> open ended setHint api. It is our intent to make use this api so that > users can > sets these values without having to make use of OpenJPA specific apis > -- granted the hint name and value would be OpenJPA specific.
... for certain values of "our". I think that it's important that we discuss API decisions as a group, as they have significant impacts on the OpenJPA product moving forward. This is especially important when there are dissenting views on a particular API decision, as is the case here. Currently, most of the precedent in OpenJPA is to use OpenJPA-specific APIs, rather than untyped strings, whenever possible for fetch configuration and behavior. See the APIs for controlling the fetch batch size, or the lock level, or the maximum fetch depth. Personally, I much prefer that model of operation, since it provides strong typing where vendor-specific extensions are used, and thus raises the awareness of developers that they are using a proprietary feature. Using string key-value pairs is notoriously error-prone and difficult to refactor, and in my opinion detracts from the usability of the API. > accessed. In the case of static SQL, these hints would be defined > on a NamedQuery definition and not through runtime api. Again, I don't think that 'hint' is really the right word for describing lock and isolation levels. We could also create new annotations to describe the lock levels and isolation settings needed for the named queries; we do not need to constrain ourselves to what is available in the JPA annotations / XML. This will mean a bit more work on our part, but I think that we should figure out what the right decision is for our users, and work from there, rather than just doing whatever fits into what the JPA spec provides API-wise. Similarly, these facilities seem useful for regular EM.find() calls; one of the nice things about the FetchPlan is that an EM has a FetchPlan and a Query has one, so similar fetching configurations can be implemented in a common manner. Thoughts? -Patrick -- Patrick Linskey BEA Systems, Inc. _______________________________________________________________________ Notice: This email message, together with any attachments, may contain information of BEA Systems, Inc., its subsidiaries and affiliated entities, that may be confidential, proprietary, copyrighted and/or legally privileged, and is intended solely for the use of the individual or entity named in this message. If you are not the intended recipient, and have received this message in error, please immediately return this by email and then delete it. > -----Original Message----- > From: David Wisneski [mailto:[EMAIL PROTECTED] > Sent: Tuesday, April 03, 2007 1:24 PM > To: open-jpa-dev@incubator.apache.org > Subject: Re: svn commit: r525252 - in > /incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache > /openjpa/jdbc/sql: AbstractDB2Dictionary.java DB2Dictionary.java > > SQL provides capabilities for tuning of locking. In the case of DB2 > this involves setting the isolation level, update lock, result set > optimize set, etc. > JPA spec does not provide support for these concepts but does > provide a rather > open ended setHint api. It is our intent to make use this api so that > users can > sets these values without having to make use of OpenJPA specific apis > -- granted the hint name and value would be OpenJPA specific. > Furthermore, we are intending to support static SQL. Static SQL is > extremely important in the enterprise environment for our larger > customers because (1) it provides better optimization of SQL and (2) > auditability and security over who access the data and how it is > accessed. In the case of static SQL, these hints would be defined > on a NamedQuery definition and not through runtime api. > > On 4/3/07, Patrick Linskey <[EMAIL PROTECTED]> wrote: > > I'm a little nervous about this change still. I don't like > it that we're > > adding yet another way to configure locking, especially > since it seems > > like the lock level settings should be sufficient (or nearly so) to > > handle per-transaction / per-query lock levels. > > > > I also still do not believe that isolationLevel should be a hint; it > > seems more rule-like than hint-like. > > > > To date, the OpenJPA model has not been to piggyback on the > > Query.setHint() facilities for vendor-specific metadata, > but rather to > > use our OpenJPA extension classes (FetchPlan, etc.) to allow us to > > convey more structured data to the kernel. I think that the > isolation > > level should probably be part of FetchPlan (or possibly > JDBCFetchPlan), > > and the update information should be obtainable from the FetchPlan's > > read- and write-lock levels. > > > > I don't think that we should rush this change in just so > it's in 0.9.7; > > we can always delay 0.9.7 if it's a must-have, or have a 0.9.8 that > > follows soon thereafter. Generally-speaking, my experience > is that once > > code gets committed, it tends to not get cleaned up, so the argument > > "let's get it in for the release and then fix it later" > usually ends up > > turning into "let's get it in for the release". This seems > especially > > true for a change like this, that is exposing new APIs (the hints). > > > > Thoughts? > > > > -Patrick > > > > -- > > Patrick Linskey > > BEA Systems, Inc. > > > > > ______________________________________________________________ > _________ > > Notice: This email message, together with any attachments, > may contain > > information of BEA Systems, Inc., its subsidiaries and > affiliated > > entities, that may be confidential, proprietary, > copyrighted and/or > > legally privileged, and is intended solely for the use of > the individual > > or entity named in this message. If you are not the > intended recipient, > > and have received this message in error, please immediately > return this > > by email and then delete it. > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday, April 03, 2007 12:35 PM > > > To: open-jpa-commits@incubator.apache.org > > > Subject: svn commit: r525252 - in > > > /incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache > > > /openjpa/jdbc/sql: AbstractDB2Dictionary.java DB2Dictionary.java > > > > > > Author: wisneskid > > > Date: Tue Apr 3 12:34:59 2007 > > > New Revision: 525252 > > > > > > URL: http://svn.apache.org/viewvc?view=rev&rev=525252 > > > Log: > > > changes for JIRA OPENJPA-182 > > > > > > Modified: > > > > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/AbstractDB2Dictionary.java > > > > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/DB2Dictionary.java > > > > > > Modified: > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/AbstractDB2Dictionary.java > > > URL: > > > http://svn.apache.org/viewvc/incubator/openjpa/trunk/openjpa-j > > > dbc/src/main/java/org/apache/openjpa/jdbc/sql/AbstractDB2Dicti > onary.java > > ?view=diff&rev=> 525252&r1=525251&r2=525252 > > > ============================================================== > > > ================ > > > --- > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/AbstractDB2Dictionary.java (original) > > > +++ > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/AbstractDB2Dictionary.java Tue Apr 3 12:34:59 2007 > > > @@ -52,7 +52,7 @@ > > > supportsLockingWithOrderClause = false; > > > supportsLockingWithOuterJoin = false; > > > supportsLockingWithInnerJoin = false; > > > - supportsLockingWithSelectRange = false; > > > + supportsLockingWithSelectRange = true; > > > > > > requiresAutoCommitForMetaData = true; > > > requiresAliasForSubselect = true; > > > > > > Modified: > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/DB2Dictionary.java > > > URL: > > > http://svn.apache.org/viewvc/incubator/openjpa/trunk/openjpa-j > > > dbc/src/main/java/org/apache/openjpa/jdbc/sql/DB2Dictionary.ja > va?view=di > > ff&rev=525252&r1=> 525251&r2=525252 > > > ============================================================== > > > ================ > > > --- > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/DB2Dictionary.java (original) > > > +++ > > > incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/ > > openjpa/jdbc/sql/DB2Dictionary.java Tue Apr 3 12:34:59 2007 > > > @@ -15,13 +15,15 @@ > > > */ > > > package org.apache.openjpa.jdbc.sql; > > > > > > +import java.lang.reflect.Method; > > > import java.sql.Connection; > > > import java.sql.DatabaseMetaData; > > > import java.sql.SQLException; > > > import java.util.Arrays; > > > - > > > +import java.util.StringTokenizer; > > > import org.apache.openjpa.jdbc.kernel.JDBCFetchConfiguration; > > > import org.apache.openjpa.jdbc.schema.Sequence; > > > +import org.apache.openjpa.lib.log.Log; > > > > > > /** > > > * Dictionary for IBM DB2 database. > > > @@ -31,7 +33,18 @@ > > > > > > public String optimizeClause = "optimize for"; > > > public String rowClause = "row"; > > > - > > > + private int db2ServerType = 0; > > > + private static final int db2ISeriesV5R3AndEarlier = 1; > > > + private static final int db2UDBV81OrEarlier = 2; > > > + private static final int db2ZOSV8x = 3; > > > + private static final int db2UDBV82AndLater = 4; > > > + private static final int db2ISeriesV5R4AndLater = 5; > > > + private static final String forUpdateOfClause="FOR > UPDATE OF"; > > > + private static final String withRSClause="WITH RS"; > > > + private static final String withRRClause="WITH RR"; > > > + private static final String useKeepUpdateLockClause= > > > "USE AND KEEP UPDATE LOCKS"; > > > + private static final String > > > useKeepExclusiveLockClause="USE AND KEEP EXCLUSIVE LOCKS"; > > > + private static final String forReadOnlyClause = > "FOR READ ONLY"; > > > public DB2Dictionary() { > > > platform = "DB2"; > > > validationSQL = "SELECT DISTINCT(CURRENT > TIMESTAMP) FROM " > > > @@ -170,6 +183,18 @@ > > > if (isJDBC3(metaData)) { > > > int maj = > metaData.getDatabaseMajorVersion(); > > > int min = metaData.getDatabaseMinorVersion(); > > > + > > > + // Determine the type of DB2 database > > > + if (isDB2ISeriesV5R3AndEarlier(metaData)) > > > + db2ServerType =db2ISeriesV5R3AndEarlier; > > > + else if (isDB2UDBV81OrEarlier(metaData,maj,min)) > > > + db2ServerType =db2UDBV81OrEarlier; > > > + else if (isDB2ZOSV8x(metaData,maj)) > > > + db2ServerType =db2ZOSV8x; > > > + else if (isDB2UDBV82AndLater(metaData,maj,min)) > > > + db2ServerType=db2UDBV82AndLater; > > > + else if (isDB2ISeriesV5R4AndLater(metaData)) > > > + db2ServerType=db2ISeriesV5R4AndLater; > > > > > > if (maj >= 9 || (maj == 8 && min >= 2)) { > > > supportsLockingWithMultipleTables = true; > > > @@ -198,13 +223,221 @@ > > > } > > > } > > > > > > + /** Get the update clause for the query based on the > > > + * updateClause and isolationLevel hints > > > + */ > > > + public String getForUpdateClause(JDBCFetchConfiguration > > > fetch, boolean forUpdate) { > > > + String isolationLevel = null; > > > + Boolean updateClause = null; > > > + DatabaseMetaData metaData = null; > > > + StringBuffer forUpdateString = new StringBuffer(); > > > + try { > > > + // Determine the update > clause/isolationLevel the hint > > > + // overrides the persistence.xml value > > > + if (fetch != null && > > > fetch.getHint("openjpa.hint.updateClause") > > > + !=null ) > > > + updateClause = (Boolean)fetch. > > > + getHint("openjpa.hint.updateClause"); > > > + else > > > + updateClause = forUpdate; > > > + if (fetch != null > > > &&fetch.getHint("openjpa.hint.isolationLevel") > > > + !=null ) > > > + isolationLevel = (String)fetch. > > > + getHint("openjpa.hint.isolationLevel"); > > > + else > > > + isolationLevel = conf.getTransactionIsolation(); > > > + if (updateClause == false) > > > + //This sql is not for update so add FOR Read > > > Only clause > > > + forUpdateString.append(" > ").append(forReadOnlyClause) > > > + .append(" "); > > > + else if (updateClause == true){ > > > + > > > + switch(db2ServerType){ > > > + case db2ISeriesV5R3AndEarlier: > > > + case db2UDBV81OrEarlier: > > > + if > (isolationLevel.equals("read-uncommitted")) > > > + forUpdateString.append(" > > > ").append(withRSClause) > > > + .append(" > > > ").append(forUpdateOfClause).append(" "); > > > + else > > > + forUpdateString.append(" > > > ").append(forUpdateOfClause) > > > + .append(" "); > > > + break; > > > + case db2ZOSV8x: > > > + case db2UDBV82AndLater: > > > + if (isolationLevel.equals("serializable")) > > > + forUpdateString.append(" > > > ").append(withRRClause) > > > + .append(" > ").append(useKeepUpdateLockClause) > > > + .append(" "); > > > + else > > > + forUpdateString.append(" > > > ").append(withRSClause) > > > + .append(" > ").append(useKeepUpdateLockClause) > > > + .append(" "); > > > + break; > > > + case db2ISeriesV5R4AndLater: > > > + if (isolationLevel.equals("serializable")) > > > + forUpdateString.append(" > > > ").append(withRRClause) > > > + .append(" > > > ").append(useKeepExclusiveLockClause) > > > + .append(" "); > > > + else > > > + forUpdateString.append(" > > > ").append(withRSClause) > > > + .append(" > > > ").append(useKeepExclusiveLockClause) > > > + .append(" "); > > > + } > > > + } > > > + } > > > + catch (Exception e) { > > > + if (log.isTraceEnabled()) > > > + log.error(e.toString(),e); > > > + } > > > + return forUpdateString.toString(); > > > + } > > > + > > > + > > > + /** Override the DBDictionary toSelect to call > > > getOptimizeClause and append > > > + * to the select string > > > + */ > > > + public SQLBuffer toSelect(SQLBuffer selects, > > > JDBCFetchConfiguration fetch, > > > + SQLBuffer from, SQLBuffer where, SQLBuffer group, > > > + SQLBuffer having, SQLBuffer order, > > > + boolean distinct, boolean forUpdate, long start, long end, > > > + int expectedResultCount) { > > > + String forUpdateString = > getForUpdateClause(fetch,forUpdate); > > > + SQLBuffer selString = > toOperation(getSelectOperation(fetch), > > > + selects, from, where, > > > + group, having, order, distinct, > > > + forUpdate, start, end,forUpdateString); > > > + return selString; > > > + } > > > + > > > + public boolean isDB2UDBV82AndLater(DatabaseMetaData > > > metadata, int maj, > > > + int min) throws SQLException { > > > + boolean match = false; > > > + if > > > (metadata.getDatabaseProductVersion().indexOf("SQL") != -1 > > > + && ((maj ==8 && min >=2) ||(maj >=8))) > > > + match = true; > > > + return match; > > > + } > > > + > > > + public boolean isDB2ZOSV8x(DatabaseMetaData metadata,int maj) > > > + throws SQLException { > > > + boolean match = false; > > > + if > (metadata.getDatabaseProductVersion().indexOf("DSN") != -1 > > > + && maj ==8 ) > > > + match = true; > > > + return match; > > > + } > > > + > > > + public boolean > > > isDB2ISeriesV5R3AndEarlier(DatabaseMetaData metadata) > > > + throws SQLException { > > > + boolean match = false; > > > + if > (metadata.getDatabaseProductVersion().indexOf("AS") != -1 > > > + && > > > generateVersionNumber(metadata.getDatabaseProductVersion()) > > > + <= 530 ) > > > + match = true; > > > + return match; > > > + } > > > + > > > + public boolean isDB2ISeriesV5R4AndLater(DatabaseMetaData > > > metadata) > > > + throws SQLException { > > > + boolean match = false; > > > + if > (metadata.getDatabaseProductVersion().indexOf("AS") != -1 > > > + && > > > generateVersionNumber(metadata.getDatabaseProductVersion()) > > > + >= 540 ) > > > + match = true; > > > + return match; > > > + } > > > + > > > + public boolean isDB2UDBV81OrEarlier(DatabaseMetaData > > > metadata,int maj, > > > + int min) throws SQLException { > > > + boolean match = false; > > > + if > > > (metadata.getDatabaseProductVersion().indexOf("SQL") != -1 && > > > + ((maj ==8 && min <=1)|| maj <8 )) > > > + match = true; > > > + return match; > > > + } > > > + > > > + /** Get the version number for the ISeries > > > + */ > > > + protected int generateVersionNumber(String versionString) { > > > + String s = > > > versionString.substring(versionString.indexOf('V')); > > > + s = s.toUpperCase(); > > > + int i = -1; > > > + StringTokenizer stringtokenizer = new > > > StringTokenizer(s, "VRM", false); > > > + if (stringtokenizer.countTokens() == 3) > > > + { > > > + String s1 = stringtokenizer.nextToken(); > > > + s1 = s1 + stringtokenizer.nextToken(); > > > + s1 = s1 + stringtokenizer.nextToken(); > > > + i = Integer.parseInt(s1); > > > + } > > > + return i; > > > + } > > > + > > > + > > > + /** > > > + * Override the toOperationMethod of DBDictionary to pass the > > > + * forUpdateString. > > > + */ > > > + protected SQLBuffer toOperation(String op, SQLBuffer selects, > > > + SQLBuffer from, SQLBuffer where, SQLBuffer group, > > > SQLBuffer having, > > > + SQLBuffer order, boolean distinct, boolean > > > forUpdate, long start, > > > + long end,String forUpdateString) { > > > + SQLBuffer buf = new SQLBuffer(this); > > > + buf.append(op); > > > + boolean range = start != 0 || end != Long.MAX_VALUE; > > > + if (range && rangePosition == RANGE_PRE_DISTINCT) > > > + appendSelectRange(buf, start, end); > > > + if (distinct) > > > + buf.append(" DISTINCT"); > > > + if (range && rangePosition == RANGE_POST_DISTINCT) > > > + appendSelectRange(buf, start, end); > > > + buf.append(" ").append(selects).append(" FROM > > > ").append(from); > > > + > > > + if (where != null && !where.isEmpty()) > > > + buf.append(" WHERE ").append(where); > > > + if (group != null && !group.isEmpty()) > > > + buf.append(" GROUP BY ").append(group); > > > + if (having != null && !having.isEmpty()) { > > > + assertSupport(supportsHaving, "SupportsHaving"); > > > + buf.append(" HAVING ").append(having); > > > + } > > > + if (order != null && !order.isEmpty()) > > > + buf.append(" ORDER BY ").append(order); > > > + if (range && rangePosition == RANGE_POST_SELECT) > > > + appendSelectRange(buf, start, end); > > > + > > > + if (!simulateLocking ) { > > > + assertSupport(supportsSelectForUpdate, > > > "SupportsSelectForUpdate"); > > > + buf.append(" ").append(forUpdateString); > > > + } > > > + if (range && rangePosition == RANGE_POST_LOCK) > > > + appendSelectRange(buf, start, end); > > > + return buf; > > > + } > > > + > > > public SQLBuffer toSelect(Select sel, boolean forUpdate, > > > JDBCFetchConfiguration fetch) { > > > - SQLBuffer buf = super.toSelect(sel, forUpdate, fetch); > > > + sel.addJoinClassConditions(); > > > + boolean update = forUpdate && > sel.getFromSelect() == null; > > > + SQLBuffer select = getSelects(sel, false, update); > > > + SQLBuffer ordering = null; > > > + if (!sel.isAggregate() || sel.getGrouping() != null) > > > + ordering = sel.getOrdering(); > > > + SQLBuffer from; > > > + if (sel.getFromSelect() != null) > > > + from = getFromSelect(sel, forUpdate); > > > + else > > > + from = getFrom(sel, update); > > > + SQLBuffer where = getWhere(sel, update); > > > + String forUpdateString = > getForUpdateClause(fetch,forUpdate); > > > + SQLBuffer buf = > > > toOperation(getSelectOperation(fetch), select, > > > + from, where,sel.getGrouping(), sel.getHaving(), > > > ordering, > > > + sel.isDistinct(), forUpdate, sel.getStartIndex(), > > > + sel.getEndIndex(),forUpdateString); > > > if (sel.getExpectedResultCount() > 0) > > > buf.append(" ").append(optimizeClause).append(" "). > > > - > append(String.valueOf(sel.getExpectedResultCount())). > > > - append(" ").append(rowClause); > > > + append(String.valueOf(sel.getExpectedResultCount())). > > > + append(" ").append(rowClause); > > > return buf; > > > } > > > } > > > > > > > > > > > > > Notice: This email message, together with any attachments, > may contain information of BEA Systems, Inc., its > subsidiaries and affiliated entities, that may be > confidential, proprietary, copyrighted and/or legally > privileged, and is intended solely for the use of the > individual or entity named in this message. If you are not > the intended recipient, and have received this message in > error, please immediately return this by email and then delete it. > > > Notice: This email message, together with any attachments, may contain information of BEA Systems, Inc., its subsidiaries and affiliated entities, that may be confidential, proprietary, copyrighted and/or legally privileged, and is intended solely for the use of the individual or entity named in this message. If you are not the intended recipient, and have received this message in error, please immediately return this by email and then delete it.
