Improve pageinspect module
Now pageinspect can show data stored in the heap tuple. Nikolay Shaplov
This commit is contained in:
Teodor Sigaev
parent
13b30c16f3
commit
d6061f83a1
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@ -5,9 +5,9 @@ OBJS = rawpage.o heapfuncs.o btreefuncs.o fsmfuncs.o \
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brinfuncs.o ginfuncs.o $(WIN32RES)
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EXTENSION = pageinspect
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DATA = pageinspect--1.3.sql pageinspect--1.2--1.3.sql \
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pageinspect--1.1--1.2.sql pageinspect--1.0--1.1.sql \
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pageinspect--unpackaged--1.0.sql
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DATA = pageinspect--1.4.sql pageinspect--1.3--1.4.sql \
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pageinspect--1.2--1.3.sql pageinspect--1.1--1.2.sql \
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pageinspect--1.0--1.1.sql pageinspect--unpackaged--1.0.sql
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PGFILEDESC = "pageinspect - functions to inspect contents of database pages"
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ifdef USE_PGXS
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@ -27,8 +27,11 @@
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#include "access/htup_details.h"
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#include "funcapi.h"
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#include "utils/builtins.h"
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#include "catalog/pg_type.h"
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#include "miscadmin.h"
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#include "utils/array.h"
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#include "utils/builtins.h"
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#include "utils/rel.h"
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/*
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@ -54,6 +57,42 @@ bits_to_text(bits8 *bits, int len)
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}
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/*
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* text_to_bits
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*
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* Converts a c-string representation of bits into a bits8-array. This is
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* the reverse operation of previous routine.
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*/
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static bits8 *
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text_to_bits(char *str, int len)
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{
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bits8 *bits;
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int off = 0;
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char byte = 0;
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bits = palloc(len + 1);
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while (off < len)
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{
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if (off % 8 == 0)
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byte = 0;
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if ((str[off] == '0') || (str[off] == '1'))
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byte = byte | ((str[off] - '0') << off % 8);
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else
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("illegal character '%c' in t_bits string", str[off])));
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if (off % 8 == 7)
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bits[off / 8] = byte;
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off++;
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}
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return bits;
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}
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/*
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* heap_page_items
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*
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@ -122,8 +161,8 @@ heap_page_items(PG_FUNCTION_ARGS)
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HeapTuple resultTuple;
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Datum result;
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ItemId id;
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Datum values[13];
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bool nulls[13];
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Datum values[14];
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bool nulls[14];
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uint16 lp_offset;
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uint16 lp_flags;
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uint16 lp_len;
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@ -153,8 +192,9 @@ heap_page_items(PG_FUNCTION_ARGS)
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lp_offset == MAXALIGN(lp_offset) &&
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lp_offset + lp_len <= raw_page_size)
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{
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HeapTupleHeader tuphdr;
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int bits_len;
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HeapTupleHeader tuphdr;
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bytea *tuple_data_bytea;
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int tuple_data_len;
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/* Extract information from the tuple header */
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@ -162,12 +202,21 @@ heap_page_items(PG_FUNCTION_ARGS)
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values[4] = UInt32GetDatum(HeapTupleHeaderGetRawXmin(tuphdr));
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values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
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values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr)); /* shared with xvac */
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/* shared with xvac */
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values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr));
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values[7] = PointerGetDatum(&tuphdr->t_ctid);
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values[8] = UInt32GetDatum(tuphdr->t_infomask2);
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values[9] = UInt32GetDatum(tuphdr->t_infomask);
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values[10] = UInt8GetDatum(tuphdr->t_hoff);
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/* Copy raw tuple data into bytea attribute */
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tuple_data_len = lp_len - tuphdr->t_hoff;
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tuple_data_bytea = (bytea *) palloc(tuple_data_len + VARHDRSZ);
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SET_VARSIZE(tuple_data_bytea, tuple_data_len + VARHDRSZ);
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memcpy(VARDATA(tuple_data_bytea), (char *) tuphdr + tuphdr->t_hoff,
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tuple_data_len);
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values[13] = PointerGetDatum(tuple_data_bytea);
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/*
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* We already checked that the item is completely within the raw
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* page passed to us, with the length given in the line pointer.
