + +RewindTest::promote_standby; + +# new primary loses diverging WAL segment +RewindTest::standby_psql("INSERT INTO t values(0)"); +RewindTest::standby_psql("SELECT pg_switch_wal()"); + +$node_standby->stop(); +$node_primary->stop(); + +my ($stdout, $stderr) = run_command( + [ + 'pg_rewind', '--debug', + '--source-pgdata', $node_standby->data_dir, + '--target-pgdata', $node_primary->data_dir, + '--no-sync', + ]); + +like( + $stderr, + qr/Not removing file .* because it is required for recovery/, + "some WAL files were skipped"); + +done_testing(); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index d48f424fe6..a21c039c5b 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -3430,6 +3430,8 @@ json_manifest_perwalrange_callback json_ofield_action json_scalar_action json_struct_action +keepwal_entry +keepwal_hash keyEntryData key_t lclContext