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Don't try to print data type names in slot_store_error_callback(). 

The existing code tried to do syscache lookups in an already-failed
transaction, which is problematic to say the least.  After some
consideration of alternatives, the best fix seems to be to just drop
type names from the error message altogether.  The table and column
names seem like sufficient localization.  If the user is unsure what
types are involved, she can check the local and remote table
definitions.

Having done that, we can also discard the LogicalRepTypMap hash
table, which had no other use.  Arguably, LOGICAL_REP_MSG_TYPE
replication messages are now obsolete as well; but we should
probably keep them in case some other use emerges.  (The complexity
of removing something from the replication protocol would likely
outweigh any savings anyhow.)

Masahiko Sawada and Bharath Rupireddy, per complaint from Andres
Freund.  Back-patch to v10 where this code originated.

Discussion: https://postgr.es/m/20210106020229.ne5xnuu6wlondjpe@alap3.anarazel.de
This commit is contained in:
Tom Lane 2021-07-02 16:04:54 -04:00
parent 6bd3ec62d9
commit 50371df266
3 changed files with 6 additions and 134 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

105
src/backend/replication/logical/relation.c
View File

@ -17,7 +17,6 @@
#include "postgres.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/namespace.h"
#include "catalog/pg_subscription_rel.h"
@ -25,16 +24,12 @@
#include "nodes/makefuncs.h"
#include "replication/logicalrelation.h"
#include "replication/worker_internal.h"
#include "utils/builtins.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
static MemoryContext LogicalRepRelMapContext = NULL;
static HTAB *LogicalRepRelMap = NULL;
static HTAB *LogicalRepTypMap = NULL;
/*
* Partition map (LogicalRepPartMap)
@ -118,15 +113,6 @@ logicalrep_relmap_init(void)
LogicalRepRelMap = hash_create("logicalrep relation map cache", 128, &ctl,
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
/* Initialize the type hash table. */
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(LogicalRepTyp);
ctl.hcxt = LogicalRepRelMapContext;
/* This will usually be small. */
LogicalRepTypMap = hash_create("logicalrep type map cache", 2, &ctl,
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
/* Watch for invalidation events. */
CacheRegisterRelcacheCallback(logicalrep_relmap_invalidate_cb,
(Datum) 0);
@ -450,95 +436,6 @@ logicalrep_rel_close(LogicalRepRelMapEntry *rel, LOCKMODE lockmode)
rel->localrel = NULL;
}
/*
* Free the type map cache entry data.
*/
static void
logicalrep_typmap_free_entry(LogicalRepTyp *entry)
{
pfree(entry->nspname);
pfree(entry->typname);
}
/*
* Add new entry or update existing entry in the type map cache.
*/
void
logicalrep_typmap_update(LogicalRepTyp *remotetyp)
{
MemoryContext oldctx;
LogicalRepTyp *entry;
bool found;
if (LogicalRepTypMap == NULL)
logicalrep_relmap_init();
/*
* HASH_ENTER returns the existing entry if present or creates a new one.
*/
entry = hash_search(LogicalRepTypMap, (void *) &remotetyp->remoteid,
HASH_ENTER, &found);
if (found)
logicalrep_typmap_free_entry(entry);
/* Make cached copy of the data */
entry->remoteid = remotetyp->remoteid;
oldctx = MemoryContextSwitchTo(LogicalRepRelMapContext);
entry->nspname = pstrdup(remotetyp->nspname);
entry->typname = pstrdup(remotetyp->typname);
MemoryContextSwitchTo(oldctx);
}
/*
* Fetch type name from the cache by remote type OID.
*
* Return a substitute value if we cannot find the data type; no message is
* sent to the log in that case, because this is used by error callback
* already.
*/
char *
logicalrep_typmap_gettypname(Oid remoteid)
{
LogicalRepTyp *entry;
bool found;
/* Internal types are mapped directly. */
if (remoteid < FirstGenbkiObjectId)
{
if (!get_typisdefined(remoteid))
{
/*
* This can be caused by having a publisher with a higher
* PostgreSQL major version than the subscriber.
*/
return psprintf("unrecognized %u", remoteid);
}
return format_type_be(remoteid);
}
if (LogicalRepTypMap == NULL)
{
/*
* If the typemap is not initialized yet, we cannot possibly attempt
* to search the hash table; but there's no way we know the type
* locally yet, since we haven't received a message about this type,
* so this is the best we can do.
*/
return psprintf("unrecognized %u", remoteid);
}
/* search the mapping */
entry = hash_search(LogicalRepTypMap, (void *) &remoteid,
HASH_FIND, &found);
if (!found)
return psprintf("unrecognized %u", remoteid);
Assert(OidIsValid(entry->remoteid));
return psprintf("%s.%s", entry->nspname, entry->typname);
}
/*
* Partition cache: look up partition LogicalRepRelMapEntry's
*