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@ -180,11 +229,11 @@ heap_page_items(PG_FUNCTION_ARGS)
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{
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if (tuphdr->t_infomask & HEAP_HASNULL)
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{
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bits_len = tuphdr->t_hoff -
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offsetof(HeapTupleHeaderData, t_bits);
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int bits_len =
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((tuphdr->t_infomask2 & HEAP_NATTS_MASK) / 8 + 1) * 8;
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values[11] = CStringGetTextDatum(
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bits_to_text(tuphdr->t_bits, bits_len * 8));
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bits_to_text(tuphdr->t_bits, bits_len));
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}
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else
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nulls[11] = true;
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@ -208,7 +257,7 @@ heap_page_items(PG_FUNCTION_ARGS)
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*/
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int i;
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for (i = 4; i <= 12; i++)
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for (i = 4; i <= 13; i++)
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nulls[i] = true;
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}
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@ -223,3 +272,205 @@ heap_page_items(PG_FUNCTION_ARGS)
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else
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SRF_RETURN_DONE(fctx);
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}
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/*
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* tuple_data_split_internal
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*
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* Split raw tuple data taken directly from a page into an array of bytea
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* elements. This routine does a lookup on NULL values and creates array
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* elements accordindly. This is a reimplementation of nocachegetattr()
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* in heaptuple.c simplified for educational purposes.
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*/
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static Datum
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tuple_data_split_internal(Oid relid, char *tupdata,
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uint16 tupdata_len, uint16 t_infomask,
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uint16 t_infomask2, bits8 *t_bits,
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bool do_detoast)
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{
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ArrayBuildState *raw_attrs;
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int nattrs;
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int i;
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int off = 0;
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Relation rel;
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TupleDesc tupdesc;
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/* Get tuple descriptor from relation OID */
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rel = relation_open(relid, NoLock);
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tupdesc = CreateTupleDescCopyConstr(rel->rd_att);
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relation_close(rel, NoLock);
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raw_attrs = initArrayResult(BYTEAOID, CurrentMemoryContext, false);
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nattrs = tupdesc->natts;
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if (nattrs < (t_infomask2 & HEAP_NATTS_MASK))
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("number of attributes in tuple header is greater than number of attributes in tuple descriptor")));
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for (i = 0; i < nattrs; i++)
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{
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Form_pg_attribute attr;
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bool is_null;
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bytea *attr_data = NULL;
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attr = tupdesc->attrs[i];
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is_null = (t_infomask & HEAP_HASNULL) && att_isnull(i, t_bits);
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/*
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* Tuple header can specify less attributes than tuple descriptor
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* as ALTER TABLE ADD COLUMN without DEFAULT keyword does not
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* actually change tuples in pages, so attributes with numbers greater
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* than (t_infomask2 & HEAP_NATTS_MASK) should be treated as NULL.
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*/
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if (i >= (t_infomask2 & HEAP_NATTS_MASK))
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is_null = true;
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if (!is_null)
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{
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int len;
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if (attr->attlen == -1)
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{
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off = att_align_pointer(off, tupdesc->attrs[i]->attalign, -1,
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tupdata + off);
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/*
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* As VARSIZE_ANY throws an exception if it can't properly
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* detect the type of external storage in macros VARTAG_SIZE,
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* this check is repeated to have a nicer error handling.
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*/
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if (VARATT_IS_EXTERNAL(tupdata + off) &&
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!VARATT_IS_EXTERNAL_ONDISK(tupdata + off) &&
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!VARATT_IS_EXTERNAL_INDIRECT(tupdata + off))
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("first byte of varlena attribute is incorrect for attribute %d", i)));
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len = VARSIZE_ANY(tupdata + off);
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}
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else
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{
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off = att_align_nominal(off, tupdesc->attrs[i]->attalign);
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len = attr->attlen;
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}
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if (tupdata_len < off + len)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("unexpected end of tuple data")));
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if (attr->attlen == -1 && do_detoast)
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attr_data = DatumGetByteaPCopy(tupdata + off);
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else
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{
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attr_data = (bytea *) palloc(len + VARHDRSZ);
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SET_VARSIZE(attr_data, len + VARHDRSZ);
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memcpy(VARDATA(attr_data), tupdata + off, len);
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}
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off = att_addlength_pointer(off, tupdesc->attrs[i]->attlen,
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tupdata + off);
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}
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raw_attrs = accumArrayResult(raw_attrs, PointerGetDatum(attr_data),
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is_null, BYTEAOID, CurrentMemoryContext);
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if (attr_data)
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pfree(attr_data);
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}
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if (tupdata_len != off)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("end of tuple reached without looking at all its data")));
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return makeArrayResult(raw_attrs, CurrentMemoryContext);
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}
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/*
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* tuple_data_split
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*
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* Split raw tuple data taken directly from page into distinct elements
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* taking into account null values.
