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Diffstat (limited to 'src/backend/access/heap/tuptoaster.c')
| -rw-r--r-- | src/backend/access/heap/tuptoaster.c | 2419 |
1 files changed, 0 insertions, 2419 deletions
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c deleted file mode 100644 index 970e78d8499..00000000000 --- a/src/backend/access/heap/tuptoaster.c +++ /dev/null @@ -1,2419 +0,0 @@ -/*------------------------------------------------------------------------- - * - * tuptoaster.c - * Support routines for external and compressed storage of - * variable size attributes. - * - * Copyright (c) 2000-2019, PostgreSQL Global Development Group - * - * - * IDENTIFICATION - * src/backend/access/heap/tuptoaster.c - * - * - * INTERFACE ROUTINES - * toast_insert_or_update - - * Try to make a given tuple fit into one page by compressing - * or moving off attributes - * - * toast_delete - - * Reclaim toast storage when a tuple is deleted - * - * heap_tuple_untoast_attr - - * Fetch back a given value from the "secondary" relation - * - *------------------------------------------------------------------------- - */ - -#include "postgres.h" - -#include <unistd.h> -#include <fcntl.h> - -#include "access/genam.h" -#include "access/heapam.h" -#include "access/tuptoaster.h" -#include "access/xact.h" -#include "catalog/catalog.h" -#include "common/pg_lzcompress.h" -#include "miscadmin.h" -#include "utils/expandeddatum.h" -#include "utils/fmgroids.h" -#include "utils/rel.h" -#include "utils/snapmgr.h" -#include "utils/typcache.h" - - -/* - * The information at the start of the compressed toast data. - */ -typedef struct toast_compress_header -{ - int32 vl_len_; /* varlena header (do not touch directly!) */ - int32 rawsize; -} toast_compress_header; - -/* - * Utilities for manipulation of header information for compressed - * toast entries. - */ -#define TOAST_COMPRESS_HDRSZ ((int32) sizeof(toast_compress_header)) -#define TOAST_COMPRESS_RAWSIZE(ptr) (((toast_compress_header *) (ptr))->rawsize) -#define TOAST_COMPRESS_RAWDATA(ptr) \ - (((char *) (ptr)) + TOAST_COMPRESS_HDRSZ) -#define TOAST_COMPRESS_SET_RAWSIZE(ptr, len) \ - (((toast_compress_header *) (ptr))->rawsize = (len)) - -static void toast_delete_datum(Relation rel, Datum value, bool is_speculative); -static Datum toast_save_datum(Relation rel, Datum value, - struct varlena *oldexternal, int options); -static bool toastrel_valueid_exists(Relation toastrel, Oid valueid); -static bool toastid_valueid_exists(Oid toastrelid, Oid valueid); -static struct varlena *toast_fetch_datum(struct varlena *attr); -static struct varlena *toast_fetch_datum_slice(struct varlena *attr, - int32 sliceoffset, int32 length); -static struct varlena *toast_decompress_datum(struct varlena *attr); -static struct varlena *toast_decompress_datum_slice(struct varlena *attr, int32 slicelength); -static int toast_open_indexes(Relation toastrel, - LOCKMODE lock, - Relation **toastidxs, - int *num_indexes); -static void toast_close_indexes(Relation *toastidxs, int num_indexes, - LOCKMODE lock); -static void init_toast_snapshot(Snapshot toast_snapshot); - - -/* ---------- - * heap_tuple_fetch_attr - - * - * Public entry point to get back a toasted value from - * external source (possibly still in compressed format). - * - * This will return a datum that contains all the data internally, ie, not - * relying on external storage or memory, but it can still be compressed or - * have a short header. Note some callers assume that if the input is an - * EXTERNAL datum, the result will be a pfree'able chunk. - * ---------- - */ -struct varlena * -heap_tuple_fetch_attr(struct varlena *attr) -{ - struct varlena *result; - - if (VARATT_IS_EXTERNAL_ONDISK(attr)) - { - /* - * This is an external stored plain value - */ - result = toast_fetch_datum(attr); - } - else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) - { - /* - * This is an indirect pointer --- dereference it - */ - struct varatt_indirect redirect; - - VARATT_EXTERNAL_GET_POINTER(redirect, attr); - attr = (struct varlena *) redirect.pointer; - - /* nested indirect Datums aren't allowed */ - Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); - - /* recurse if value is still external in some other way */ - if (VARATT_IS_EXTERNAL(attr)) - return heap_tuple_fetch_attr(attr); - - /* - * Copy into the caller's memory context, in case caller tries to - * pfree the result. - */ - result = (struct varlena *) palloc(VARSIZE_ANY(attr)); - memcpy(result, attr, VARSIZE_ANY(attr)); - } - else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) - { - /* - * This is an expanded-object pointer --- get flat format - */ - ExpandedObjectHeader *eoh; - Size resultsize; - - eoh = DatumGetEOHP(PointerGetDatum(attr)); - resultsize = EOH_get_flat_size(eoh); - result = (struct varlena *) palloc(resultsize); - EOH_flatten_into(eoh, (void *) result, resultsize); - } - else - { - /* - * This is a plain value inside of the main tuple - why am I called? - */ - result = attr; - } - - return result; -} - - -/* ---------- - * heap_tuple_untoast_attr - - * - * Public entry point to get back a toasted value from compression - * or external storage. The result is always non-extended varlena form. - * - * Note some callers assume that if the input is an EXTERNAL or COMPRESSED - * datum, the result will be a pfree'able chunk. - * ---------- - */ -struct varlena * -heap_tuple_untoast_attr(struct varlena *attr) -{ - if (VARATT_IS_EXTERNAL_ONDISK(attr)) - { - /* - * This is an externally stored datum --- fetch it back from there - */ - attr = toast_fetch_datum(attr); - /* If it's compressed, decompress it */ - if (VARATT_IS_COMPRESSED(attr)) - { - struct varlena *tmp = attr; - - attr = toast_decompress_datum(tmp); - pfree(tmp); - } - } - else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) - { - /* - * This is an indirect pointer --- dereference it - */ - struct varatt_indirect redirect; - - VARATT_EXTERNAL_GET_POINTER(redirect, attr); - attr = (struct varlena *) redirect.pointer; - - /* nested indirect Datums aren't allowed */ - Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); - - /* recurse in case value is still extended in some other way */ - attr = heap_tuple_untoast_attr(attr); - - /* if it isn't, we'd better copy it */ - if (attr == (struct varlena *) redirect.pointer) - { - struct varlena *result; - - result = (struct varlena *) palloc(VARSIZE_ANY(attr)); - memcpy(result, attr, VARSIZE_ANY(attr)); - attr = result; - } - } - else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) - { - /* - * This is an expanded-object pointer --- get flat format - */ - attr = heap_tuple_fetch_attr(attr); - /* flatteners are not allowed to produce compressed/short output */ - Assert(!VARATT_IS_EXTENDED(attr)); - } - else if (VARATT_IS_COMPRESSED(attr)) - { - /* - * This is a compressed value inside of the main tuple - */ - attr = toast_decompress_datum(attr); - } - else if (VARATT_IS_SHORT(attr)) - { - /* - * This is a short-header varlena --- convert to 4-byte header format - */ - Size data_size = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT; - Size new_size = data_size + VARHDRSZ; - struct varlena *new_attr; - - new_attr = (struct varlena *) palloc(new_size); - SET_VARSIZE(new_attr, new_size); - memcpy(VARDATA(new_attr), VARDATA_SHORT(attr), data_size); - attr = new_attr; - } - - return attr; -} - - -/* ---------- - * heap_tuple_untoast_attr_slice - - * - * Public entry point to get back part of a toasted value - * from compression or external storage. - * ---------- - */ -struct varlena * -heap_tuple_untoast_attr_slice(struct varlena *attr, - int32 sliceoffset, int32 slicelength) -{ - struct varlena *preslice; - struct varlena *result; - char *attrdata; - int32 attrsize; - - if (VARATT_IS_EXTERNAL_ONDISK(attr)) - { - struct varatt_external toast_pointer; - - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - /* fast path for non-compressed external datums */ - if (!