Test IsInTransactionChain, not IsTransactionBlock, in vac_update_relstats.

As noted by Noah Misch, my initial cut at fixing bug #11638 didn't cover
all cases where ANALYZE might be invoked in an unsafe context.  We need to
test the result of IsInTransactionChain not IsTransactionBlock; which is
notationally a pain because IsInTransactionChain requires an isTopLevel
flag, which would have to be passed down through several levels of callers.
I chose to pass in_outer_xact (ie, the result of IsInTransactionChain)
rather than isTopLevel per se, as that seemed marginally more apropos
for the intermediate functions to know about.

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 376a57a1245d3313a544de859610d63966551984..62774a90fc034534544a29e3783d6115c331e769 100644 (file)
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -85,7 +85,7 @@ static BufferAccessStrategy vac_strategy;
 
 static void do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
                           AcquireSampleRowsFunc acquirefunc, BlockNumber relpages,
-                          bool inh, int elevel);
+                          bool inh, bool in_outer_xact, int elevel);
 static void BlockSampler_Init(BlockSampler bs, BlockNumber nblocks,
                                  int samplesize);
 static bool BlockSampler_HasMore(BlockSampler bs);
@@ -113,7 +113,8 @@ static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
  *     analyze_rel() -- analyze one relation
  */
 void
-analyze_rel(Oid relid, VacuumStmt *vacstmt, BufferAccessStrategy bstrategy)
+analyze_rel(Oid relid, VacuumStmt *vacstmt,
+                       bool in_outer_xact, BufferAccessStrategy bstrategy)
 {
        Relation        onerel;
        int                     elevel;
@@ -262,13 +263,15 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt, BufferAccessStrategy bstrategy)
        /*
         * Do the normal non-recursive ANALYZE.
         */
-       do_analyze_rel(onerel, vacstmt, acquirefunc, relpages, false, elevel);
+       do_analyze_rel(onerel, vacstmt, acquirefunc, relpages,
+                                  false, in_outer_xact, elevel);
 
        /*
         * If there are child tables, do recursive ANALYZE.
         */
        if (onerel->rd_rel->relhassubclass)
-               do_analyze_rel(onerel, vacstmt, acquirefunc, relpages, true, elevel);
+               do_analyze_rel(onerel, vacstmt, acquirefunc, relpages,
+                                          true, in_outer_xact, elevel);
 
        /*
         * Close source relation now, but keep lock so that no one deletes it
@@ -298,7 +301,7 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt, BufferAccessStrategy bstrategy)
 static void
 do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
                           AcquireSampleRowsFunc acquirefunc, BlockNumber relpages,
-                          bool inh, int elevel)
+                          bool inh, bool in_outer_xact, int elevel)
 {
        int                     attr_cnt,
                                tcnt,
@@ -580,7 +583,8 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
                                                        totalrows,
                                                        visibilitymap_count(onerel),
                                                        hasindex,
-                                                       InvalidTransactionId);
+                                                       InvalidTransactionId,
+                                                       in_outer_xact);
 
        /*
         * Same for indexes. Vacuum always scans all indexes, so if we're part of
@@ -600,7 +604,8 @@ do_analyze_rel(Relation onerel, VacuumStmt *vacstmt,
                                                                totalindexrows,
                                                                0,
                                                                false,
-                                                               InvalidTransactionId);
+                                                               InvalidTransactionId,
+                                                               in_outer_xact);
                }
        }
 

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 4e965b2ce0b4756d4e4d6a17483878a68f4f71c0..b9e7624134c69138586d2d744d4b9fe60c982f25 100644 (file)
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -199,6 +199,8 @@ vacuum(VacuumStmt *vacstmt, Oid relid, bool do_toast,
         */
        if (use_own_xacts)
        {
+               Assert(!in_outer_xact);
+
                /* ActiveSnapshot is not set by autovacuum */
                if (ActiveSnapshotSet())
                        PopActiveSnapshot();
@@ -244,7 +246,7 @@ vacuum(VacuumStmt *vacstmt, Oid relid, bool do_toast,
                                        PushActiveSnapshot(GetTransactionSnapshot());
                                }
 
