diff options
Diffstat (limited to 'src/backend/commands')
| -rw-r--r-- | src/backend/commands/copy.c | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c index 6a5bba64ecb..e61384beec8 100644 --- a/src/backend/commands/copy.c +++ b/src/backend/commands/copy.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.274 2007/01/05 22:19:25 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.275 2007/01/25 02:17:26 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -1652,6 +1652,7 @@ CopyFrom(CopyState cstate) ExprContext *econtext; /* used for ExecEvalExpr for default atts */ MemoryContext oldcontext = CurrentMemoryContext; ErrorContextCallback errcontext; + bool use_wal = true; /* By default, we use WAL to log db changes */ Assert(cstate->rel); @@ -1843,6 +1844,28 @@ CopyFrom(CopyState cstate) nfields = file_has_oids ? (attr_count + 1) : attr_count; field_strings = (char **) palloc(nfields * sizeof(char *)); + /* + * Check for performance optimization by avoiding WAL writes + * + * If archive logging is not be enabled *and* either + * - table is created in same transaction as this COPY + * - table data is now being written to new relfilenode + * then we can safely avoid writing WAL. Why? + * The data files for the table plus toast table/index, plus any indexes + * will all be dropped at the end of the transaction if it fails, so we + * do not need to worry about inconsistent states. + * As mentioned in comments in utils/rel.h, the in-same-transaction test is + * not completely reliable, since rd_createSubId can be reset to zero in + * certain cases before the end of the creating transaction. + * We are doing this for performance only, so we only need to know: + * if rd_createSubid != InvalidSubTransactionId then it is *always* just + * created. If we have PITR enabled, then we *must* use_wal + */ + if ((cstate->rel->rd_createSubid != InvalidSubTransactionId || + cstate->rel->rd_newRelfilenodeSubid != InvalidSubTransactionId) + && !XLogArchivingActive()) + use_wal = false; + /* Initialize state variables */ cstate->fe_eof = false; cstate->eol_type = EOL_UNKNOWN; @@ -2076,7 +2099,7 @@ CopyFrom(CopyState cstate) ExecConstraints(resultRelInfo, slot, estate); /* OK, store the tuple and create index entries for it */ - simple_heap_insert(cstate->rel, tuple); + fast_heap_insert(cstate->rel, tuple, use_wal); if (resultRelInfo->ri_NumIndices > 0) ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false); @@ -2093,6 +2116,32 @@ CopyFrom(CopyState cstate) } } + /* + * If we skipped writing WAL for heaps, then we need to sync + */ + if (!use_wal) + { + /* main heap */ + heap_sync(cstate->rel); + + /* main heap indexes, if any */ + /* we always use WAL for index inserts, so no need to sync */ + + /* toast heap, if any */ + if (OidIsValid(cstate->rel->rd_rel->reltoastrelid)) + { + Relation toastrel; + + toastrel = heap_open(cstate->rel->rd_rel->reltoastrelid, + AccessShareLock); + heap_sync(toastrel); + heap_close(toastrel, AccessShareLock); + } + + /* toast index, if toast heap */ + /* we always use WAL for index inserts, so no need to sync */ + } + /* Done, clean up */ error_context_stack = errcontext.previous; |