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)) - return toast_fetch_datum_slice(attr, sliceoffset, slicelength); - - /* fetch it back (compressed marker will get set automatically) */ - preslice = toast_fetch_datum(attr); - } - else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) - { - struct varatt_indirect redirect; - - VARATT_EXTERNAL_GET_POINTER(redirect, attr); - - /* nested indirect Datums aren't allowed */ - Assert(!VARATT_IS_EXTERNAL_INDIRECT(redirect.pointer)); - - return heap_tuple_untoast_attr_slice(redirect.pointer, - sliceoffset, slicelength); - } - else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) - { - /* pass it off to heap_tuple_fetch_attr to flatten */ - preslice = heap_tuple_fetch_attr(attr); - } - else - preslice = attr; - - Assert(!VARATT_IS_EXTERNAL(preslice)); - - if (VARATT_IS_COMPRESSED(preslice)) - { - struct varlena *tmp = preslice; - - /* Decompress enough to encompass the slice and the offset */ - if (slicelength > 0 && sliceoffset >= 0) - preslice = toast_decompress_datum_slice(tmp, slicelength + sliceoffset); - else - preslice = toast_decompress_datum(tmp); - - if (tmp != attr) - pfree(tmp); - } - - if (VARATT_IS_SHORT(preslice)) - { - attrdata = VARDATA_SHORT(preslice); - attrsize = VARSIZE_SHORT(preslice) - VARHDRSZ_SHORT; - } - else - { - attrdata = VARDATA(preslice); - attrsize = VARSIZE(preslice) - VARHDRSZ; - } - - /* slicing of datum for compressed cases and plain value */ - - if (sliceoffset >= attrsize) - { - sliceoffset = 0; - slicelength = 0; - } - - if (((sliceoffset + slicelength) > attrsize) || slicelength < 0) - slicelength = attrsize - sliceoffset; - - result = (struct varlena *) palloc(slicelength + VARHDRSZ); - SET_VARSIZE(result, slicelength + VARHDRSZ); - - memcpy(VARDATA(result), attrdata + sliceoffset, slicelength); - - if (preslice != attr) - pfree(preslice); - - return result; -} - - -/* ---------- - * toast_raw_datum_size - - * - * Return the raw (detoasted) size of a varlena datum - * (including the VARHDRSZ header) - * ---------- - */ -Size -toast_raw_datum_size(Datum value) -{ - struct varlena *attr = (struct varlena *) DatumGetPointer(value); - Size result; - - if (VARATT_IS_EXTERNAL_ONDISK(attr)) - { - /* va_rawsize is the size of the original datum -- including header */ - struct varatt_external toast_pointer; - - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - result = toast_pointer.va_rawsize; - } - else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) - { - struct varatt_indirect toast_pointer; - - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - /* nested indirect Datums aren't allowed */ - Assert(!VARATT_IS_EXTERNAL_INDIRECT(toast_pointer.pointer)); - - return toast_raw_datum_size(PointerGetDatum(toast_pointer.pointer)); - } - else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) - { - result = EOH_get_flat_size(DatumGetEOHP(value)); - } - else if (VARATT_IS_COMPRESSED(attr)) - { - /* here, va_rawsize is just the payload size */ - result = VARRAWSIZE_4B_C(attr) + VARHDRSZ; - } - else if (VARATT_IS_SHORT(attr)) - { - /* - * we have to normalize the header length to VARHDRSZ or else the - * callers of this function will be confused. - */ - result = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT + VARHDRSZ; - } - else - { - /* plain untoasted datum */ - result = VARSIZE(attr); - } - return result; -} - -/* ---------- - * toast_datum_size - * - * Return the physical storage size (possibly compressed) of a varlena datum - * ---------- - */ -Size -toast_datum_size(Datum value) -{ - struct varlena *attr = (struct varlena *) DatumGetPointer(value); - Size result; - - if (VARATT_IS_EXTERNAL_ONDISK(attr)) - { - /* - * Attribute is stored externally - return the extsize whether - * compressed or not. We do not count the size of the toast pointer - * ... should we? - */ - struct varatt_external toast_pointer; - - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - result = toast_pointer.va_extsize; - } - else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) - { - struct varatt_indirect toast_pointer; - - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - /* nested indirect Datums aren't allowed */ - Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); - - return toast_datum_size(PointerGetDatum(toast_pointer.pointer)); - } - else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) - { - result = EOH_get_flat_size(DatumGetEOHP(value)); - } - else if (VARATT_IS_SHORT(attr)) - { - result = VARSIZE_SHORT(attr); - } - else - { - /* - * Attribute is stored inline either compressed or not, just calculate - * the size of the datum in either case. - */ - result = VARSIZE(attr); - } - return result; -} - - -/* ---------- - * toast_delete - - * - * Cascaded delete toast-entries on DELETE - * ---------- - */ -void -toast_delete(Relation rel, HeapTuple oldtup, bool is_speculative) -{ - TupleDesc tupleDesc; - int numAttrs; - int i; - Datum toast_values[MaxHeapAttributeNumber]; - bool toast_isnull[MaxHeapAttributeNumber]; - - /* - * We should only ever be called for tuples of plain relations or - * materialized views --- recursing on a toast rel is bad news. - */ - Assert(rel->rd_rel->relkind == RELKIND_RELATION || - rel->rd_rel->relkind == RELKIND_MATVIEW); - - /* - * Get the tuple descriptor and break down the tuple into fields. - * - * NOTE: it's debatable whether to use heap_deform_tuple() here or just - * heap_getattr() only the varlena columns. The latter could win if there - * are few varlena columns and many non-varlena ones. However, - * heap_deform_tuple costs only O(N) while the heap_getattr way would cost - * O(N^2) if there are many varlena columns, so it seems better to err on - * the side of linear cost. (We won't even be here unless there's at - * least one varlena column, by the way.) - */ - tupleDesc = rel->rd_att; - numAttrs = tupleDesc->natts; - - Assert(numAttrs <= MaxHeapAttributeNumber); - heap_deform_tuple(oldtup, tupleDesc, toast_values, toast_isnull); - - /* - * Check for external stored attributes and delete them from the secondary - * relation. - */ - for (i = 0; i < numAttrs; i++) - { - if (TupleDescAttr(tupleDesc, i)->attlen == -1) - { - Datum value = toast_values[i]; - - if (toast_isnull[i]) - continue; - else if (VARATT_IS_EXTERNAL_ONDISK(PointerGetDatum(value))) - toast_delete_datum(rel, value, is_speculative); - } - } -} - - -/* ---------- - * toast_insert_or_update - - * - * Delete no-longer-used toast-entries and create new ones to - * make the new tuple fit on INSERT or UPDATE - * - * Inputs: - * newtup: the candidate new tuple to be inserted - * oldtup: the old row version for UPDATE, or NULL for INSERT - * options: options to be passed to heap_insert() for toast rows - * Result: - * either newtup if no toasting is needed, or a palloc'd modified tuple - * that is what should actually get stored - * - * NOTE: neither newtup nor oldtup will be modified. This is a change - * from the pre-8.1 API of this routine. - * ---------- - */ -HeapTuple -toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, - int options) -{ - HeapTuple result_tuple; - TupleDesc tupleDesc; - int numAttrs; - int i; - - bool need_change = false; - bool need_free = false; - bool need_delold = false; - bool has_nulls = false; - - Size maxDataLen; - Size hoff; - - char toast_action[MaxHeapAttributeNumber]; - bool toast_isnull[MaxHeapAttributeNumber]; - bool toast_oldisnull[MaxHeapAttributeNumber]; - Datum toast_values[MaxHeapAttributeNumber]; - Datum toast_oldvalues[MaxHeapAttributeNumber]; - struct varlena *toast_oldexternal[MaxHeapAttributeNumber]; - int32 toast_sizes[MaxHeapAttributeNumber]; - bool toast_free[MaxHeapAttributeNumber]; - bool toast_delold[MaxHeapAttributeNumber]; - - /* - * Ignore the INSERT_SPECULATIVE option. Speculative insertions/super - * deletions just normally insert/delete the toast values. It seems - * easiest to deal with that here, instead on, potentially, multiple - * callers. - */ - options &= ~HEAP_INSERT_SPECULATIVE; - - /* - * We should only ever be called for tuples of plain relations or - * materialized views --- recursing on a toast rel is bad news. - */ - Assert(rel->rd_rel->relkind == RELKIND_RELATION || - rel->rd_rel->relkind == RELKIND_MATVIEW); - - /* - * Get the tuple descriptor and break down the tuple(s) into fields. - */ - tupleDesc = rel->rd_att; - numAttrs = tupleDesc->natts; - - Assert(numAttrs <= MaxHeapAttributeNumber); - heap_deform_tuple(newtup, tupleDesc, toast_values, toast_isnull); - if (oldtup != NULL) - heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull); - - /* ---------- - * Then collect information