32
src/backend/replication/logical/worker.c
View File

@ -132,7 +132,6 @@ static dlist_head lsn_mapping = DLIST_STATIC_INIT(lsn_mapping);
typedef struct SlotErrCallbackArg
{
LogicalRepRelMapEntry *rel;
int local_attnum;
int remote_attnum;
} SlotErrCallbackArg;
@ -503,36 +502,23 @@ slot_fill_defaults(LogicalRepRelMapEntry *rel, EState *estate,
}
/*
* Error callback to give more context info about type conversion failure.
* Error callback to give more context info about data conversion failures
* while reading data from the remote server.
*/
static void
slot_store_error_callback(void *arg)
{
SlotErrCallbackArg *errarg = (SlotErrCallbackArg *) arg;
LogicalRepRelMapEntry *rel;
char *remotetypname;
Oid remotetypoid,
localtypoid;
/* Nothing to do if remote attribute number is not set */
if (errarg->remote_attnum < 0)
return;
rel = errarg->rel;
remotetypoid = rel->remoterel.atttyps[errarg->remote_attnum];
/* Fetch remote type name from the LogicalRepTypMap cache */
remotetypname = logicalrep_typmap_gettypname(remotetypoid);
/* Fetch local type OID from the local sys cache */
localtypoid = get_atttype(rel->localreloid, errarg->local_attnum + 1);
errcontext("processing remote data for replication target relation \"%s.%s\" column \"%s\", "
"remote type %s, local type %s",
errcontext("processing remote data for replication target relation \"%s.%s\" column \"%s\"",
rel->remoterel.nspname, rel->remoterel.relname,
rel->remoterel.attnames[errarg->remote_attnum],
remotetypname,
format_type_be(localtypoid));
rel->remoterel.attnames[errarg->remote_attnum]);
}
/*
@ -553,7 +539,6 @@ slot_store_data(TupleTableSlot *slot, LogicalRepRelMapEntry *rel,
/* Push callback + info on the error context stack */
errarg.rel = rel;
errarg.local_attnum = -1;
errarg.remote_attnum = -1;
errcallback.callback = slot_store_error_callback;
errcallback.arg = (void *) &errarg;
@ -573,7 +558,6 @@ slot_store_data(TupleTableSlot *slot, LogicalRepRelMapEntry *rel,
Assert(remoteattnum < tupleData->ncols);
errarg.local_attnum = i;
errarg.remote_attnum = remoteattnum;
if (tupleData->colstatus[remoteattnum] == LOGICALREP_COLUMN_TEXT)
@ -622,7 +606,6 @@ slot_store_data(TupleTableSlot *slot, LogicalRepRelMapEntry *rel,
slot->tts_isnull[i] = true;
}
errarg.local_attnum = -1;
errarg.remote_attnum = -1;
}
else
@ -679,7 +662,6 @@ slot_modify_data(TupleTableSlot *slot, TupleTableSlot *srcslot,
/* For error reporting, push callback + info on the error context stack */
errarg.rel = rel;
errarg.local_attnum = -1;
errarg.remote_attnum = -1;
errcallback.callback = slot_store_error_callback;
errcallback.arg = (void *) &errarg;
@ -702,7 +684,6 @@ slot_modify_data(TupleTableSlot *slot, TupleTableSlot *srcslot,
{
StringInfo colvalue = &tupleData->colvalues[remoteattnum];
errarg.local_attnum = i;
errarg.remote_attnum = remoteattnum;
if (tupleData->colstatus[remoteattnum] == LOGICALREP_COLUMN_TEXT)
@ -747,7 +728,6 @@ slot_modify_data(TupleTableSlot *slot, TupleTableSlot *srcslot,
slot->tts_isnull[i] = true;
}
errarg.local_attnum = -1;
errarg.remote_attnum = -1;
}
}
@ -1217,8 +1197,7 @@ apply_handle_relation(StringInfo s)
/*
* Handle TYPE message.
*
* Note we don't do local mapping here, that's done when the type is
* actually used.
* This is now vestigial; we read the info and discard it.
*/
static void
apply_handle_type(StringInfo s)
@ -1229,7 +1208,6 @@ apply_handle_type(StringInfo s)
return;
logicalrep_read_typ(s, &typ);
logicalrep_typmap_update(&typ);
}
/*

3
src/include/replication/logicalrelation.h
View File

@ -46,7 +46,4 @@ extern LogicalRepRelMapEntry *logicalrep_partition_open(LogicalRepRelMapEntry *r
extern void logicalrep_rel_close(LogicalRepRelMapEntry *rel,
LOCKMODE lockmode);
extern void logicalrep_typmap_update(LogicalRepTyp *remotetyp);
extern char *logicalrep_typmap_gettypname(Oid remoteid);
#endif /* LOGICALRELATION_H */