From 4e361bfe51810d7c637bf57968da2dfea4197701 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Fri, 17 May 2019 16:01:47 -0400 Subject: [PATCH v2] tableam: Move heap-specific logic from needs_toast_table below tableam. This allows table AMs to completely suppress TOAST table creation, or to modify the conditions under which they are created. Patch by me. Reviewed by Andres Freund. Discussion: http://postgr.es/m/CALfoeitE+P8UGii8=BsGQLpHch2EZWJhq4M+D-jfaj8YCa_FSw@mail.gmail.com --- src/backend/access/heap/heapam_handler.c | 53 ++++++++++++++++++++++++ src/backend/catalog/toasting.c | 50 ++-------------------- src/include/access/tableam.h | 20 +++++++++ 3 files changed, 76 insertions(+), 47 deletions(-) diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index 8d8161fd97..56b2abda5f 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -29,6 +29,7 @@ #include "access/rewriteheap.h" #include "access/tableam.h" #include "access/tsmapi.h" +#include "access/tuptoaster.h" #include "access/xact.h" #include "catalog/catalog.h" #include "catalog/index.h" @@ -2009,6 +2010,57 @@ heapam_relation_size(Relation rel, ForkNumber forkNumber) return nblocks * BLCKSZ; } +/* + * Check to see whether the table needs a TOAST table. It does only if + * (1) there are any toastable attributes, and (2) the maximum length + * of a tuple could exceed TOAST_TUPLE_THRESHOLD. (We don't want to + * create a toast table for something like "f1 varchar(20)".) + */ +static bool +heapam_relation_needs_toast_table(Relation rel) +{ + int32 data_length = 0; + bool maxlength_unknown = false; + bool has_toastable_attrs = false; + TupleDesc tupdesc = rel->rd_att; + int32 tuple_length; + int i; + + for (i = 0; i < tupdesc->natts; i++) + { + Form_pg_attribute att = TupleDescAttr(tupdesc, i); + + if (att->attisdropped) + continue; + data_length = att_align_nominal(data_length, att->attalign); + if (att->attlen > 0) + { + /* Fixed-length types are never toastable */ + data_length += att->attlen; + } + else + { + int32 maxlen = type_maximum_size(att->atttypid, + att->atttypmod); + + if (maxlen < 0) + maxlength_unknown = true; + else + data_length += maxlen; + if (att->attstorage != 'p') + has_toastable_attrs = true; + } + } + if (!has_toastable_attrs) + return false; /* nothing to toast? */ + if (maxlength_unknown) + return true; /* any unlimited-length attrs? */ + tuple_length = MAXALIGN(SizeofHeapTupleHeader + + BITMAPLEN(tupdesc->natts)) + + MAXALIGN(data_length); + return (tuple_length > TOAST_TUPLE_THRESHOLD); +} + /* ------------------------------------------------------------------------ * Planner related callbacks for the heap AM @@ -2592,6 +2644,7 @@ static const TableAmRoutine heapam_methods = { .index_validate_scan = heapam_index_validate_scan, .relation_size = heapam_relation_size, + .relation_needs_toast_table = heapam_relation_needs_toast_table, .relation_estimate_size = heapam_estimate_rel_size, diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c index 2276d3c5d3..cf20ddb4e9 100644 --- a/src/backend/catalog/toasting.c +++ b/src/backend/catalog/toasting.c @@ -15,7 +15,6 @@ #include "postgres.h" #include "access/heapam.h" -#include "access/tuptoaster.h" #include "access/xact.h" #include "catalog/binary_upgrade.h" #include "catalog/catalog.h" @@ -386,21 +385,11 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid, } /* - * Check to see whether the table needs a TOAST table. It does only if - * (1) there are any toastable attributes, and (2) the maximum length - * of a tuple could exceed TOAST_TUPLE_THRESHOLD. (We don't want to - * create a toast table for something like "f1 varchar(20)".) + * Check to see whether the table needs a TOAST table. */ static bool needs_toast_table(Relation rel) { - int32 data_length = 0; - bool maxlength_unknown = false; - bool has_toastable_attrs = false; - TupleDesc tupdesc; - int32 tuple_length; - int i; - /* * No need to create a TOAST table for partitioned tables. */ @@ -423,39 +412,6 @@ needs_toast_table(Relation rel) if (IsCatalogRelation(rel) && !IsBootstrapProcessingMode()) return false; - tupdesc = rel->rd_att; - - for (i = 0; i < tupdesc->natts; i++) - { - Form_pg_attribute att = TupleDescAttr(tupdesc, i); - - if (att->attisdropped) - continue; - data_length = att_align_nominal(data_length, att->attalign); - if (att->attlen > 0) - { - /* Fixed-length types are never toastable */ - data_length += att->attlen; - } - else - { - int32 maxlen = type_maximum_size(att->atttypid, - att->atttypmod); - - if (maxlen < 0) - maxlength_unknown = true; - else - data_length += maxlen; - if (att->attstorage != 'p') - has_toastable_attrs = true; - } - } - if (!has_toastable_attrs) - return false; /* nothing to toast? */ - if (maxlength_unknown) - return true; /* any unlimited-length attrs? */ - tuple_length = MAXALIGN(SizeofHeapTupleHeader + - BITMAPLEN(tupdesc->natts)) + - MAXALIGN(data_length); - return (tuple_length > TOAST_TUPLE_THRESHOLD); + /* Otherwise, let the AM decide. */ + return table_relation_needs_toast_table(rel); } diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h index 06eae2337a..53b58c51da 100644 --- a/src/include/access/tableam.h +++ b/src/include/access/tableam.h @@ -573,6 +573,16 @@ typedef struct TableAmRoutine uint64 (*relation_size) (Relation rel, ForkNumber forkNumber); + /* + * This callback should return true if the relation requires a TOAST table + * and false if it does not. It may wish to examine the relation's + * tuple descriptor before making a decision, but if it uses some other + * method of storing large values (or if it does not support them) it can + * simply return false. + */ + bool (*relation_needs_toast_table) (Relation rel); + + /* ------------------------------------------------------------------------ * Planner related functions. * ------------------------------------------------------------------------ @@ -1585,6 +1595,16 @@ table_relation_size(Relation rel, ForkNumber forkNumber) return rel->rd_tableam->relation_size(rel, forkNumber); } +/* + * table_needs_toast_table - does this relation need a toast table? + */ +static inline bool +table_relation_needs_toast_table(Relation rel) +{ + return rel->rd_tableam->relation_needs_toast_table(rel); +} + + /* ---------------------------------------------------------------------------- * Planner related functionality * ---------------------------------------------------------------------------- -- 2.17.2 (Apple Git-113)