about the values given - * - * NOTE: toast_action[i] can have these values: - * ' ' default handling - * 'p' already processed --- don't touch it - * 'x' incompressible, but OK to move off - * - * NOTE: toast_sizes[i] is only made valid for varlena attributes with - * toast_action[i] different from 'p'. - * ---------- - */ - memset(toast_action, ' ', numAttrs * sizeof(char)); - memset(toast_oldexternal, 0, numAttrs * sizeof(struct varlena *)); - memset(toast_free, 0, numAttrs * sizeof(bool)); - memset(toast_delold, 0, numAttrs * sizeof(bool)); - - for (i = 0; i < numAttrs; i++) - { - Form_pg_attribute att = TupleDescAttr(tupleDesc, i); - struct varlena *old_value; - struct varlena *new_value; - - if (oldtup != NULL) - { - /* - * For UPDATE get the old and new values of this attribute - */ - old_value = (struct varlena *) DatumGetPointer(toast_oldvalues[i]); - new_value = (struct varlena *) DatumGetPointer(toast_values[i]); - - /* - * If the old value is stored on disk, check if it has changed so - * we have to delete it later. - */ - if (att->attlen == -1 && !toast_oldisnull[i] && - VARATT_IS_EXTERNAL_ONDISK(old_value)) - { - if (toast_isnull[i] || !VARATT_IS_EXTERNAL_ONDISK(new_value) || - memcmp((char *) old_value, (char *) new_value, - VARSIZE_EXTERNAL(old_value)) != 0) - { - /* - * The old external stored value isn't needed any more - * after the update - */ - toast_delold[i] = true; - need_delold = true; - } - else - { - /* - * This attribute isn't changed by this update so we reuse - * the original reference to the old value in the new - * tuple. - */ - toast_action[i] = 'p'; - continue; - } - } - } - else - { - /* - * For INSERT simply get the new value - */ - new_value = (struct varlena *) DatumGetPointer(toast_values[i]); - } - - /* - * Handle NULL attributes - */ - if (toast_isnull[i]) - { - toast_action[i] = 'p'; - has_nulls = true; - continue; - } - - /* - * Now look at varlena attributes - */ - if (att->attlen == -1) - { - /* - * If the table's attribute says PLAIN always, force it so. - */ - if (att->attstorage == 'p') - toast_action[i] = 'p'; - - /* - * We took care of UPDATE above, so any external value we find - * still in the tuple must be someone else's that we cannot reuse - * (this includes the case of an out-of-line in-memory datum). - * Fetch it back (without decompression, unless we are forcing - * PLAIN storage). If necessary, we'll push it out as a new - * external value below. - */ - if (VARATT_IS_EXTERNAL(new_value)) - { - toast_oldexternal[i] = new_value; - if (att->attstorage == 'p') - new_value = heap_tuple_untoast_attr(new_value); - else - new_value = heap_tuple_fetch_attr(new_value); - toast_values[i] = PointerGetDatum(new_value); - toast_free[i] = true; - need_change = true; - need_free = true; - } - - /* - * Remember the size of this attribute - */ - toast_sizes[i] = VARSIZE_ANY(new_value); - } - else - { - /* - * Not a varlena attribute, plain storage always - */ - toast_action[i] = 'p'; - } - } - - /* ---------- - * Compress and/or save external until data fits into target length - * - * 1: Inline compress attributes with attstorage 'x', and store very - * large attributes with attstorage 'x' or 'e' external immediately - * 2: Store attributes with attstorage 'x' or 'e' external - * 3: Inline compress attributes with attstorage 'm' - * 4: Store attributes with attstorage 'm' external - * ---------- - */ - - /* compute header overhead --- this should match heap_form_tuple() */ - hoff = SizeofHeapTupleHeader; - if (has_nulls) - hoff += BITMAPLEN(numAttrs); - hoff = MAXALIGN(hoff); - /* now convert to a limit on the tuple data size */ - maxDataLen = RelationGetToastTupleTarget(rel, TOAST_TUPLE_TARGET) - hoff; - - /* - * Look for attributes with attstorage 'x' to compress. Also find large - * attributes with attstorage 'x' or 'e', and store them external. - */ - while (heap_compute_data_size(tupleDesc, - toast_values, toast_isnull) > maxDataLen) - { - int biggest_attno = -1; - int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); - Datum old_value; - Datum new_value; - - /* - * Search for the biggest yet unprocessed internal attribute - */ - for (i = 0; i < numAttrs; i++) - { - Form_pg_attribute att = TupleDescAttr(tupleDesc, i); - - if (toast_action[i] != ' ') - continue; - if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) - continue; /* can't happen, toast_action would be 'p' */ - if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i]))) - continue; - if (att->attstorage != 'x' && att->attstorage != 'e') - continue; - if (toast_sizes[i] > biggest_size) - { - biggest_attno = i; - biggest_size = toast_sizes[i]; - } - } - - if (biggest_attno < 0) - break; - - /* - * Attempt to compress it inline, if it has attstorage 'x' - */ - i = biggest_attno; - if (TupleDescAttr(tupleDesc, i)->attstorage == 'x') - { - old_value = toast_values[i]; - new_value = toast_compress_datum(old_value); - - if (DatumGetPointer(new_value) != NULL) - { - /* successful compression */ - if (toast_free[i]) - pfree(DatumGetPointer(old_value)); - toast_values[i] = new_value; - toast_free[i] = true; - toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i])); - need_change = true; - need_free = true; - } - else - { - /* incompressible, ignore on subsequent compression passes */ - toast_action[i] = 'x'; - } - } - else - { - /* has attstorage 'e', ignore on subsequent compression passes */ - toast_action[i] = 'x'; - } - - /* - * If this value is by itself more than maxDataLen (after compression - * if any), push it out to the toast table immediately, if possible. - * This avoids uselessly compressing other fields in the common case - * where we have one long field and several short ones. - * - * XXX maybe the threshold should be less than maxDataLen? - */ - if (toast_sizes[i] > maxDataLen && - rel->rd_rel->reltoastrelid != InvalidOid) - { - old_value = toast_values[i]; - toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], - toast_oldexternal[i], options); - if (toast_free[i]) - pfree(DatumGetPointer(old_value)); - toast_free[i] = true; - need_change = true; - need_free = true; - } - } - - /* - * Second we look for attributes of attstorage 'x' or 'e' that are still - * inline. But skip this if there's no toast table to push them to. - */ - while (heap_compute_data_size(tupleDesc, - toast_values, toast_isnull) > maxDataLen && - rel->rd_rel->reltoastrelid != InvalidOid) - { - int biggest_attno = -1; - int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); - Datum old_value; - - /*------ - * Search for the biggest yet inlined attribute with - * attstorage equals 'x' or 'e' - *------ - */ - for (i = 0; i < numAttrs; i++) - { - Form_pg_attribute att = TupleDescAttr(tupleDesc, i); - - if (toast_action[i] == 'p') - continue; - if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) - continue; /* can't happen, toast_action would be 'p' */ - if (att->attstorage != 'x' && att->attstorage != 'e') - continue; - if (toast_sizes[i] > biggest_size) - { - biggest_attno = i; - biggest_size = toast_sizes[i]; - } - } - - if (biggest_attno < 0) - break; - - /* - * Store this external - */ - i = biggest_attno; - old_value = toast_values[i]; - toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], - toast_oldexternal[i], options); - if (toast_free[i]) - pfree(DatumGetPointer(old_value)); - toast_free[i] = true; - - need_change = true; - need_free = true; - } - - /* - * Round 3 - this time we take attributes with storage 'm' into - * compression - */ - while (heap_compute_data_size(tupleDesc, - toast_values, toast_isnull) > maxDataLen) - { - int biggest_attno = -1; - int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); - Datum old_value; - Datum new_value; - - /* - * Search for the biggest yet uncompressed internal attribute - */ - for (i = 0; i < numAttrs; i++) - { - if (toast_action[i] != ' ') - continue; - if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) - continue; /* can't happen, toast_action would be 'p' */ - if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i]))) - continue; - if (TupleDescAttr(tupleDesc, i)->attstorage != 'm') - continue; - if (toast_sizes[i] > biggest_size) - { - biggest_attno = i; - biggest_size = toast_sizes[i]; - } - } - - if (biggest_attno < 0) - break; - - /* - * Attempt to compress it inline - */ - i = biggest_attno; - old_value = toast_values[i]; - new_value = toast_compress_datum(old_value); - - if (DatumGetPointer(new_value) != NULL) - { - /* successful compression */ - if (toast_free[i]) - pfree(DatumGetPointer(old_value)); - toast_values[i] = new_value; - toast_free[i] = true; - toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i])); - need_change = true; - need_free = true; - } - else - { - /* incompressible, ignore on subsequent compression passes */ - toast_action[i] = 'x'; - } - } - - /* - * Finally we store attributes of type 'm' externally. At this point we - * increase the target tuple size, so that 'm' attributes aren't stored - * externally unless really necessary. - */ - maxDataLen = TOAST_TUPLE_TARGET_MAIN - hoff; - - while (heap_compute_data_size(tupleDesc, - toast_values, toast_isnull) > maxDataLen && - rel->rd_rel->reltoastrelid != InvalidOid) - { - int biggest_attno = -1; - int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); - Datum old_value; - - /*-------- - * Search for the biggest yet inlined attribute with - * attstorage = 'm' - *-------- - */ - for (i = 0; i < numAttrs; i++) - { - if (toast_action[i] == 'p') - continue; - if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) - continue; /* can't happen, toast_action would be 'p' */ - if (TupleDescAttr(tupleDesc, i)->attstorage != 'm') - continue; - if (toast_sizes[i] > biggest_size) - { - biggest_attno = i; - biggest_size = toast_sizes[i]; - } - } - - if (biggest_attno < 0) - break; - - /* - * Store this external - */ - i = biggest_attno; - old_value = toast_values[i]; - toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], - toast_oldexternal[i], options); - if (toast_free[i]) - pfree(DatumGetPointer(old_value)); - toast_free[i] = true; - - need_change = true; - need_free = true; - } - - /* - * In the case we toasted any values, we need to build a new heap tuple - * with the changed values. - */ - if (need_change) - { - HeapTupleHeader olddata = newtup->t_data; - HeapTupleHeader new_data; - int32 new_header_len; - int32 new_data_len; - int32 new_tuple_len; - - /* - * Calculate the new size of the tuple. - * - * Note: we used to assume here that the old tuple's t_hoff must equal - * the new_header_len value, but that was incorrect. The old tuple - * might have a smaller-than-current natts, if there's been an ALTER - * TABLE ADD COLUMN since it was stored; and that would lead to a - * different conclusion about the size of the null bitmap, or even - * whether there needs to be one at all. - */ - new_header_len = SizeofHeapTupleHeader; - if (has_nulls) - new_header_len += BITMAPLEN(numAttrs); - new_header_len = MAXALIGN(new_header_len); - new_data_len = heap_compute_data_size(tupleDesc, - toast_values, toast_isnull); - new_tuple_len = new_header_len + new_data_len; - - /* - * Allocate and zero the space needed, and fill HeapTupleData fields. - */ - result_tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + new_tuple_len); - result_tuple->t_len = new_tuple_len; - result_tuple->t_self = newtup->t_self; - result_tuple->t_tableOid = newtup->t_tableOid; - new_data = (HeapTupleHeader) ((char *) result_tuple + HEAPTUPLESIZE); - result_tuple->t_data = new_data; - - /* - * Copy the existing tuple header, but adjust natts and t_hoff. - */ - memcpy(new_data, olddata, SizeofHeapTupleHeader); - HeapTupleHeaderSetNatts(new_data, numAttrs); - new_data->t_hoff = new_header_len; - - /* Copy over the data, and fill the null bitmap if needed */ - heap_fill_tuple(tupleDesc, - toast_values, - toast_isnull, - (char *) new_data + new_header_len, - new_data_len, - &(new_data->t_infomask), - has_nulls ? new_data->t_bits : NULL); - } - else - result_tuple = newtup; - - /* - * Free allocated temp values - */ - if (need_free) - for (i = 0; i < numAttrs; i++) - if (toast_free[i]) - pfree(DatumGetPointer(toast_values[i])); - - /* - * Delete external values from the old tuple - */ - if (need_delold) - for (i = 0; i < numAttrs; i++) - if (toast_delold[i]) - toast_delete_datum(rel, toast_oldvalues[i], false); - - return result_tuple; -} - - -/* ---------- - * toast_flatten_tuple - - * - * "Flatten" a tuple to contain no out-of-line toasted fields. - * (This does not eliminate compressed or short-header datums.) - * - * Note: we expect the caller already checked HeapTupleHasExternal(tup), - * so there is no need for a short-circuit path. - * ---------- - */ -HeapTuple -toast_flatten_tuple(HeapTuple tup, TupleDesc tupleDesc) -{ - HeapTuple new_tuple; - int numAttrs = tupleDesc->natts; - int i; - Datum toast_values[MaxTupleAttributeNumber]; - bool toast_isnull[MaxTupleAttributeNumber]; - bool toast_free[MaxTupleAttributeNumber]; - - /* - * Break down the tuple into fields. - */ - Assert(numAttrs <= MaxTupleAttributeNumber); - heap_deform_tuple(tup, tupleDesc, toast_values, toast_isnull); - - memset(toast_free, 0, numAttrs * sizeof(bool)); - - for (i = 0; i < numAttrs; i++) - { - /* - * Look at non-null varlena attributes - */ - if (!toast_isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1) - { - struct varlena *new_value; - - new_value = (struct varlena *) DatumGetPointer(toast_values[i]); - if (VARATT_IS_EXTERNAL(new_value)) - { - new_value = heap_tuple_fetch_attr(new_value); - toast_values[i] = PointerGetDatum(new_value); - toast_free[i] = true; - } - } - } - - /* - * Form the reconfigured tuple. - */ - new_tuple = heap_form_tuple(tupleDesc, toast_values, toast_isnull); - - /* - * Be sure to copy the tuple's identity fields. We also make a point of - * copying visibility info, just in case anybody looks at those fields in - * a syscache entry. - */ - new_tuple->t_self = tup->t_self; - new_tuple->t_tableOid = tup->t_tableOid; - - new_tuple->t_data->t_choice = tup->t_data->t_choice; - new_tuple->t_data->t_ctid = tup->t_data->t_ctid; - new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK; - new_tuple->t_data->t_infomask |= - tup->t_data->t_infomask & HEAP_XACT_MASK; - new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK; - new_tuple->t_data->t_infomask2 |= - tup->t_data->t_infomask2 & HEAP2_XACT_MASK; - - /* - * Free allocated temp values - */ - for (i = 0; i < numAttrs; i++) - if (toast_free[i]) - pfree(DatumGetPointer(toast_values[i])); - - return new_tuple; -} - - -/* ---------- - * toast_flatten_tuple_to_datum - - * - * "Flatten" a tuple containing out-of-line toasted fields into a Datum. - * The result is always palloc'd in the current memory context. - * - * We have a general rule that Datums of container types (rows, arrays, - * ranges, etc) must not contain any external TOAST pointers. Without - * this rule, we'd have to look inside each Datum when preparing a tuple - * for storage, which would be expensive and would fail to extend cleanly - * to new sorts of container types. - * - * However, we don't want to say that tuples represented as HeapTuples - * can't contain toasted fields, so instead this routine should be called - * when such a HeapTuple is being converted into a Datum. - * - * While we're at it, we decompress any compressed fields too. This is not - * necessary for correctness, but reflects an expectation that compression - * will be more effective if applied to the whole tuple not individual - * fields. We are not so concerned about that that we want to deconstruct - * and reconstruct tuples just to get rid of compressed fields, however. - * So callers typically won't call this unless they see that the tuple has - * at least one external field. - * - * On the other hand, in-line short-header varlena fields are left alone. - * If we "untoasted" them here, they'd just get changed back to short-header - * format anyway within heap_fill_tuple. - * ---------- - */ -Datum -toast_flatten_tuple_to_datum(HeapTupleHeader tup, - uint32 tup_len, - TupleDesc tupleDesc) -{ - HeapTupleHeader new_data; - int32 new_header_len; - int32 new_data_len; - int32 new_tuple_len; - HeapTupleData tmptup; - int numAttrs = tupleDesc->natts; - int i; - bool has_nulls = false; - Datum toast_values[MaxTupleAttributeNumber]; - bool toast_isnull[MaxTupleAttributeNumber]; - bool toast_free[MaxTupleAttributeNumber]; - - /* Build a temporary HeapTuple control structure */ - tmptup.t_len = tup_len; - ItemPointerSetInvalid(&(tmptup.t_self)); - tmptup.t_tableOid = InvalidOid; - tmptup.t_data = tup; - - /* - * Break down the tuple into fields. - */ - Assert(numAttrs <= MaxTupleAttributeNumber); - heap_deform_tuple(&tmptup, tupleDesc, toast_values, toast_isnull); - - memset(toast_free, 0, numAttrs * sizeof(bool)); - - for (i = 0; i < numAttrs; i++) - { - /* - * Look at non-null varlena attributes - */ - if (toast_isnull[i]) - has_nulls = true; - else if (TupleDescAttr(tupleDesc, i)->attlen == -1) - { - struct varlena *new_value; - - new_value = (struct varlena *) DatumGetPointer(toast_values[i]); - if (VARATT_IS_EXTERNAL(new_value) || - VARATT_IS_COMPRESSED(new_value)) - { - new_value = heap_tuple_untoast_attr(new_value); - toast_values[i] = PointerGetDatum(new_value); - toast_free[i] = true; - } - } - } - - /* - * Calculate the new size of the tuple. - * - * This should match the reconstruction code in toast_insert_or_update. - */ - new_header_len = SizeofHeapTupleHeader; - if (has_nulls) - new_header_len += BITMAPLEN(numAttrs); - new_header_len = MAXALIGN(new_header_len); - new_data_len = heap_compute_data_size(tupleDesc, - toast_values, toast_isnull); - new_tuple_len = new_header_len + new_data_len; - - new_data = (HeapTupleHeader) palloc0(new_tuple_len); - - /* - * Copy the existing tuple header, but adjust natts and t_hoff. - */ - memcpy(new_data, tup, SizeofHeapTupleHeader); - HeapTupleHeaderSetNatts(new_data, numAttrs); - new_data->t_hoff = new_header_len; - - /* Set the composite-Datum header fields correctly */ - HeapTupleHeaderSetDatumLength(new_data, new_tuple_len); - HeapTupleHeaderSetTypeId(new_data, tupleDesc->tdtypeid); - HeapTupleHeaderSetTypMod(new_data, tupleDesc->tdtypmod); - - /* Copy over the data, and fill the null bitmap if needed */ - heap_fill_tuple(tupleDesc, - toast_values, - toast_isnull, - (char *) new_data + new_header_len, - new_data_len, - &(new_data->t_infomask), - has_nulls ? new_data->t_bits : NULL); - - /* - * Free allocated temp values - */ - for (i = 0; i < numAttrs; i++) - if (toast_free[i]) - pfree(DatumGetPointer(toast_values[i])); - - return PointerGetDatum(new_data); -} - - -/* ---------- - * toast_build_flattened_tuple - - * - * Build a tuple containing no out-of-line toasted fields. - * (This does not eliminate compressed or short-header datums.) - * - * This is essentially just like heap_form_tuple, except that it will - * expand any external-data pointers beforehand. - * - * It's not very clear whether it would be preferable to decompress - * in-line compressed datums while at it. For now, we don't. - * ---------- - */ -HeapTuple -toast_build_flattened_tuple(TupleDesc tupleDesc, - Datum *values, - bool *isnull) -{ - HeapTuple new_tuple; - int numAttrs = tupleDesc->natts; - int num_to_free; - int i; - Datum new_values[MaxTupleAttributeNumber]; - Pointer freeable_values[MaxTupleAttributeNumber]; - - /* - * We can pass the caller's isnull array directly to heap_form_tuple, but - * we potentially need to modify the values array. - */ - Assert(numAttrs <= MaxTupleAttributeNumber); - memcpy(new_values, values, numAttrs * sizeof(Datum)); - - num_to_free = 0; - for (i = 0; i < numAttrs; i++) - { - /* - * Look at non-null varlena attributes - */ - if (!isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1) - { - struct varlena *new_value; - - new_value = (struct varlena *) DatumGetPointer(new_values[i]); - if (VARATT_IS_EXTERNAL(new_value)) - { - new_value = heap_tuple_fetch_attr(new_value); - new_values[i] = PointerGetDatum(new_value); - freeable_values[num_to_free++] = (Pointer) new_value; - } - } - } - - /* - * Form the reconfigured tuple. - */ - new_tuple = heap_form_tuple(tupleDesc, new_values, isnull); - - /* - * Free allocated temp values - */ - for (i = 0; i < num_to_free; i++) - pfree(freeable_values[i]); - - return new_tuple; -} - - -/* ---------- - * toast_compress_datum - - * - * Create a compressed version of a varlena datum - * - * If we fail (ie, compressed result is actually bigger than original) - * then return NULL. We must not use compressed data if it'd expand - * the tuple! - * - * We use VAR{SIZE,DATA}_ANY so we can handle short varlenas here without - * copying them. But we can't handle external or compressed datums. - * ---------- - */ -Datum -toast_compress_datum(Datum value) -{ - struct varlena *tmp; - int32 valsize = VARSIZE_ANY_EXHDR(DatumGetPointer(value)); - int32 len; - - Assert(!VARATT_IS_EXTERNAL(DatumGetPointer(value))); - Assert(!VARATT_IS_COMPRESSED(DatumGetPointer(value))); - - /* - * No point in wasting a palloc cycle if value size is out of the allowed - * range for compression - */ - if (valsize < PGLZ_strategy_default->min_input_size || - valsize > PGLZ_strategy_default->max_input_size) - return PointerGetDatum(NULL); - - tmp = (struct varlena *) palloc(PGLZ_MAX_OUTPUT(valsize) + - TOAST_COMPRESS_HDRSZ); - - /* - * We recheck the actual size even if pglz_compress() reports success, - * because it might be satisfied with having saved as little as one byte - * in the compressed data --- which could turn into a net loss once you - * consider header and alignment padding. Worst case, the compressed - * format might require three padding bytes (plus header, which is - * included in VARSIZE(tmp)), whereas the uncompressed format would take - * only one header byte and no padding if the value is short enough. So - * we insist on a savings of more than 2 bytes to ensure we have a gain. - */ - len = pglz_compress(VARDATA_ANY(DatumGetPointer(value)), - valsize, - TOAST_COMPRESS_RAWDATA(tmp), - PGLZ_strategy_default); - if (len >= 0 && - len + TOAST_COMPRESS_HDRSZ < valsize - 2) - { - TOAST_COMPRESS_SET_RAWSIZE(tmp, valsize); - SET_VARSIZE_COMPRESSED(tmp, len + TOAST_COMPRESS_HDRSZ); - /* successful compression */ - return PointerGetDatum(tmp); - } - else - { - /* incompressible data */ - pfree(tmp); - return PointerGetDatum(NULL); - } -} - - -/* ---------- - * toast_get_valid_index - * - * Get OID of valid index associated to given toast relation. A toast - * relation can have only one valid index at the same time. - */ -Oid -toast_get_valid_index(Oid toastoid, LOCKMODE lock) -{ - int num_indexes; - int validIndex; - Oid validIndexOid; - Relation *toastidxs; - Relation toastrel; - - /* Open the toast relation */ - toastrel = table_open(toastoid, lock); - - /* Look for the valid index of the toast relation */ - validIndex = toast_open_indexes(toastrel, - lock, - &toastidxs, - &num_indexes); - validIndexOid = RelationGetRelid(toastidxs[validIndex]); - - /* Close the toast relation and all its indexes */ - toast_close_indexes(toastidxs, num_indexes, lock); - table_close(toastrel, lock); - - return validIndexOid; -} - - -/* ---------- - * toast_save_datum - - * - * Save one single datum into the secondary relation and return - * a Datum reference for it. - * - * rel: the main relation we're working with (not the toast rel!) - * value: datum to be pushed to toast storage - * oldexternal: if not NULL, toast pointer previously representing the datum - * options: options to be passed to heap_insert() for toast rows - * ---------- - */ -static Datum -toast_save_datum(Relation rel, Datum value, - struct varlena *oldexternal, int options) -{ - Relation toastrel; - Relation *toastidxs; - HeapTuple toasttup; - TupleDesc toasttupDesc; - Datum t_values[3]; - bool t_isnull[3]; - CommandId mycid = GetCurrentCommandId(true); - struct varlena *result; - struct varatt_external toast_pointer; - union - { - struct varlena hdr; - /* this is to make the union big enough for a chunk: */ - char data[TOAST_MAX_CHUNK_SIZE + VARHDRSZ]; - /* ensure union is aligned well enough: */ - int32 align_it; - } chunk_data; - int32 chunk_size; - int32 chunk_seq = 0; - char *data_p; - int32 data_todo; - Pointer dval = DatumGetPointer(value); - int num_indexes; - int validIndex; - - Assert(!VARATT_IS_EXTERNAL(value)); - - /* - * Open the toast relation and its indexes. We can use the index to check - * uniqueness of the OID we assign to the toasted item, even though it has - * additional columns besides OID. - */ - toastrel = table_open(rel->rd_rel->reltoastrelid, RowExclusiveLock); - toasttupDesc = toastrel->rd_att; - - /* Open all the toast indexes and look for the valid one */ - validIndex = toast_open_indexes(toastrel, - RowExclusiveLock, - &toastidxs, - &num_indexes); - - /* - * Get the data