-                               analyze_rel(relid, vacstmt, vac_strategy);
+                               analyze_rel(relid, vacstmt, in_outer_xact, vac_strategy);
 
                                if (use_own_xacts)
                                {
@@ -567,13 +569,13 @@ vac_estimate_reltuples(Relation relation, bool is_analyze,
  *             DDL flags such as relhasindex, by clearing them if no longer correct.
  *             It's safe to do this in VACUUM, which can't run in parallel with
  *             CREATE INDEX/RULE/TRIGGER and can't be part of a transaction block.
- *             However, it's *not* safe to do it in an ANALYZE that's within a
- *             transaction block, because for example the current transaction might
+ *             However, it's *not* safe to do it in an ANALYZE that's within an
+ *             outer transaction, because for example the current transaction might
  *             have dropped the last index; then we'd think relhasindex should be
  *             cleared, but if the transaction later rolls back this would be wrong.
- *             So we refrain from updating the DDL flags if we're inside a
- *             transaction block.  This is OK since postponing the flag maintenance
- *             is always allowable.
+ *             So we refrain from updating the DDL flags if we're inside an outer
+ *             transaction.  This is OK since postponing the flag maintenance is
+ *             always allowable.
  *
  *             This routine is shared by VACUUM and ANALYZE.
  */
@@ -581,7 +583,8 @@ void
 vac_update_relstats(Relation relation,
                                        BlockNumber num_pages, double num_tuples,
                                        BlockNumber num_all_visible_pages,
-                                       bool hasindex, TransactionId frozenxid)
+                                       bool hasindex, TransactionId frozenxid,
+                                       bool in_outer_xact)
 {
        Oid                     relid = RelationGetRelid(relation);
        Relation        rd;
@@ -617,9 +620,9 @@ vac_update_relstats(Relation relation,
                dirty = true;
        }
 
-       /* Apply DDL updates, but not inside a transaction block (see above) */
+       /* Apply DDL updates, but not inside an outer transaction (see above) */
 
-       if (!IsTransactionBlock())
+       if (!in_outer_xact)
        {
                /*
                 * If we didn't find any indexes, reset relhasindex.

diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index c4caa36f4b68c9d44593bb853d447b1a61f34d49..84d73b2676fd5f7cb4a038342f12d920b3719f79 100644 (file)
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -284,7 +284,8 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
                                                new_rel_tuples,
                                                new_rel_allvisible,
                                                vacrelstats->hasindex,
-                                               new_frozen_xid);
+                                               new_frozen_xid,
+                                               false);
 
        /* report results to the stats collector, too */
        pgstat_report_vacuum(RelationGetRelid(onerel),
@@ -1283,7 +1284,8 @@ lazy_cleanup_index(Relation indrel,
                                                        stats->num_index_tuples,
                                                        0,
                                                        false,
-                                                       InvalidTransactionId);
+                                                       InvalidTransactionId,
+                                                       false);
 
        ereport(elevel,
                        (errmsg("index \"%s\" now contains %.0f row versions in %u pages",

diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index 17411e623cf225e7db700bd20591b800ba90b649..b59ca8339fcbda9cdd44544d1710b6d4b67c2803 100644 (file)
--- a/src/include/commands/vacuum.h
+++ b/src/include/commands/vacuum.h
@@ -153,7 +153,8 @@ extern void vac_update_relstats(Relation relation,
                                        double num_tuples,
                                        BlockNumber num_all_visible_pages,
                                        bool hasindex,
-                                       TransactionId frozenxid);
+                                       TransactionId frozenxid,
+                                       bool in_outer_xact);
 extern void vacuum_set_xid_limits(int freeze_min_age, int freeze_table_age,
                                          bool sharedRel,
                                          TransactionId *oldestXmin,
@@ -168,7 +169,7 @@ extern void lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt,
 
 /* in commands/analyze.c */
 extern void analyze_rel(Oid relid, VacuumStmt *vacstmt,
-                       BufferAccessStrategy bstrategy);
+                       bool in_outer_xact, BufferAccessStrategy bstrategy);
 extern bool std_typanalyze(VacAttrStats *stats);
 extern double anl_random_fract(void);
 extern double anl_init_selection_state(int n);