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*/
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PG_FUNCTION_INFO_V1(tuple_data_split);
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Datum
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tuple_data_split(PG_FUNCTION_ARGS)
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{
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Oid relid;
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bytea *raw_data;
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uint16 t_infomask;
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uint16 t_infomask2;
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char *t_bits_str;
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bool do_detoast = false;
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bits8 *t_bits = NULL;
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Datum res;
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relid = PG_GETARG_OID(0);
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raw_data = PG_ARGISNULL(1) ? NULL : PG_GETARG_BYTEA_P(1);
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t_infomask = PG_GETARG_INT16(2);
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t_infomask2 = PG_GETARG_INT16(3);
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t_bits_str = PG_ARGISNULL(4) ? NULL :
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text_to_cstring(PG_GETARG_TEXT_PP(4));
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if (PG_NARGS() >= 6)
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do_detoast = PG_GETARG_BOOL(5);
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser to use raw page functions")));
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if (!raw_data)
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PG_RETURN_NULL();
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/*
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* Convert t_bits string back to the bits8 array as represented in the
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* tuple header.
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*/
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if (t_infomask & HEAP_HASNULL)
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{
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int bits_str_len;
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int bits_len;
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bits_len = (t_infomask2 & HEAP_NATTS_MASK) / 8 + 1;
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if (!t_bits_str)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("argument of t_bits is null, but it is expected to be null and %i character long",
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bits_len * 8)));
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bits_str_len = strlen(t_bits_str);
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if ((bits_str_len % 8) != 0)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("length of t_bits is not a multiple of eight")));
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if (bits_len * 8 != bits_str_len)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("unexpected length of t_bits %u, expected %i",
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bits_str_len, bits_len * 8)));
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/* do the conversion */
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t_bits = text_to_bits(t_bits_str, bits_str_len);
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}
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else
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{
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if (t_bits_str)
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ereport(ERROR,
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(errcode(ERRCODE_DATA_CORRUPTED),
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errmsg("t_bits string is expected to be NULL, but instead it is %lu bytes length",
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strlen(t_bits_str))));
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}
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/* Split tuple data */
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res = tuple_data_split_internal(relid, (char *) raw_data + VARHDRSZ,
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VARSIZE(raw_data) - VARHDRSZ,
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t_infomask, t_infomask2, t_bits,
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do_detoast);
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if (t_bits)
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pfree(t_bits);
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PG_RETURN_ARRAYTYPE_P(res);
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}
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@ -1,4 +1,4 @@
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/* contrib/pageinspect/pageinspect--1.3.sql */
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/* contrib/pageinspect/pageinspect--1.4.sql */
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-- complain if script is sourced in psql, rather than via CREATE EXTENSION
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\echo Use "CREATE EXTENSION pageinspect" to load this file. \quit
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@ -48,11 +48,101 @@ CREATE FUNCTION heap_page_items(IN page bytea,
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OUT t_infomask integer,
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OUT t_hoff smallint,
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OUT t_bits text,
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OUT t_oid oid)
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OUT t_oid oid,
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OUT t_data bytea)
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RETURNS SETOF record
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AS 'MODULE_PATHNAME', 'heap_page_items'
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LANGUAGE C STRICT;
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--
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-- tuple_data_split()
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--
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CREATE FUNCTION tuple_data_split(rel_oid oid,
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t_data bytea,
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t_infomask integer,
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t_infomask2 integer,
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t_bits text)
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RETURNS bytea[]
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AS 'MODULE_PATHNAME','tuple_data_split'
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LANGUAGE C;
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CREATE FUNCTION tuple_data_split(rel_oid oid,
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t_data bytea,
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t_infomask integer,
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t_infomask2 integer,
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t_bits text,
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do_detoast bool)
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RETURNS bytea[]
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AS 'MODULE_PATHNAME','tuple_data_split'
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LANGUAGE C;
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--
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-- heap_page_item_attrs()
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--
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CREATE FUNCTION heap_page_item_attrs(
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IN page bytea,
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IN rel_oid regclass,