pointer and length, and compute va_rawsize and va_extsize. - * - * va_rawsize is the size of the equivalent fully uncompressed datum, so - * we have to adjust for short headers. - * - * va_extsize is the actual size of the data payload in the toast records. - */ - if (VARATT_IS_SHORT(dval)) - { - data_p = VARDATA_SHORT(dval); - data_todo = VARSIZE_SHORT(dval) - VARHDRSZ_SHORT; - toast_pointer.va_rawsize = data_todo + VARHDRSZ; /* as if not short */ - toast_pointer.va_extsize = data_todo; - } - else if (VARATT_IS_COMPRESSED(dval)) - { - data_p = VARDATA(dval); - data_todo = VARSIZE(dval) - VARHDRSZ; - /* rawsize in a compressed datum is just the size of the payload */ - toast_pointer.va_rawsize = VARRAWSIZE_4B_C(dval) + VARHDRSZ; - toast_pointer.va_extsize = data_todo; - /* Assert that the numbers look like it's compressed */ - Assert(VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)); - } - else - { - data_p = VARDATA(dval); - data_todo = VARSIZE(dval) - VARHDRSZ; - toast_pointer.va_rawsize = VARSIZE(dval); - toast_pointer.va_extsize = data_todo; - } - - /* - * Insert the correct table OID into the result TOAST pointer. - * - * Normally this is the actual OID of the target toast table, but during - * table-rewriting operations such as CLUSTER, we have to insert the OID - * of the table's real permanent toast table instead. rd_toastoid is set - * if we have to substitute such an OID. - */ - if (OidIsValid(rel->rd_toastoid)) - toast_pointer.va_toastrelid = rel->rd_toastoid; - else - toast_pointer.va_toastrelid = RelationGetRelid(toastrel); - - /* - * Choose an OID to use as the value ID for this toast value. - * - * Normally we just choose an unused OID within the toast table. But - * during table-rewriting operations where we are preserving an existing - * toast table OID, we want to preserve toast value OIDs too. So, if - * rd_toastoid is set and we had a prior external value from that same - * toast table, re-use its value ID. If we didn't have a prior external - * value (which is a corner case, but possible if the table's attstorage - * options have been changed), we have to pick a value ID that doesn't - * conflict with either new or existing toast value OIDs. - */ - if (!OidIsValid(rel->rd_toastoid)) - { - /* normal case: just choose an unused OID */ - toast_pointer.va_valueid = - GetNewOidWithIndex(toastrel, - RelationGetRelid(toastidxs[validIndex]), - (AttrNumber) 1); - } - else - { - /* rewrite case: check to see if value was in old toast table */ - toast_pointer.va_valueid = InvalidOid; - if (oldexternal != NULL) - { - struct varatt_external old_toast_pointer; - - Assert(VARATT_IS_EXTERNAL_ONDISK(oldexternal)); - /* Must copy to access aligned fields */ - VARATT_EXTERNAL_GET_POINTER(old_toast_pointer, oldexternal); - if (old_toast_pointer.va_toastrelid == rel->rd_toastoid) - { - /* This value came from the old toast table; reuse its OID */ - toast_pointer.va_valueid = old_toast_pointer.va_valueid; - - /* - * There is a corner case here: the table rewrite might have - * to copy both live and recently-dead versions of a row, and - * those versions could easily reference the same toast value. - * When we copy the second or later version of such a row, - * reusing the OID will mean we select an OID that's already - * in the new toast table. Check for that, and if so, just - * fall through without writing the data again. - * - * While annoying and ugly-looking, this is a good thing - * because it ensures that we wind up with only one copy of - * the toast value when there is only one copy in the old - * toast table. Before we detected this case, we'd have made - * multiple copies, wasting space; and what's worse, the - * copies belonging to already-deleted heap tuples would not - * be reclaimed by VACUUM. - */ - if (toastrel_valueid_exists(toastrel, - toast_pointer.va_valueid)) - { - /* Match, so short-circuit the data storage loop below */ - data_todo = 0; - } - } - } - if (toast_pointer.va_valueid == InvalidOid) - { - /* - * new value; must choose an OID that doesn't conflict in either - * old or new toast table - */ - do - { - toast_pointer.va_valueid = - GetNewOidWithIndex(toastrel, - RelationGetRelid(toastidxs[validIndex]), - (AttrNumber) 1); - } while (toastid_valueid_exists(rel->rd_toastoid, - toast_pointer.va_valueid)); - } - } - - /* - * Initialize constant parts of the tuple data - */ - t_values[0] = ObjectIdGetDatum(toast_pointer.va_valueid); - t_values[2] = PointerGetDatum(&chunk_data); - t_isnull[0] = false; - t_isnull[1] = false; - t_isnull[2] = false; - - /* - * Split up the item into chunks - */ - while (data_todo > 0) - { - int i; - - CHECK_FOR_INTERRUPTS(); - - /* - * Calculate the size of this chunk - */ - chunk_size = Min(TOAST_MAX_CHUNK_SIZE, data_todo); - - /* - * Build a tuple and store it - */ - t_values[1] = Int32GetDatum(chunk_seq++); - SET_VARSIZE(&chunk_data, chunk_size + VARHDRSZ); - memcpy(VARDATA(&chunk_data), data_p, chunk_size); - toasttup = heap_form_tuple(toasttupDesc, t_values, t_isnull); - - heap_insert(toastrel, toasttup, mycid, options, NULL); - - /* - * Create the index entry. We cheat a little here by not using - * FormIndexDatum: this relies on the knowledge that the index columns - * are the same as the initial columns of the table for all the - * indexes. We also cheat by not providing an IndexInfo: this is okay - * for now because btree doesn't need one, but we might have to be - * more honest someday. - * - * Note also that there had better not be any user-created index on - * the TOAST table, since we don't bother to update anything else. - */ - for (i = 0; i < num_indexes; i++) - { - /* Only index relations marked as ready can be updated */ - if (toastidxs[i]->rd_index->indisready) - index_insert(toastidxs[i], t_values, t_isnull, - &(toasttup->t_self), - toastrel, - toastidxs[i]->rd_index->indisunique ? - UNIQUE_CHECK_YES : UNIQUE_CHECK_NO, - NULL); - } - - /* - * Free memory - */ - heap_freetuple(toasttup); - - /* - * Move on to next chunk - */ - data_todo -= chunk_size; - data_p += chunk_size; - } - - /* - * Done - close toast relation and its indexes - */ - toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); - table_close(toastrel, RowExclusiveLock); - - /* - * Create the TOAST pointer value that we'll return - */ - result = (struct varlena *) palloc(TOAST_POINTER_SIZE); - SET_VARTAG_EXTERNAL(result, VARTAG_ONDISK); - memcpy(VARDATA_EXTERNAL(result), &toast_pointer, sizeof(toast_pointer)); - - return PointerGetDatum(result); -} - - -/* ---------- - * toast_delete_datum - - * - * Delete a single external stored value. - * ---------- - */ -static void -toast_delete_datum(Relation rel, Datum value, bool is_speculative) -{ - struct varlena *attr = (struct varlena *) DatumGetPointer(value); - struct varatt_external toast_pointer; - Relation toastrel; - Relation *toastidxs; - ScanKeyData toastkey; - SysScanDesc toastscan; - HeapTuple toasttup; - int num_indexes; - int validIndex; - SnapshotData SnapshotToast; - - if (!VARATT_IS_EXTERNAL_ONDISK(attr)) - return; - - /* Must copy to access aligned fields */ - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - /* - * Open the toast relation and its indexes - */ - toastrel = table_open(toast_pointer.va_toastrelid, RowExclusiveLock); - - /* Fetch valid relation used for process */ - validIndex = toast_open_indexes(toastrel, - RowExclusiveLock, - &toastidxs, - &num_indexes); - - /* - * Setup a scan key to find chunks with matching va_valueid - */ - ScanKeyInit(&toastkey, - (AttrNumber) 1, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(toast_pointer.va_valueid)); - - /* - * Find all the chunks. (We don't actually care whether we see them in - * sequence or not, but since we've already locked the index we might as - * well use systable_beginscan_ordered.) - */ - init_toast_snapshot(&SnapshotToast); - toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], - &SnapshotToast, 1, &toastkey); - while ((toasttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) - { - /* - * Have a chunk, delete it - */ - if (is_speculative) - heap_abort_speculative(toastrel, &toasttup->t_self); - else - simple_heap_delete(toastrel, &toasttup->t_self); - } - - /* - * End scan and close relations - */ - systable_endscan_ordered(toastscan); - toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); - table_close(toastrel, RowExclusiveLock); -} - - -/* ---------- - * toastrel_valueid_exists - - * - * Test whether a toast value with the given ID exists in the toast relation. - * For safety, we consider a value to exist if there are either live or dead - * toast rows with that ID; see notes for GetNewOidWithIndex(). - * ---------- - */ -static bool -toastrel_valueid_exists(Relation toastrel, Oid valueid) -{ - bool result = false; - ScanKeyData toastkey; - SysScanDesc toastscan; - int num_indexes; - int validIndex; - Relation *toastidxs; - - /* Fetch a valid index relation */ - validIndex = toast_open_indexes(toastrel, - RowExclusiveLock, - &toastidxs, - &num_indexes); - - /* - * Setup a scan key to find chunks with matching va_valueid - */ - ScanKeyInit(&toastkey, - (AttrNumber) 1, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(valueid)); - - /* - * Is there any such chunk? - */ - toastscan = systable_beginscan(toastrel, - RelationGetRelid(toastidxs[validIndex]), - true, SnapshotAny, 1, &toastkey); - - if (systable_getnext(toastscan) != NULL) - result = true; - - systable_endscan(toastscan); - - /* Clean up */ - toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); - - return result; -} - -/* ---------- - * toastid_valueid_exists - - * - * As above, but work from toast rel's OID not an open relation - * ---------- - */ -static bool -toastid_valueid_exists(Oid toastrelid, Oid valueid) -{ - bool result; - Relation toastrel; - - toastrel = table_open(toastrelid, AccessShareLock); - - result = toastrel_valueid_exists(toastrel, valueid); - - table_close(toastrel, AccessShareLock); - - return result; -} - - -/* ---------- - * toast_fetch_datum - - * - * Reconstruct an in memory Datum from the chunks saved - * in the toast relation - * ---------- - */ -static struct varlena * -toast_fetch_datum(struct varlena *attr) -{ - Relation toastrel; - Relation *toastidxs; - ScanKeyData toastkey; - SysScanDesc toastscan; - HeapTuple ttup; - TupleDesc toasttupDesc; - struct varlena *result; - struct varatt_external toast_pointer; - int32 ressize; - int32 residx, - nextidx; - int32 numchunks; - Pointer chunk; - bool isnull; - char *chunkdata; - int32 chunksize; - int num_indexes; - int validIndex; - SnapshotData SnapshotToast; - - if (!VARATT_IS_EXTERNAL_ONDISK(attr)) - elog(ERROR, "toast_fetch_datum shouldn't be called for non-ondisk datums"); - - /* Must copy to access aligned fields */ - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - ressize = toast_pointer.va_extsize; - numchunks = ((ressize - 1) / TOAST_MAX_CHUNK_SIZE) + 1; - - result = (struct varlena *) palloc(ressize + VARHDRSZ); - - if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)) - SET_VARSIZE_COMPRESSED(result, ressize + VARHDRSZ); - else - SET_VARSIZE(result, ressize + VARHDRSZ); - - /* - * Open the toast relation and its indexes - */ - toastrel = table_open(toast_pointer.va_toastrelid, AccessShareLock); - toasttupDesc = toastrel->rd_att; - - /* Look for the valid index of the toast relation */ - validIndex = toast_open_indexes(toastrel, - AccessShareLock, - &toastidxs, - &num_indexes); - - /* - * Setup a scan key to fetch from the index by va_valueid - */ - ScanKeyInit(&toastkey, - (AttrNumber) 1, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(toast_pointer.va_valueid)); - - /* - * Read the chunks by index - * - * Note that because the index is actually on (valueid, chunkidx) we will - * see the chunks in chunkidx order, even though we didn't explicitly ask - * for it. - */ - nextidx = 0; - - init_toast_snapshot(&SnapshotToast); - toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], - &SnapshotToast, 1, &toastkey); - while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) - { - /* - * Have a chunk, extract the sequence number and the data - */ - residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull)); - Assert(!isnull); - chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull)); - Assert(!isnull); - if (!VARATT_IS_EXTENDED(chunk)) - { - chunksize = VARSIZE(chunk) - VARHDRSZ; - chunkdata = VARDATA(chunk); - } - else if (VARATT_IS_SHORT(chunk)) - { - /* could happen due to heap_form_tuple doing its thing */ - chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT; - chunkdata = VARDATA_SHORT(chunk); - } - else - { - /* should never happen */ - elog(ERROR, "found toasted toast chunk for toast value %u in %s", - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - chunksize = 0; /* keep compiler quiet */ - chunkdata = NULL; - } - - /* - * Some checks on the data we've found - */ - if (residx != nextidx) - ereport(ERROR, - (errcode(ERRCODE_DATA_CORRUPTED), - errmsg_internal("unexpected chunk number %d (expected %d) for toast value %u in %s", - residx, nextidx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)))); - if (residx < numchunks - 1) - { - if (chunksize != TOAST_MAX_CHUNK_SIZE) - ereport(ERROR, - (errcode(ERRCODE_DATA_CORRUPTED), - errmsg_internal("unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s", - chunksize, (int) TOAST_MAX_CHUNK_SIZE, - residx, numchunks, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)))); - } - else if (residx == numchunks - 1) - { - if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != ressize) - ereport(ERROR, - (errcode(ERRCODE_DATA_CORRUPTED), - errmsg_internal("unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s", - chunksize, - (int) (ressize - residx * TOAST_MAX_CHUNK_SIZE), - residx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)))); - } - else - ereport(ERROR, - (errcode(ERRCODE_DATA_CORRUPTED), - errmsg_internal("unexpected chunk number %d (out of range %d..%d) for toast value %u in %s", - residx, - 0, numchunks - 1, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)))); - - /* - * Copy the data into proper place in our result - */ - memcpy(VARDATA(result) + residx * TOAST_MAX_CHUNK_SIZE, - chunkdata, - chunksize); - - nextidx++; - } - - /* - * Final checks that we successfully fetched the datum - */ - if (nextidx != numchunks) - ereport(ERROR, - (errcode(ERRCODE_DATA_CORRUPTED), - errmsg_internal("missing chunk number %d for toast value %u in %s", - nextidx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)))); - - /* - * End scan and close relations - */ - systable_endscan_ordered(toastscan); - toast_close_indexes(toastidxs, num_indexes, AccessShareLock); - table_close(toastrel, AccessShareLock); - - return result; -} - -/* ---------- - * toast_fetch_datum_slice - - * - * Reconstruct a segment of a Datum from the chunks saved - * in the toast relation - * - * Note that this function only supports non-compressed external datums. - * ---------- - */ -static struct varlena * -toast_fetch_datum_slice(struct varlena *attr, int32 sliceoffset, int32 length) -{ - Relation toastrel; - Relation *toastidxs; - ScanKeyData toastkey[3]; - int nscankeys; - SysScanDesc toastscan; - HeapTuple ttup; - TupleDesc toasttupDesc; - struct varlena *result; - struct varatt_external toast_pointer; - int32 attrsize; - int32 residx; - int32 nextidx; - int numchunks; - int startchunk; - int endchunk; - int32 startoffset; - int32 endoffset; - int totalchunks; - Pointer chunk; - bool isnull; - char *chunkdata; - int32 chunksize; - int32 chcpystrt; - int32 chcpyend; - int num_indexes; - int validIndex; - SnapshotData SnapshotToast; - - if (!VARATT_IS_EXTERNAL_ONDISK(attr)) - elog(ERROR, "toast_fetch_datum_slice shouldn't be called for non-ondisk datums"); - - /* Must copy to access aligned fields */ - VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); - - /* - * It's nonsense to fetch slices of a compressed datum -- this isn't lo_* - * we can't return a compressed datum which is meaningful to toast later - */ - Assert(!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)); - - attrsize = toast_pointer.va_extsize; - totalchunks = ((attrsize - 1) / TOAST_MAX_CHUNK_SIZE) + 1; - - if (sliceoffset >= attrsize) - { - sliceoffset = 0; - length = 0; - } - - if (((sliceoffset + length) > attrsize) || length < 0) - length = attrsize - sliceoffset; - - result = (struct varlena *) palloc(length + VARHDRSZ); - - SET_VARSIZE(result, length + VARHDRSZ); - - if (length == 0) - return result; /* Can save a lot of work at this point! */ - - startchunk = sliceoffset / TOAST_MAX_CHUNK_SIZE; - endchunk = (sliceoffset + length - 1) / TOAST_MAX_CHUNK_SIZE; - numchunks = (endchunk - startchunk) + 1; - - startoffset = sliceoffset % TOAST_MAX_CHUNK_SIZE; - endoffset = (sliceoffset + length - 1) % TOAST_MAX_CHUNK_SIZE; - - /* - * Open the toast relation and its indexes - */ - toastrel = table_open(toast_pointer.va_toastrelid, AccessShareLock); - toasttupDesc = toastrel->rd_att; - - /* Look for the valid index of toast relation */ - validIndex = toast_open_indexes(toastrel, - AccessShareLock, - &toastidxs, - &num_indexes); - - /* - * Setup a scan key to fetch from the index. This is either two keys or - * three depending on the number of chunks. - */ - ScanKeyInit(&toastkey[0], - (AttrNumber) 1, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(toast_pointer.va_valueid)); - - /* - * Use equality condition for one chunk, a range condition otherwise: - */ - if (numchunks == 1) - { - ScanKeyInit(&toastkey[1], - (AttrNumber) 2, - BTEqualStrategyNumber, F_INT4EQ, - Int32GetDatum(startchunk)); - nscankeys = 2; - } - else - { - ScanKeyInit(&toastkey[1], - (AttrNumber) 2, - BTGreaterEqualStrategyNumber, F_INT4GE, - Int32GetDatum(startchunk)); - ScanKeyInit(&toastkey[2], - (AttrNumber) 2, - BTLessEqualStrategyNumber, F_INT4LE, - Int32GetDatum(endchunk)); - nscankeys = 3; - } - - /* - * Read the chunks by index - * - * The index is on (valueid, chunkidx) so they will come in order - */ - init_toast_snapshot(&SnapshotToast); - nextidx = startchunk; - toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], - &SnapshotToast, nscankeys, toastkey); - while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) - { - /* - * Have a chunk, extract the sequence number and the data - */ - residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull)); - Assert(!isnull); - chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull)); - Assert(!isnull); - if (!VARATT_IS_EXTENDED(chunk)) - { - chunksize = VARSIZE(chunk) - VARHDRSZ; - chunkdata = VARDATA(chunk); - } - else if (VARATT_IS_SHORT(chunk)) - { - /* could happen due to heap_form_tuple doing its thing */ - chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT; - chunkdata = VARDATA_SHORT(chunk); - } - else - { - /* should never happen */ - elog(ERROR, "found toasted toast chunk for toast value %u in %s", - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - chunksize = 0; /* keep compiler quiet */ - chunkdata = NULL; - } - - /* - * Some checks on the data we've found - */ - if ((residx != nextidx) || (residx > endchunk) || (residx < startchunk)) - elog(ERROR, "unexpected chunk number %d (expected %d) for toast value %u in %s", - residx, nextidx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - if (residx < totalchunks - 1) - { - if (chunksize != TOAST_MAX_CHUNK_SIZE) - elog(ERROR, "unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s when fetching slice", - chunksize, (int) TOAST_MAX_CHUNK_SIZE, - residx, totalchunks, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - } - else if (residx == totalchunks - 1) - { - if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != attrsize) - elog(ERROR, "unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s when fetching slice", - chunksize, - (int) (attrsize - residx * TOAST_MAX_CHUNK_SIZE), - residx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - } - else - elog(ERROR, "unexpected chunk number %d (out of range %d..%d) for toast value %u in %s", - residx, - 0, totalchunks - 1, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - - /* - * Copy the data into proper place in our result - */ - chcpystrt = 0; - chcpyend = chunksize - 1; - if (residx == startchunk) - chcpystrt = startoffset; - if (residx == endchunk) - chcpyend = endoffset; - - memcpy(VARDATA(result) + - (residx * TOAST_MAX_CHUNK_SIZE - sliceoffset) + chcpystrt, - chunkdata + chcpystrt, - (chcpyend - chcpystrt) + 1); - - nextidx++; - } - - /* - * Final checks that we successfully fetched the datum - */ - if (nextidx != (endchunk + 1)) - elog(ERROR, "missing chunk number %d for toast value %u in %s", - nextidx, - toast_pointer.va_valueid, - RelationGetRelationName(toastrel)); - - /* - * End scan and close relations - */ - systable_endscan_ordered(toastscan); - toast_close_indexes(toastidxs, num_indexes, AccessShareLock); - table_close(toastrel, AccessShareLock); - - return result; -} - -/* ---------- - * toast_decompress_datum - - * - * Decompress a compressed version of a varlena datum - */ -static struct varlena * -toast_decompress_datum(struct varlena *attr) -{ - struct varlena *result; - - Assert(VARATT_IS_COMPRESSED(attr)); - - result = (struct varlena *) - palloc(TOAST_COMPRESS_RAWSIZE(attr) + VARHDRSZ); - SET_VARSIZE(result, TOAST_COMPRESS_RAWSIZE(attr) + VARHDRSZ); - - if (pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), - VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, - VARDATA(result), - TOAST_COMPRESS_RAWSIZE(attr), true) < 0) - elog(ERROR, "compressed data is corrupted"); - - return result; -} - - -/* ---------- - * toast_decompress_datum_slice - - * - * Decompress the front of a compressed version of a varlena datum. - * offset handling happens in heap_tuple_untoast_attr_slice. - * Here we just decompress a slice from the front. - */ -static struct varlena * -toast_decompress_datum_slice(struct varlena *attr, int32 slicelength) -{ - struct varlena *result; - int32 rawsize; - - Assert(VARATT_IS_COMPRESSED(attr)); - - result = (struct varlena *) palloc(slicelength + VARHDRSZ); - - rawsize = pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), - VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, - VARDATA(result), - slicelength, false); - if (rawsize < 0) - elog(ERROR, "compressed data is corrupted"); - - SET_VARSIZE(result, rawsize + VARHDRSZ); - return result; -} - - -/* ---------- - * toast_open_indexes - * - * Get an array of the indexes associated to the given toast relation - * and return as well the position of the valid index used by the toast - * relation in this array. It is the responsibility of the caller of this - * function to close the indexes as well as free them. - */ -static int -toast_open_indexes(Relation toastrel, - LOCKMODE lock, - Relation **toastidxs, - int *num_indexes) -{ - int i = 0; - int res = 0; - bool found = false; - List *indexlist; - ListCell *lc; - - /* Get index list of the toast relation */ - indexlist = RelationGetIndexList(toastrel); - Assert(indexlist != NIL); - - *num_indexes = list_length(indexlist); - - /* Open all the index relations */ - *toastidxs = (Relation *) palloc(*num_indexes * sizeof(Relation)); - foreach(lc, indexlist) - (*toastidxs)[i++] = index_open(lfirst_oid(lc), lock); - - /* Fetch the first valid index in list */ - for (i = 0; i < *num_indexes; i++) - { - Relation toastidx = (*toastidxs)[i]; - - if (toastidx->rd_index->indisvalid) - { - res = i; - found = true; - break; - } - } - - /* - * Free index list, not necessary anymore as relations are opened and a - * valid index has been found. - */ - list_free(indexlist); - - /* - * The toast relation should have one valid index, so something is going - * wrong if there is nothing. - */ - if (!found) - elog(ERROR, "no valid index found for toast relation with Oid %u", - RelationGetRelid(toastrel)); - - return res; -} - -/* ---------- - * toast_close_indexes - * - * Close an array of indexes for a toast relation and free it. This should - * be called for a set of indexes opened previously with toast_open_indexes. - */ -static void -toast_close_indexes(Relation *toastidxs, int num_indexes, LOCKMODE lock) -{ - int i; - - /* Close relations and clean up things */ - for (i = 0; i < num_indexes; i++) - index_close(toastidxs[i], lock); - pfree(toastidxs); -} - -/* ---------- - * init_toast_snapshot - * - * Initialize an appropriate TOAST snapshot. We must use an MVCC snapshot - * to initialize the TOAST snapshot; since we don't know which one to use, - * just use the oldest one. This is safe: at worst, we will get a "snapshot - * too old" error that might have been avoided otherwise. - */ -static void -init_toast_snapshot(Snapshot toast_snapshot) -{ - Snapshot snapshot = GetOldestSnapshot(); - - if (snapshot == NULL) - elog(ERROR, "no known snapshots"); - - InitToastSnapshot(*toast_snapshot, snapshot->lsn, snapshot->whenTaken); -} |