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IN do_detoast bool,
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OUT lp smallint,
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OUT lp_off smallint,
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OUT lp_flags smallint,
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OUT lp_len smallint,
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OUT t_xmin xid,
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OUT t_xmax xid,
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OUT t_field3 int4,
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OUT t_ctid tid,
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OUT t_infomask2 integer,
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OUT t_infomask integer,
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OUT t_hoff smallint,
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OUT t_bits text,
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OUT t_oid oid,
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OUT t_attrs bytea[]
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)
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RETURNS SETOF record AS $$
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SELECT lp,
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lp_off,
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lp_flags,
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lp_len,
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t_xmin,
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t_xmax,
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t_field3,
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t_ctid,
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t_infomask2,
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t_infomask,
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t_hoff,
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t_bits,
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t_oid,
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tuple_data_split(
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rel_oid,
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t_data,
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t_infomask,
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t_infomask2,
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t_bits,
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do_detoast)
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AS t_attrs
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FROM heap_page_items(page);
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$$ LANGUAGE SQL;
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CREATE FUNCTION heap_page_item_attrs(IN page bytea, IN rel_oid regclass,
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OUT lp smallint,
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OUT lp_off smallint,
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OUT lp_flags smallint,
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OUT lp_len smallint,
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OUT t_xmin xid,
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OUT t_xmax xid,
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OUT t_field3 int4,
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OUT t_ctid tid,
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OUT t_infomask2 integer,
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OUT t_infomask integer,
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OUT t_hoff smallint,
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OUT t_bits text,
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OUT t_oid oid,
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OUT t_attrs bytea[]
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)
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RETURNS SETOF record AS $$
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SELECT * from heap_page_item_attrs(page, rel_oid, false);
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$$ LANGUAGE SQL;
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--
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-- bt_metap()
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--
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@ -1,5 +1,5 @@
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# pageinspect extension
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comment = 'inspect the contents of database pages at a low level'
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default_version = '1.3'
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default_version = '1.4'
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module_pathname = '$libdir/pageinspect'
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relocatable = true
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@ -93,9 +93,10 @@ test=# SELECT * FROM page_header(get_raw_page('pg_class', 0));
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<listitem>
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<para>
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<function>heap_page_items</function> shows all line pointers on a heap
|
||||
page. For those line pointers that are in use, tuple headers are also
|
||||
shown. All tuples are shown, whether or not the tuples were visible to
|
||||
an MVCC snapshot at the time the raw page was copied.
|
||||
page. For those line pointers that are in use, tuple headers as well
|
||||
as tuple raw data are also shown. All tuples are shown, whether or not
|
||||
the tuples were visible to an MVCC snapshot at the time the raw page
|
||||
was copied.
|
||||
</para>
|
||||
<para>
|
||||
A heap page image obtained with <function>get_raw_page</function> should
|
||||
|
|
@ -110,6 +111,56 @@ test=# SELECT * FROM heap_page_items(get_raw_page('pg_class', 0));
|
|||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>
|
||||
<function>tuple_data_split(rel_oid, t_data bytea, t_infomask integer, t_infomask2 integer, t_bits text [, do_detoast bool]) returns bytea[]</function>
|
||||
<indexterm>
|
||||
<primary>tuple_data_split</primary>
|
||||
</indexterm>
|
||||
</term>
|
||||
<listitem>
|
||||
<para>
|
||||
<function>tuple_data_split</function> splits tuple data into attributes
|
||||
in the same way as backend internals.
|
||||
<screen>
|
||||
test=# SELECT tuple_data_split('pg_class'::regclass, t_data, t_infomask, t_infomask2, t_bits) FROM heap_page_items(get_raw_page('pg_class', 0));
|
||||
</screen>
|
||||
This function should be called with the same arguments as the return
|
||||
attributes of <function>heap_page_items</function>.
|
||||
</para>
|
||||
<para>
|
||||
If <parameter>do_detoast</parameter> is <literal>true</literal>,
|
||||
attribute that will be detoasted as needed. Default value is
|
||||
<literal>false</literal>.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>
|
||||
<function>heap_page_item_attrs(rel_oid, t_data bytea, [, do_detoast bool]) returns bytea[]</function>
|
||||
<indexterm>
|
||||
<primary>heap_page_item_attrs</primary>
|
||||
</indexterm>
|
||||
</term>
|
||||
<listitem>
|
||||
<para>
|
||||
<function>heap_page_item_attrs</function> is equivalent to
|
||||
<function>heap_page_items</function> except that it returns
|
||||
tuple raw data as an array of attributes that can optionally
|
||||
be detoasted by <parameter>do_detoast</parameter> which is
|
||||
<literal>false</literal> by default.
|
||||
</para>
|
||||
<para>
|
||||
A heap page image obtained with <function>get_raw_page</function> should
|
||||
be passed as argument. For example:
|
||||
<screen>
|
||||
test=# SELECT * FROM heap_page_item_attrs(get_raw_page('pg_class', 0), 'pg_class'::regclass);
|
||||
</screen>
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>
|
||||
<function>bt_metap(relname text) returns record</function>
|
||||
|
|
|
|||
Loading…
Reference in New Issue